recent purchase '82 RJ SECA idling high rpm when warm

Hi zhalbert

Same here!

Thank you oh mighty fitz!

Have a nice steady idle at 990-1030, (can go lower even!)

Just re-vacuum synched, and all 4 dials steady at @8 o'clock (idle mixture screws 2 and one half turns out.

Its obviously got to be colortuned, and I have just sent for one, so will update when received and performed colourtuning.....

Not taken for a run yet, so just waiting for a gap in this torrential rain here, and will take it out for a spin........hopefully everything will hold up(?)

Regs.

 

DO NOT set the idle too low; it's a plain bearing motor and it needs its oil pressure. It should be set at 1050~1100rpm; the fact that it's capable of idling lower just means you got it sync'ed up with adjustment left on the knob. Good going.

 

My colortune plug has just arrived.....

Been reading the 'science', in the notes.....
Referring to my symptom when idling (in zhalbert's thread...), it would seem that the intermittent 'popping' or backfiring whatever, at #s 3, or 4, could be due to an misfiring cylinder, now and again, due to incorrect mixture in one of (or both) the carbs......

"......When there is less air in the mixture, there is not enough oxygen to complete the burning process so some carbon monoxide is not changed to carbon dioxide and hydrocarbons (unburnt fuel) may be present in the exhaust................."misfiring may occur, and hydrocarbon levels. in the exhaust gas will rise"

:roll: Sounds like my symptom....(?)

Will attempt the colortune, and obviously, if I can fine tune ok, (and the symptom is eradicated) it is just the adjustment, but if I cannot fine tune on either cylinder, it points to pilot mixture screw component(s) inspection and/or reconditioning......?

Anything to add, anyone, in support or otherwise, of my diagnosis...?

8) Thanks to everyone who has contributed to my threads, and helped me along the way...........

Regs.

 

RE: misfire (in your other thread) http://xjbikes.com/Forums/viewtopic/p=3 ... tml#338059 may have nothing to do with mixtures...

 

You're right fitz - not mixture issue!

:lol: I think i've sorted it.....clamp on carb manifold to inlet head, was misplaced slightly on carb #3. (where the noise of 'sucking' or 'blowing' was coming from)

Repositioned it. (it wasnt sitting completely 'square' around the carb throttle mouth) Tightened it up.....started machine....reached temperature,......blipped throttle......no more symptoms!

And engine is idling more 'rhythmically', @1000 rpm without a little 'backfire' everytime I blip throttle.

Response is 'good' too...but not done colortune yet.....

Also want to take out for a good 5-10 mile run first, to see what it settles down to after....

Regs.

 

**************LATEST TODAY******************************
Talk about speak too soon.........

Just took it for 10mile run and halfway through idle rose to 1500, and at one point 2000! (at lights, had to turn off)

Thought it might have been change of vacuum pipe, as it had 'ridden up' the spigot spike, when I examined it when I got home....

Changed it back to the old pipe, and got it up to temperature again, (idle screw adjustment fully out), and up it went again to 1500, and stayed at that til I turned off.

If I blipped the throttle, the idle would come back down to 1000, then steadily, (sort of like a trot, into a canter) it goes up again to 1500+

Push down on the vacuum pipe, where it joins petcock, and also where it joins manifold, still wont bring the idle down...so its not that....?

Did spray test all around carb mouths, and where I had repaired the cracks in the manifolds - no drastic increase in revs.

I am presuming this is a vacuum leak again - but where?

The increase only occurs when bike reaches operating temperature, and it is only (?) +500+

Could it be that with taking the carbs off the rebench sync twice, that I've removed some seal off the cracks in the manifolds, and it only starts to leak at highest pressure, ie when at operating temp?

The throttle is not trapped anywhere, and the choke plungers are all down....

:roll: One thing I do remember when I was cleaning the carbs, and refurbishing them......one of the rubber diaphragm's had two very slight grazes, two cm apart........I held it up to a bright light, and could see no light coming through, so as per this site's guidlines, I 'assumed', it would need no repair..............? Could this be a cause of high idling once temperature is reached....

It was idling fine, and I had vacuum synched also. (see earlier in thread) It seems that something has happened, since I took it out for a test ride....

:? Anyone..............??

 

***************LATEST!!******************************

:wink: I really have sorted it this time......(?)

8O The return to high idling was due to my vacuum to petcock pipe leaking at the manifold spigot, (although couldnt hear or 'feel' it)
Also, I suspect, spigot plugs, on other three manifolds not seated correctly.........ie with spring clip sat in 'grooves'!!

Re-positioned, again, and tightened up fully, #3 (the original 'puffing' or 'blowing' intermittently) carb to manifold bracket.
Moved the vacuum pipe to petcock, from #3 manifold, to #1 manifold (easier access, and it doesnt matter which # manifold it is on(?)

Back to a nice easy 950-1000rpm idle, at temperature.

Didnt count my chickens tho' - re-vac synched (didnt need hardly any adjustment, apart from 3 and 4)

:lol: Just took out for a 20 mile run, and man is it S-M-O-O-T-H!!?

Had a few quick spurts of acceleration, up to 70mph, and then watched idle when I had to stop at lights/roundabout.......bike was well up to temperature by now, and NICE AND STEADY, @ 995rpm.....!!

Checked when I got home, and a nice quiet 995 still......
So pleased! - and I havent even colortuned yet.....

Thank you to everyone, who has contrbuted to my thread, and helped me to resolve my high-idling issue....!!!

Regs.

 

Excellent.

Now turn the idle up to 1050~1100.

 

Yes ok fitz!

Just read again in thread earlier....

What does that mean incidentally, 'a plain bearing motor, and it needs it's oil pressure'?

Why is it necessary?

Does it not get enough oil to cool or something, if the idle is less than 1050rpm, and the pressure is too low, and it overheats.....??

Regs.

 

In a plain-bearing motor, it's the oil pressure that keeps the bearings from digging into the crank. PLUS the fact that these motors depend on an "oil spray" system for cooling.

 

Right.

Thank you fitz.

Will make sure I dont let it idle below 1050......!

Many thanks for all your help...sure Ill be back for more soon!
Got to colortune yet........(?)!! Just sending for another one - I sent for 12mm one, instead of 14mm!

Regs.

 

Well, here I am back again!

Bike idles nicely up to operating temperature @1050-1100, as advised.....
When I take for run and go over 50-60mph, and the rpm's rise above 3500+, etc, I come to a stop at lights whatever, and the idle wont come down past 2250, and sticks at that.....

Turn off machine, .........idle comes straight down to 0 obviously.
Immediately turn back on and nice steady idle at 1050 (does not shoot up to 2500) again...????.............'til I set off again, get up past 50-60mph again, and the throttle probably about half open........come to a stop and sticks at 2250-2500rpm in idle again.....until I turn off.......and restart button again....steady idle...............

What is this please?

It is manageable, by just turning off, and then turning on again, a few seconds later, when you are to pull away again, but.......please!?

I did state earlier in my thread, that I noticed two small 'scuffs' or 'grazes', on one of the diaphragms in the top of one of the carbs, but I held it up to the light. as advised, and could not see any light thro'.........?

I have bought some liquid electrical tape since, to repair it, and I dont have to take the carbs off the bike again to do so, do I(?). If this is causing my symptom, (does damaged diaphragm cause my symptom - is it vacuum leak caused only when throttle half open, and piston is sticking or something)

Anybody have these symptoms, in the past.......any ideas?

Regs.

 

:? What had I done?
On advice given, made sure idle was at 1050-1100, and set off on my journey, but NOT UNTIL operating temperature, had been reached.
So - I had turned up idling knob, just after starting machine, from say 850-900, to 1050-1100, THEN set off......THEREFORE....6 miles down road, and nicely warmed up........stop at lights,...........idling at 2500+
I jumped to 'worst case scenario' mode.....
Today, waited til reached op temp, and a bit high on rpm's again, so just turned down idling knob....nice and steady again, even after short bursts of acceleration on 7 mile run.........
:roll: I've still got a little 'cough' now and again on #3 or 4, but that might come out in the wash when I colortune, next week......
Regs.

 

You're getting there. My 550s need a bit more than 7 miles to get fully warmed up. Try a 20-mile run, then adjust the final idle.

It does take a few additional "tweaks" as you use the bike to get the idle exactly right where you want it.

 

Just pulled plugs, to inspect their state after @100 miles, since cleaning carbs, and dry-bench synch/vacuum synch.
Idle mix screws set @ 2 and one half turns out each....

#1 plug - dry sooty black
#2 plug - EXTREMELY dry sooty black
#3 plug - almost completely clean - very LEAN (?)
#4 plug - a bit 'brown paper-baggy' - not far out (?) but still a little LEAN

RECLEANED THE PLUGS...........

*COLORTUNE JUST ARRIVED AS I'M WRITING THIS REPORT....*

I have snipped back HT leads, on 3 and 4, 10mm, replaced the caps (after cleaning them) and restarted....

If I take cap off #3 now, whilst idling, cuts-out (NOT FULLY WARMED UP THO')- obviously getting good spark now....

When I used to take cap off #4, when running, - there was no change in rhythm of rpm - now I snipped HT coil back a bit, - defininitely drops in rhythm (if only very slightly), til I replace it....

This diagnosis leads me to the understanding, that #s 1 and 2 pilot mixture screws need to be screwed 'IN', or DOWN, a fraction, if not more, because, these two, are running far too rich (I can smell fuel slightly, when first start up)
Conversely, #s 3 and 4, are running far too lean (before I snipped cables back(-could have been bad spark?), so I need to run again for a while, and recheck after a few miles, to see if the state of the plugs are not so lean, before I adjust pilot mixture screws on these two.....(?)

Am able to colortune now anyway......!!

Correct, anyone........?

Regs.

 

Im back again........!

Can only achieve 1400-1500 idle lowest, when all four carbs are same vac-synched.....idle knob all the way out....throttle cable not hangin...adjusted correctly at bars.....?

Colortune now across the board, well, apart from #4 being a bit 'sharp' but at the cost of high idle....!!

If I have #s1 & 2 carbs @xxx same reading, and #s 3 and 4 at YYY reading the same, I can get a desired idle, but when all in 4 sync......1500 idle. (at temperature)

If I turn down #4 carb's pilot mix screw 'down' or 'in' to very lean, the idle will drop, but then it will be running very hot, and cuts out the engine.

Just bought and installed all new pilot mix screw parts, but hasnt solved issue....

Cant find vacuum leak anywhere by spraying all around when engine running...

Have installed brand new throttle shaft seals, and fuel pipe o-rings....

Been conversing by pm with Len at Chacal, over this issue recently, and he was the one who instructed me that altho' I had got a decent idle (my last thread...) when 1 and 2 were the same vac sync, and 3 and 4 were the same vac sync, but both pairs different readings, - the engine was 'out of sync' if ALL FOUR cylinders were not exactly the same reading on each dial....

So, proceeded to get all four cylinders the same reading.....by adjusting sync screws...HIGH IDLE!
When I blip the throttle it responds immediately, but is very slow to come down to that 14/1500 idle...

I pulled the carbs today, and completely went over the #4 carb, because that seems to be the one that 'makes any changes' if I adjust the pilot mix screw, or the sync screw etc. (and it 'pops' when lean, of course....)

The main air jet is the wrong size @ #55, instead of #50, but otherwise everything is ok - checked piston, diaphragm, cleaned every orifice three times, nylon bristle in jets et al, and on, and on....

All the carb parts on #4 are in their correct positions....

Put a new set of innertube on manifolds, in case there was a vac leak there....
Started up.... and still the same....

Len said that even if all four main air jets were at #55, it would not change the idle as significantly as mine is high at the moment...I have got to search for other reasons.........

What the hell is it?....

Almost a year since I bought this bike, and so many pounds later, I have still got the original issue......??!!!

This is doing my head in! - I think Len has run out of options for me also..!!

Please, yet again....anyone??

 

Try unhooking the throttle cable at the carbs and starting again to see if idle still high.
No: cable routed incorrectly
Yes: move on to next area

You may have installed the butterflies backward/upside down when you did the shaft seals.

Did you replace pilot screw o-rings?
Is the enrichment cable allowing the enrichment plungers to fully seat when off?

Sorry if you have already answered these questions previously, I didn't go back and read the entire thread.

 

Thanks tkaz for your options....
Dont think its the throttle cable, but I'll try what you suggest.
I think the butterflys were reinstalled correctly....(when I did bench sync, I set them so that just about a third of one of the little holes was covered with the butterflys when closed) but you never know. However, cant tell unless I pull the carbs again....
And yes, I replaced with new, all pilot mixture screw parts, including the o rings (re positioned #4 today, and is adjusting nicely now)
I had come to the conclusion that, with #4 main air jet being a size(?) too big, @#55, instead of 50, possibly all the other three might be the same, and a PO, had changed them to tune with a change of exhaust (4 into one perhaps) or something.....?....Then, when another PO changed them back to stock exhaust, they didnt resize the jets in the carbs, back to stock, and so a high standard idle was being the result....?....however Len at Chacal says that even if all four were bigger, (havent checked them yet!) then it still wouldnt be idling as significantly high as it is? (1500 at temperature, instead of 1050-1100) 8O Do you agree?
Thanks.

 

I agree, going up 5 on one carb's air jet should not make a bit of difference.

It sounds like your problem is in the linkage itself, not any sort of air leakage. You'd be surprised at some of the things that can get stuck in a butterfly to hold them open.

One other thing, earlier in your post (finally got a chance to go back and read the entire thread) you said you had an increase in idle when spraying undeer the carbs at the bottom of the boots. Is there a chance that your carbs are not set perfectly tight onto the intake rubbers? I had a dandy of a time getting those carbs back in the boots the first few times i put them back on.

 

By chance, did you record the number and position of the air jets when you had the carb hats and diaphragms off? The Haynes has them listed incorrectly. If someone has messed with them previously and followed the Haynes not knowing this, would definitely cause lots of headaches.

 

Some relevant pointers.
#4 carb has been checked for sizes, positions, and apart from the main air jet size, are ok, but 1-3 carbs have not. Will take off and check all again.
As you re-iterate my theories - PO may have not returned to correct position, and/or different size whatever....
Will check the linkage is 'closing' properly when throttle blipped etc.
I did notice that #4 carbs butterfly, seemed to have been 'the most open', you could see almost all the hole, when I took the carbs off and looked at how the bench sync, 'was sitting', and when I cleaned that area, some bits of crusty old 'glue', at the point where the butterfly sits on the shaft and joins shaft seal washed away....??!!
When I refitted carbs yesterday, they seemed 'the most flush', and all 'popped' on. Tightened up clamps, and positioned correctly.
But will check again.....
Like you say, could be something simple, but easily overlooked.....
Regs tskaz.........

 

Just tried in idle at temperature, a few of the suggestions I could, without the carbs off....

Sprayed everywhere there might be vacuum leak - no increase in rpms
Idle at 14/1500.......

Disconnected the throttle cable from housing on top of carbs, so it hung loose.........idle fell to 1200....!....then rose again to 1250....!

Tried upping and downing, the sync screws, (carefully, and minutely!), and it just raised the idle, from what it was set at....not lowered it

Idle back up to 1300-1500, reconnected throttle cable....

Blip throttle and shoots to 2000, very slow to come back down to 1500....

8O BUT - if I push down on #2 (or 3, whatever, the middle one is!) sync screw, with my screwdriver on the head.... THE IDLE WILL DROP TO A NICE 1050-1100!!?? :wink: Is this signifying something to do with the bench sync settings need resetting really tight....or something sticking at the standard setting as it is now.....?
Regs.

 

If you can observe one Throttle Plate opened more than another, ... BENCH SYNC the Throttle Plates.

Using a Very Thin piece of material, set the Throttles to an EQUAL Setting by Measuring the Clearance of the Throttles, ... nearly closed.

Strips of 3X5 Card
Small Strips of 35mm Film Negative
Strips of Resume' Paper

Use the Material as Feeler Gauges.
Set the Throttles in Mechanical Sync as close to closed ad possible.

Use the Pilot Mixture Screws to get the Bike to Idle.
Allow the least amount of Throttles opened to Idle the Bike.

 

Thanks Rick
Just took carbs off to re-bench sync - took hats off first of 1-3 to check air jet sizes and positions............(#4 has already been established that the main air jet is #55 - wrong size, should be #50)................

#1 - Main - #55 Pilot - 195
#2 - Main - #55 Pilot - 195 (pilot hole is bigger at bottom and 'distorted' and off-centre)
#3 - Main - #55 Pilot - 195

This proves my theory, that some PO had upped the sizes of main air jets in ALL FOUR carbs, probably to fit pods to replace stock airbox, and/or four into one exhaust, to increase performance.........?
This would presumably 'tune-up' the carbs, to run in conjunction with the upgraded air/exhaust system.....?

It has since, by another PO, been returned to stock exhausts, which I received the receipt, with papers on purchase of this machine.....

Whosoever, reverted back to the stock exhaust system, obviously did not realise they should revert the air jets (main) back to stock #50s instead of the installed #55s.....?

8O So, it is not just the one carb, which is metering more air out than the exhaust system needs BUT ALL FOUR..!?

Would this be the cause of an idle of 14/1500 at temperature, instead of the required 1050-1100...? (probably works out at @+40%??)

Havent checked fuel jets in #s 1-3 yet, to see if theyve been changed to bigger/smaller whatever, (#4s fuel jets are correct for stock I think, - its hard to read the stamp, 'cos of wear marks, but looks like 110 main?)

:?: Anyone confirm this may be cause of my problem, or is it the same result if ALL FOUR main air jets are larger, and not just only the one in #4??


Thank you

 

............AND ANOTHER THING........
Just checked positons and sizes of main and pilot fuel jets.....
Main fuel jets are the right size #110, and positioned correctly....
PILOT FUEL JETS ARE #45 - WRONG - SHOULD BE #40!!!
On all four carbs.....
These have definitely been upgraded in the past to accomodate pods and intake/exhaust changes.....
So, another 40% + to the fuel metering?!
:roll: Surely this must be the reason for the high idling issues.....now stock exhaust, and stock air filter, and recently corrected valve clearances??
Anybody confirm please???
Regs.

 

#45 pilot jets are huge........should be #40's.

Might want to look at the main jets NEEDLES and make sure they are etched Y-10 on the shaft (just below the plastic head cap).

When you see one cockroach, you can bet that there's usually a few more than you haven't seen yet..........

 

Yeah no kidding. Do NOT look under the refrigerator.

All I can confirm is that with the carbs horribly mis-jetted, anything is possible.

However, I have two other concerns: You already know that something mechanical is hanging up; if you press on the linkage, the idle goes down. That needs to get fixed. If you broke the rack, you now have a whole lot of possibilities as to where that might be happening. Alignment, tab bindage, etc... fun.

Anytime you do anything with the SYNC screws without a vacuum gauge hooked up, you're going to make it less in sync than it was. And a hanging idle is the sure-fire sign of an out-of-sync condition.

 

Check for vacuum leaks too. Cracked intake manifolds and bad intake gaskets can contribute to your high idle issue.

 

The MAIN Reason for:
High Idle
Surging

Air Leaks ... somewhere.

If the Bike runs-up when WARM you night have what I refer too as an:
Occult Air Leak.

Air seeps-in at the Mating Surface of the Manifold and Head.
The Rubber Sealing "O-ring" is no longer viable.
Air sneaks-in past them.

Tightening the Cap Screws does not help because the Fasteners are Seized.
Running a Bead of Caulk ore RTV around the Manifold helps.
DON"T RISK Breaking-off a Bolt.

 

Thanks ALL!

So glad my investigations have proved fruitful, and this COULD BE the main contribution to the high idle.

I will obviously have to order new parts, and in the meantime (no, BEFORE(?), I will check to see if jet needles are stock size Y10.
Will check rack, rebench sync, check butterfly closures, everything to investigate possible hanging idle etc.
:roll: As I have repeated before, there is no evidence of vacuum leaks anywhere, and when spraying, at temperature EVERYWHERE, I can not find any (apparent) rise of rpm's (?).....but will take on board recommendations and follow thro' as best as I can...that 'surging' Rick refers to seems a familiar 'sound' when its at temperature, subtle, yet evident.....could be at carb to head joints, but spraying doesnt show it up.....?
:wink: Put carbs back on, do vac sync again, coloutune, sync, colourtune etc.... do these checks again for leaks, order parts as necessary, and use bike as it is for now til receive parts, cos this is my only bike now Ive sold my Virago 3 weeks ago........

Regs.

 

**********HIGH IDLE/RUN RESOLVED!!******************

Ordered, received and installed, new pilot fuel jets (#40) instead of the #45s, and main air jets (#50), instead of 55s, which were fitted.

Also resealed all around the carb to head manifolds, with black RTV, (OR IS IT RGV?), and a cylinder of bike innertube, on top. Put a bead of sealant around the manifold to head areas, whilst everything was off.

Reinstalled carbs, started up to temperature (nice 1100), vacuum synched, got it down to 1050-1100. 100% equal across dials......

Did a 'quick' coloutune, had to adjust throttle screw, a few times, to bring rpms down.....vac synced again......

Took for run, and what a difference! Acceleration, everything....

Got it back and did a plug chop,.....#2 a bit sooty, 1, 3, and 4, a very light brown.....slightly lean?

I think I need to colortune again, (I have got Dwayne's CD), I am aiming for the 'leanest', and therefore most fuel economic mix.....?

Says on CD, to try and achieve an 'electric blue' spark colour, across all four cylinders, to set it for most economic(?), as opposed to bunsen blue, for medium, and very dark blue(?), for a rich, high performance, and acceleration etc, mix.

I have been best part of 10 months, trying to find out what was causing the high idle, and having explored, and gone down almost every avenue, of causes and effects, it came down to a PO, some time in the past, had installed carburettors designed originally to be fitted to the Police bikes, which were sold to some forces in Europe(?)/and or East Asia.
God only knows where he acquired them..........!!?


Its cost me @ $200 in carb parts, alone, but the experience I have gained :wink: (I am an expert, and probably hold world time record in dismantling, and reinstalling carbs!!!), and knowledge accrued, has made it all worth it....!

Still got one more issue tho'............

Ever since I had the bike, it seems 'stiff', to change gears, a bit better when warm, but should surely be better than it is.....? Adjusted clutch cable where it has been advised, in threads, but not much better. I have ALWAYS pulled the clutch lever IN, every time I change gear...
Sometimes, 'clunks', when attempting to come up through neutral, from first into second, as tho its 'snagging' or not engaging........?...........the bike is 30 years old....could something need replacing (please dont tell me it is the clutch!!! plates, friction disc whatever.....)
What does any XJer with similar experience advise......?

Thank you to everyone who has contributed to my thread, especially Len, at Chacal, and everyone else, at XJ for his/their recognition of non-stock carbs, fitted etc, and his supply of the correct ones.....!

Many regards
Dale Grantham

 

Your transmission could just be worn, but that usually feels more like gears slipping, not clunking. I would guess that it's clutch--but don't fret, clutch replacement is quite easy. I have a how-to video in my signature for a Maxim, your should be identical.

All things told, it's fairly cheap to get a set of friction plates and a clutch cover gasket off of Ebay as well, if you're bargain hunting. I got a full set of friction plates for $40 if I remember right, and a gasket for $25 or something.

There are a couple tests you can do to feel out the state of the clutch without opening it, but I don't know them well enough to walk you through the procedures--either someone else will show up with advice, or you can look on youtube, which is bound to have someone walking you through motorcycle clutch diagnostics.

 

Thanks for info about the clutch - one for later.

Meanwhile...........once carbs synced all across four cylinders, same pressure etc.....colortuned all 4, (adjusting throttle screw as and when necessary) and when reached #4 carb, to get colour a nice bunsen blue...sends idle up to 1400+ again, (at temperature)

Throttle screw all way out - cant get less than 1400 idle at temp.
If I turn pilot screw 'in' so its almost white colortuned, nice (and considerably 'quieter') 1100 idle

I have had trouble with this #4 since I started, and even with new pilot mix screw components installed, same problem persists.....

Run it for a bit, (set at the 'very light blue' LEAN) and there IS a very light tan deposit, on bottom of plug.

Assume this is safe, not to overheat valve (?), but I think when I return, to vac sync again, it will be as it was before when this happened, that #s 1 & 2 cylinder guages, are not the same as #s 3 & 4!!

Is it that the #4 pilot jet screw threads are worn, and there is very little fine adjustment available, so it jumps from 1100, to 1400+, and an electric white/blue, to medium blue, and feels 'loose' and not 'spring loaded'? because after 3 and one half turns 'out', and after that, I cannot even get it to go to the dark blue and then 'yellow' (very rich) situation, even til its turned right out to uncscrewed!

:? Anyone make sense of this to contribute experienced advice??
Is the #4 cylinder, the most 'rich' one naturally....?? - Should I start colortuning at #4, instead of #1??

Anyone....?
Regs.

 

Thanks for info about the clutch - one for later.

Meanwhile...........once carbs synced all across four cylinders, same pressure etc.....colortuned all 4, (adjusting throttle screw as and when necessary) and when reached #4 carb, to get colour a nice bunsen blue...sends idle up to 1400+ again, (at temperature)

Throttle screw all way out - cant get less than 1400 idle at temp.
If I turn pilot screw 'in' so its almost white colortuned, nice (and considerably 'quieter') 1100 idle

I have had trouble with this #4 since I started, and even with new pilot mix screw components installed, same problem persists.....

Run it for a bit, (set at the 'very light blue' LEAN) and there IS a very light tan deposit, on bottom of plug.

Assume this is safe, not to overheat valve (?), but I think when I return, to vac sync again, it will be as it was before when this happened, that #s 1 & 2 cylinder guages, are not the same as #s 3 & 4!!

Is it that the #4 pilot jet screw threads are worn, and there is very little fine adjustment available, so it jumps from 1100, to 1400+, and an electric white/blue, to medium blue, and feels 'loose' and not 'spring loaded'? because after 3 and one half turns 'out', and after that, I cannot even get it to go to the dark blue and then 'yellow' (very rich) situation, even til its turned right out to uncscrewed!

:? Anyone make sense of this to contribute experienced advice??
Is the #4 cylinder, the most 'rich' one naturally....?? - Should I start colortuning at #4, instead of #1??

Anyone....?
Regs.

 

I'm beginning to think that #4 carb has a bit of persistent varnish in a passage somewhere, or something is worn (although more likely damaged by your PO) or damaged (a gouged passage from trying to clean with too agressive of an instrument maybe) or the throttle shaft itself is worn so that new seals do no good... or something.

It only takes one "rogue" carb to pull the whole bank up off idle.

"Naturally" speaking, #1 and #4 run cooler than #2 and #3 because of location. But your problem seems confined to #4 alone, and it seems to be the one that's causing the whole crew to misbehave. Is the vacuum spigot maybe loose in the top of the intake manifold?

 

Thanks fitz

The throttle seals are new, and checked installed correctly etc. I did carefully 'clean' with very fine (finer than orifice is), guitar wire, and carb cleaner, compressed air, at least 3 times....?
Checked spigot, cant find anything wrong with that.

I'm of the opinion, like you, that the orifice is 'worn' bigger, either by old age (if thats poss. with the aluminium?), or like you suggest, by someone using a thicker guage than the orifice itself, and so has made the 'metering' of the fuel/air mixture greater in volume, from any set point(?)

That, and/or thread is worn, at a certain point down the orifice, and that is why I can only achieve three specific points of mixture, namely, completely lean (screwed right 'in' - no colour whatsoever), a light whitey/blue (very lean - about 3 turns out to 4 turns out), a nice 1100, or less rpm, and some screw/spring resistance still, - and a medium/white blue (4+ turns out, to until completely unscrewed), no spring/screw resistance at all.

After 3-4 turns out, the screw seems 'loose' when adjusting, compared to when adjusting before this point.....?

As I reiterate, there is no advancement of colour change, after the third stage of medium blue/white, all the way out, (ie to darker blue, then indigo blue, then yellowy, whatever) AND STAYS AT 1400rpm - DOES NOT GO HIGHER??!

Could be that, at some point during tuning, over the years, and constant adjusting etc, the top threads, have been 'caught' perhaps, by the edges of the blade of a screwdriver....and resulted in them being worn away.....?
So - can I make the assumption, that this is most probably the cause (?), and to effect a solution, would be to obviously examine again, and/or try to recut the thread, make sure the passage if fully clear, (if being still a bit clogged would make this effect?), then try again, (to determine that it really IS then, a worn orifice, at the bottom?)

Probably, only option then, is a replacement carburettor?
Meanwhile, I assume, it is safe to run it in the lean state as the carb is at the moment?

Regs.

 

I'd find a "new" #4 carb.

 

WHY AM I UNABLE TO FINE TUNE/COLOR ADJUST #4 CYLINDER?!

Ive been conversing with Len at Chacal, by PMs
(asked if he could supply me with replacement #4 carb Fitz, - but he suggested trying other things first....)

I could only get, a very light bluey/white on #4 carb/cylinder trying to fine tune, by colortune.......if I got slightly darker blue- idle+ to 1400rpm.....

Just took bank off, and completely, cleaned with air jet, carb cleaner,finer guage guitar wire, the pilot mix screw components, shaft, pilot fuel jet, and shaft, pilot air jet, and shafts. And fuel enrichment circuit (choke) system on this carb - all clear. Did this three times. (the #4 carb)

However, looking at diagram in Haynes, there is a short internal shaft, that supplies the fuel to the pilot mix area from the fuel float bowl, after the pilot fuel jet, (runs horizontally internally), and I cannot get at it, to see if Ive cleared it. The pilot air jet joins onto this as well, to mix with the fuel the air supply, to the bottom of the pilot mix area.

Checked the size of the pilot mix hole at bottom, and it is the same as all the others, not bigger or worn or anything.

Checked the size of the pilot air jet, and that is correct, and not worn
Pilot fuel jet, is brand new, and correct size.........

Just put it all back together, and started up, nice idle at 1050-1100, up to temperature, and still at 1050-1100, tried to colortune again.....

#4 wont adjust at all, no matter how I turn it up or down!!!! - just a whitey blank firing situation. (and no change in rpms whatsoever) If I blip the throttle, get a white flash, and bit of yellow (that will be the main fuel jet wont it?)

I tried slightly applying the 'choke', at Lens instruction, to see if get a yellow firing situation, but first time I did it, got a quick yellow flash, and back to the whitey situation, and then when I turned the choke on again, it just kept cutting the engine out.

I have now got a steady idle, but at the cost, of no pilot circuit operation/adjustment on the #4 cylinder...?

What is happening please? Is the pilot circuit internally clogged, where it cant be seen, and I cannot get at it to clean it..........?

Anyone know? (the throttle shaft seal looked ok, by what I could see of it)

#4 is now running lean, even tho it feels like its not getting as hot as the others........???

Just taking it for a quick run, to see if I am getting any color on bottom of #4 plug.....

Regs.

 

Just returned from 2-3 mile run, and took #4 plug out of cylinder......completely clean! - no carbon deposit whatsoever.
The bike is running ok, and idle is steady at 1100, but no colour on spark plug??!!
Checked the plug is sparking by earthing onto cylinder head, and got a good spark, when turning motor over.
Looks like my attempts to 'clear' the offending obstacle, in one of the internal pilot circuit shafts somewhere, has only resulted in clogging it completely!!?
Anybody got any ideas.....ie a more efficient way of clearing an obstacle, in an internal shaft/tunnel whatever.....boiling water?.....injected thro' syringe....does this clear/dissolve hardened gum whatever.....?

All ideas welcome...cos Ive run out of options, and if I cannot resolve this, will have to insist on new/refurbished #4 carb (as Fitz suggested....!)
Regs.

 

So somewhere in the 6 pages this is probably already covered...
Did you check your carb flanges for cracks? It sounds like a lean condition produced by a softened flange. Or perhaps one of the caps on cylinders 1, 2, or 4. Or that hose on cyl 3...of course that would drop your fuel pressure if that leaked.

And as a cleaning solultion I just did the boiling water, boiling lemon juice method...not terribly effective. I went to Wal-Mart (of all places) and bought Berreman's (spelling) parts boil. It worked great! I had some stubborn grunge in the idle passage on the outside of the bowl of the carb. I literally just put a few drops of the boil in this passage and let gravity and time do the work. when I came back out, the boil lay in the bottom of the bowl and the passage was as clear as a whistle. I wouldn't reccommend boiling an entire carb overnight but isolating a passageway may work. Hope this helps you man.

 

Thanks snop

Will take carbs off today, to inpect again, and will look at what you suggest.
Where are the actual 'flanges' situated, that you mention....? Where would I locate 'a softened flange' ? Vac hose is now back on #2. Other caps aren't leaking.

I am now of the opinion, that my #4 carb pilot mixture circulation, has got a blockage somewhere (probably, somewhere in the pilot FUEL shaft feed, to the pilot mix screw area from the pilot fuel jet) - since I attempted to 'clean' this the other day - (there was just a partial block of the 'fuel' originally, cos I could only get mid-blue colortune extreme adjustment, and a 1400 idle, unless I turned the pilot mix screw right 'down' then 1100) - I cannot get any colour whatsoever now, so all I have succeeded in doing is blocking it completely....probably shoved the blockage further along the shaft?!...........idle has come down nicely tho!!, but #4 is running almost completely LEAN, when in idle mode...and no adjustment whatsoever when I turn pilot mix screw (its ok when Im in motion, cos the MAIN fuel jet kicks in when you open the throttle, and main jet fuel helps keep cool, and the carb is on the outside, receiving cold air flow, to stop it overheating, when Im riding..........) It runs fine....and also starts straight away, so my fuel enrichment circuit itself is not an issue(?), but I will still look at that also........!

I think there have been at least 7 or 8 POs, and this symptom could have been apparent, but not dealt with properly for many a year......and I have simply inherited it on purchase, and have to deal with it myself.....I'm not living with a 1400 idle, and potentially wasting one third of fuel, (because the idle is +500rpm continuously when engine is running) and only getting 2/3 of mileage per gallon......

It has been suggested (ALL I GET NOW IS BEING REFERRED TO 'THE CHURCH OF CLEAN'!), to try brake cleaner, to clear it.

I will search the web also for the carb 'dip', or 'boil cleaner' - Berreman's whatever, and if I need to, apply that.
Also, sonic cleaner, whatever that is......?

The thing is, I dont know what is actually causing the blockage, (grit, hardened gum residue, nylon or steel wire, aluminium or brass slither, bit of old cotton cleaning material, perished rubber o-ring perhaps(?) and therefore all I can do is carry out ALL the unblocking options available, and "do it again, and again and again, and again, and again", to the power of perpetuity.... until Ive cleared it.........

Regs.

 

Most likely (unless someone before you did something horrid) it's a bit of very stubborn varnish.

And yes, it's very possible that you succeeded in moving it further down the passage or causing it to "pack up" clogging the passage even more thoroughly.

The "dip" being referred to is Berryman's parts cleaner. It comes in a 1-gallon can (like a can of house paint) and you can soak a carb body in it (with the throttle shaft seals removed of course.)

Berryman's also makes a product called B12 Chemtool, a spray carb cleaner (similar to brake cleaner) but MUCH "meaner." This stuff WILL dissolve anything.

I can't tell you if Berryman's markets in the UK or not. However, there must be some equivalent products available to you.

A "sonic cleaner" is an ultrasonic parts cleaner that uses ultrasonic waves fed into the liquid to help break up deposits. The ones that are generally available are for cleaning jewelry, and not often large enough for carburetors. An automotive radiator shop may have a big one though.

Unfortunately, NONE of the above will be effective if what you're dealing with is a piece of something broken off in there by a PO.

And are you absolutely 110% sure you don't have an intake manifold-to-head leak on #4?

 

Well Fitz, I've just spent 4 whole hours, dismantling, and cleaning the #4 carb pilot mix circuit......and reinstalling etc.

Len has PM me with process to follow, to clean pilot circuit....

Took pilot fuel jet out, and pilot air jet out...took pilot mix screw, and components out.

Blasted thro circuit, with carb cleaner from air jet end.....came out pilot fuel jet end, pilot mix screw shaft, and tiny holes in ceiling of carburettor mouth.Followed that up with compressed air. Did this 3 times.

Blasted from fuel jet end....came out air jet, came out tiny holes in ceiling of carburettor mouth, came out pilot mix screw shaft. Followed that up with a few blasts of compressed air. Did this 3 times.

But wait! - I didnt stop there - injected brake fluid, whilst blocking up one end, and from both jet ends again, and let it 'soak' for half an hour. Also injected down pilot screw, hole, and 'tipped' to one side, so it would go down the tiny shaft at the bottom.....?!!

Blasted with carb cleaner, and compressed air again.

Cleaned all the carb bowl, and the main fuel jet screw head, which was a bit cruddy, and put it all back together.

Started bike, no problem.....had to turn out #4 pilot mix screw cos Id turned it right in......got some sort of adjustment again!

But - same as what is was in the first place, before I attempted to clear a couple of days ago......

Will only adjust 'out', to a very light blue colour, (wont advance past this colour) and will idle at 1400, unless I turn it 'in', so its still just firing on the #4 pilot circuit, but a very LEAN mix (unless I apply the throttle of course), and can get it to idle at 1100.- JUST - at temperature.

I might be advised otherwise, but I think I have done all I can do, within my capabilities, to resolve this....(apart from the 'dip' carb whatever...?), without having to search for a replacement #4 carb body.....? (if that will definitely resolve it?)

I do not know how 'time/wear worn' this carb body is, cos these carbs, have been installed, by a PO, some time in the past, and so cannot correspond to what it says on the clock/milometer. They are not the original stock carbs (see earlier in thread)

Does the pilot air, and fuel circuit shaft(s) wear with time, and a certain mileage is passed whatever? Or like you suggest, something has been stuck in there (might still be!), by a PO, and that is why it will only adjust between a narrower spectrum (there is definitely +air, and/or -fuel, in the pilot mix metering, at any given adjustment point)

I will look again (carb spray all around the #4 carb mouth/manifold head joint ) when at temperature, but if there is no other way of determining a vac leak (dont think its at spigot either), I have tried this before...but as you suggest....to be 110% sure......?!!

Vac leak isnt the cause of this symptom, by the evidence displayed anyway, is it...???

Thanks Fitz again, for your attention, and reply

Regs.

 

It could still be a vacuum leak, for sure.

BUT I'm more inclined to think that the pilot needle seat might be corroded or damaged; where the tapered tip of the pilot needle actually has to close down a gap to regulate the mixture. If a PO horribly overtightened the screw at some point, or something got jammed in there that damaged the seat, or if it's pitted from being the carb most exposed when the bike is on the sidestand---

Take the pilot screw and components out. Carefully examine the tapered tip; and then get a bright light and a magnifying glass and inspect the bottom of the bore and seat.

You mentioned that you think the threads might be trashed in such a way as to allow an air leak past the pilot screw threads in certain screw positions. The next time you're fighting with it, use a (GLOVED) fingertip and block the pilot screw hole, see if it changes the mixture noticeably.

 

Good point fitz, - I'll look at that, and try the tip you suggest.

I did look at the needle point previously, and could not see any 'wear', but do not know what wear would look like on these......?

I did also, inspect the aperture, at the bottom of the channel, and the pilot needle seat, and the diameter of the hole is the same as the others, but I didnt compare, the size of the bore of the 'seat' as such, with the others, for wear, whatever....(I assume what you are suggesting is that it, or the needle point, may have been worn or damaged, so as to make it ?%ineffective as to adjustment of the mix)?

Just been out for a quick run, and when I got back, idling at 1100, (very warm) and wont come down anymore, with throttle screw, backed out all the way...is this how it should be when at op temp (?) - cannot get lower than 1050-1150, screwed all the way out - is that correct, only get higher when turning throttle screw inwards.....?

I sprayed all around the carb, and the valve inlet area/manifold etc, with carb cleaner, and it didnt change the idle whatsoever.....

The bottom of #4 plug, has got the beginnings of a very light tan/beige (only 2 mile run), so I am probably achieving, only a very, VERY, lean mix, (pilot circuit plus main circuit whilst running), at 1100 idle. If I turn it up, to the richest it will go, - a very light whitey/blue, the idle raises to 14-1500, and stays at that level, even til the pilot screw is backed all the way out....

I havent vac-synced again yet tho' and it will need doing again, obviously because I have managed to get a (VERY) slight assemlance of fuel richness in pilot circuit on the #4 cylinder again....

NOW CONFESSION TIME while I think about it..........

I did tell Len, a while ago, when adjusting my valve clearances, and changing a shim, that when turning the crank, with the shim tool in place, (I think, on #4!?) I turned it the wrong way, and created a very slight dent -very small, at the back of the top of the bucket, at the level where the shim sits.......did not crack the head!!?? - HAVE ANYTHING TO DO WITH MY MIX PROBLEM?? - AFFECTING THE PRESSURE....?

Len insisted, it would not affect the idling, (cause a vacuum leak?) as such, but might need dealing with as a future precaution, in case a shim might pop out, and cause all sorts of problems.......!

Has this disclosure got anything to do with the symptoms present....

Regs.

 

Your dinged bucket wouldn't cause this.

The idle spec is 1050~1100 rpm. You don't want it lower than 1050 anyway.

Once you get some sort of color on the plug, re-do the vac sync then re-visit the mixture adjustment.

What I was talking about was indeed the potential for there to be damage to the seat where the tip of the needle goes. Just be sure it's not pitted or obviously torn up.

 

The carb boot/flange I referred to is the rubber between the carb and the engine. I've seen these cause big problems on snowmobiles when they crack, even slightly. It creates a lean condition after fuel mix for two reasons:

1) Outside air is introduced to the system after the mix is made.

2) Negative pressure (from piston downstroke) required to pull fuel in is now not aquired solely from the venturi of the carb but through the crack in the boot. This will destroy your 'adjustability.'

Also check the boot between the carb and airbox. The system is designed around the pressure created by that box. If that is not to initial design (i.e. leaking) you will always be slightly lean.

As far as the parts cleaner I didn't see that you were in the UK, my apologies. Check amazon.com. Its about $US30. There are alot of carb/parts boils available. I only reccommend Barrymans because it worked well for me.

But I'm really leaning to something rubber (i.e. carb boot, vaccuum line, cylinder to base gasket, head gasket, maybe a warped head, although unlikely). The fact that it worsens when warm leads me to this.

I think I read above that you have, but have you tried (while the machine is symptomatic) spraying WD-40, Gumout (carb cleaner) or something similar around the cylinder and carbs when the engine is running? If there is a leak it will pull the cleaner in and the engine will idle down slightly.

Is your fuel supply line slightly kinked? When it gets warm it could be kinking completely. Again just throwing it out there. It seems to me if it were a clogged passage it would run worse cold than warm as most engines need more fuel to warm up. You have the opposite problem. I really think you have a fuel restriction CAUSED by heat or an airleak CAUSED by heat.

Hope my opinion isn't irriating you...just trying to help.

Your ingintion coil could also be failing. I believe if you're talking about cyl #4 this would be the coil on the left side of the machine. Coils are known to fail under heat.

 

No, not irritating me at all snopro - I am grateful for any theories or opinions that will possibly get me closer to solving this issue.....

As far as the possible vac leak is concerned, I believe I have eradicated all possible sources because: a) I have completely sealed any cracks that were in the carb to head rubber manifolds (flanges to you!), with rtv black heat resistant sealant, with an extra rubber innertube cylinder seal on top.
Checked all around these areas with carb spray, when at temp., and no change in rpms.

I also put a bead of the sealant all around where each manifold 'mouth' meets the head......

b) checked all manifold spigots (and the vacuum lead) for leaks when at temp. with spray, and no change in rpms.

At present the only time the rpms will rise above the required idle, from 1100, to 1400 or slightly more, is when I am attempting to adjust the #4, pilot mixture screw, so I can get a 'richer', mix, and because (as fitz has suggested) perhaps, there is wear or damage somewhere in the region of the pilot mix socket, at the bottom seating (pitted, or larger) or the top threads,(air sneaking down the side of worn threads) or on the needle itself, this has 'allowed' a higher percentage of air in the mix, than the fuel is, from any set point whatever.....ie cant get the desired mix in the first place, so as I try to get richer, (and/or any blockage in fuel pilot), just gets leaner, and idle rises......?
Make any sense of this? I know what I am trying to describe, but its very hard to illustrate with words alone!!

I HAVE NOT CHECKED THE BOX TO CARB BOOTS WITH SPRAY, WILL TRY THAT - ESPECIALLY AT #4.
The fuel supply line is not kinked in any bizarre fashion, and does not get hot.
The vacuum hose, is now situated on #2 manifold, cos it keeps going brittel with heat, and have had to shorten it, to reach tank at other end - it is not leaking tho....

Carbs 1-3 are operating fine. The problem is something on #4. DEFINITELY.

Checked ignition of 4 by earthing on head, and bright continuous spark....


Regs.

 

Airbox to carb boots wouldn't cause this unless one were split.

I honestly think the carb body is damaged somehow, not by your efforts but by the hack who had it before you.

The next time your order from Len, get a new hunk of real vacuum line.

Back to a couple of simple things: you're 100% sure of the float level on #4; and you've replaced the float valve body-to-carb sealing washer. (Just saving myself doing a lot of scrolling and reading, sorry.)

 

Fitz, the carb float bowl gasket, is intact, but one of the screws on the float bowl-to-body, has been replaced by a small nut and bolt (very tight fit), and another one I can only get finger tight, before it slips ( the thread in the body is stripped - tried retapping, but to no avail) Havent got space to put nut and bolt replacement on it at the top. Put threadlock on it. The other two are tight.
No petrol is leaking from the bowl, at any operation.

The fuel levels on 1-3 were all @ 4mm exactly, and #4, was @ 3.2mm...?

I found out I could not get any sort of adjustment on #4 the other day, because when I took the idle mix screw and components out yesterday, the o-ring was damaged, so I replaced it.....!

Vac-synced this morning and achieved nice steady #8 across all four dials
I have been on 15 mile run, (starting warm idle at 1100, stationary)screw all way out, and when I returned, idle was at 1500, and there was a very slight tan on bottom of #4 plug......

Tried to colortune #4 again, whilst still at temperature......turn 'in' to 3 and one half turns out, drops idle to 1050-1100...... turn in more, and cuts motor out.

Turn 'out' from 3 and one half turns to up to 4, and beyond, and the idle rises to 1450-1500, and will stay at that rpm, til the pilot mix screw is turned all the way out......?

The idling rpms on the regular plug, and the colortune plug, are not the same, when whichever, is installed......? (when colortune plug is installed, the rpms are about 250 lower, than when regular plug is installed, and it takes another half-one turn out, on the pilot mix screw, to obtain same rpms as what it does on the regular plug - probably cos reg. plug is better 'earthed' and sparking at a higher rate, with suppressor cap, and closer to engine etc.?)

The colortune spark colour:
Seem to get (sometimes!) a light medium blue (when at 14-1500rpm) on colortune plug. - 3 and three quarters out and beyond to infinity!, and a very whitey light blue at (1000 - 1100rpm) - just over 3 and one half turns out, to 3 and one quarter to half turns out! - any further turned in, and the engine cuts out.

ACTUALLY - Just tried again, and its dark now outside, and the color, when running at 1050-1100, looks more deeper, like a bunsen blue, at just over 3 and a half turns out.......!??
Had it like this before, I think tho', and still hardly any carbon on bottom of plug after checking, in the past......

Anyway, I tried that 'put a gloved finger over the top of pilot mix screw aperture etc.' and it did not change the idle whatsoever, so I suppose, it can be summised, that air is not creeping down the side of the threads and + air that way......(the threads look ok, anyway fitz)

UPDATE 1PM MON........
Just examined seat and well on #4 sync screw shaft, and compared with #1 - (which is operating 'perfect') both look the same.....the needle is same also......Re-synced.......colortuned.....Resynced....can get idle of 1050, if I turn down #4 mix screw, so its hardly showing a colour,(and #3!) - OR - adjust the sync pressures, so that 1 & 2 dials are showing 10, and 3 & 4 dials are showing '8'.....??

I have uploaded a diagram with parts I think are, or may be partially blocked, on #4(?), thus reducing the potential % of fuel required to meter a 'correct' mix, to adjust. The parts of the shaft I think may be blocked (two right angles involved!!) are shaded in orange, and the black filled in is where I can actually physically clean, whereas the 'x's, are the points where I have attempted to clean from, whilst trying to block one of the others off at the same tim (in between 'soaking' with brake cleaner)......

The sync is set @#10, on dials 1 & 2, and #8 dials 3 & 4., and 'leaned down@ #s 1 & 4,colorwise so that I can get 1100, at temperature (i NOW HAVE SOME 'FIRING' COLOUR ON ALL FOUR PLUGS............I know this makes each pair not in sync, but.....until I can resolve.....IS IT OK TO RUN IT LIKE THIS - NO LONG TERM DAMAGE....?

REGS.

Regs.