Adjusting newly-cleaned carbs (no Yics-tool)..

Described my cleaning and reinstallation here: http://xjbikes.com/Forums/viewtopic/t=2 ... rt=45.html

- and have now tested..

Turns out I´m running (too) lean (mixture screws turned out 3 turns). Plugs whitish/grey and idle creeping when warm (2-3500 rpms). (Didn´t pre-sync the carbs before installing - stupid; I know).

Í didn´t check for false air (gonna get some start spray tomorrow) but all carb rubbers looked fine, when I reinstalled (also all plugs are equally coloured)..

Also haven´t yet checked if my throttle cable is hanging (don´t think so but will do).

I got a Clortune (3 day delivery from UK to Denmark) and have a borrowed Morgan Carb-tune but no YICS-tool. should I try to sync and mixture-adjust without the tool to see if I can get rid of the lean-ness?

Can´t find the thread, but somebody asked if you couln´t just use a almost-fitting metal rod through the Yics passage - to do some blockage of the connections. Would it be worth a try, or?

Any comments or things I forgot but could be worth checking? (I´m hoping, of course, that I don´t have to disassemble the carbs again - though reinstalling wasn´t so hard as expected).

 

If I recall correctly, they were wanting to use a full length of fuel line or similar, with a rod through the middle, then compressing the line with a washer and nut. Basically instead of using 3 seperate blockers to isolate the passages, blocking them all off with one big piece. I dont think a metal rod would work too well, because even the slightest leak of atmosphere between the passages would make your results screwy.

I was able to get all the parts from Home Depot to build 2 YICS tools for like $10, and built one in about half an hour (never did put the other together)...

As for your running issues, I'd pull the carbs off and bench sync them. It's nothing more than popping them off the holders, and using a feeler gauge ( or WD-40 tube) to make sure the butterfly valves are all about the same amount open). The difference my bench sync had was night and day, even though my carbs were spotless.

 

Ok, I see. Hm.. then might as well try and make the tool, then..

I haven´t been able to track down silicone hose that I trust is more heat resistant than f.i. fuel hose..

Part of the reason why I didn´t bench sync them was that I was confused with recommendations; Wd-40 tube and a piece of paper is quite differrent in thickness, I think. But maybe the importance is that they are evenly open?

Thanks gremlin - may be easiest to pop them off and bench sync..

 

Gremlin nailed it on the YICS tool and needing something to expand and close off the passages. I would not remove the carbs and bench sync. I would try the Carbtune first. You could tune with it and be DONE! It will sync without the YICS tool but will be a little harder. Still closer than bench syncing.
PM injuneer to find out about where to get some high temp silicone tubing.

 

Agreed - don't pull the carbs to bench sync now. Only reason to bench sync if you are going to vacuum sync is to make sure it runs so you can vacuum sync it.

For clarification on bench synching: Synching is to make sure all the butterflies are open the same amount. Idle stop screw controls the amount they are open.

 

I used fuel line on mine. I figured it wasn't in there for more than 10 minutes, so I really didn't think much of sourcing the really high temp stuff... It ended up working just fine.

 

Thanks guys for the advice and clarification; I´ll hook up a fan and the carbtune and see how it looks.

 

I used fuel line on my unit and haven't had a lick of trouble yet. Best of luck to you Finn.

 

Thanks Robert

An update: Synced the carbs today: 1+2 even, 3 low and 4 way too high. Got them down to an equal level though the idle kept being very finicky; it would race when the engine got warmer and even when the sync was ok, when I blipped the throttle, the revs were only slowly coming down.

Put in the Colortune and no matter how much I turned out the mixture screw, the flame stayed blue..

I ended up checking the fuel levels (on the 2 outer carbs) (which I had previously outruled, while they were dead-on in the bench with the carbs levelled) - and they were 2-3mm´s low! :?

So - the carbs are now on the table again...Gonna check them levels; maybe the diffence in that the carbs are tilted slightly forward when on the bike, means something? gonna start by checking them levelled (like before I reinstalled them) and then try to imitate how they sit on the bike (measured the forward tilting to 7mm difference from rear to front floatchamber gasket-edge).

I´ll be back 8)

 

The combustion FLAME is SUPPOSED to be BLUE.

You run the Pilot Screws IN until it starts to show traces of Orange or Yellow ... then, back out until it's a pretty BLUE and it's Done!
. . . . . . . . . . . . . . . .

The #-3 Carb is the BASE Carb. Everything should be Bench Synced to match-up with the 3-Carb. There's NO adjustment on 3. Open it with the Manual Idle Adjustment Rod.

Then, match 1 -to- 2 ... 4 -to- 3 ... finally, 2 -to- 3. Since 1's connected to 2 when you adjust 2 -to- 3 ... the 1 Carb goes along for the ride.

 

I know it´s supposed to be blue - but being quite sure the bike is running lean judging from the look of the plugs and the hunting idle, I was quite eager to get away from that - to see the orange colour..

I think you´re wrong about turning the mixture screws in will richen the mixture - I´ve read the opposite..

My scenario was, i couln´t get any sign of yellow/orange no matter how far out I turned the the mixture screw.

I may have found three possible causes:

1: The mentioned difference in float bowl fuel level - from levelled in a bench and slightly tilted on the bike - a difference I verified by checking the 2 positions in the bench afterwards. the difference in fuel level is 4 +/-1mm..

2: My temporary fuel tank (from a lawnmover) was probably too small (approx. 3/4 liter). I used it at first in the bench test afterwards but got no (!) fuel through the floatbowl drain plug (checked on 2 floatbowls) - though it was elevated fine and no restriction in the supply hose...(I did notice the inline filter while syncing and using this tank was only half full..)

3: False air: Prior to syncing I made a start spray-test and I had a sligt increase in revs from a couple of places: Around the cylinder intake rubbers and/or the vacuum nipple plugs - and around to of the diaphragm covers (gonna follow your advice on synthetic grease for seating and sealing the diaphragms when reassembling - I didn´t read it before I assembled the first time, and it was a bit scary not being able to see, if the diaphragm stayed in the groove, while mounting the cover...).

So - what confuses me the most is issue no. 1. gonna try and set the float height according to the service manual (a couple of mm´s higher than they are now - and check the fuel level again).

thanks for the info on bench syncing - I´ll use it as reference to check todays vacuum sunc.

 

Those heights are fine. Technically, fuel-level1.jpg is a smidge too-high ... but, missing high isn't a problem.

That first pic ... with the level at the top of the screw is Purr-fect-toe.

I Closed-off ... all the way IN ... my screws and ran-it-out until the cylinder started firing ... and kept tweaking it out until the flame was steady yellow-orange ... it seemed to stay like that for almost a full turn ... then started being blue with flashes of yellow and then it got blue to stay.

 

Finn; Let me know if you can't find tubing for your YICS tool. I can send you some (good for 500 degrees +) Or, I could build you a YICS tool like the one I made. Either way, I'll get you set up if you need it. PM me.

 

Yeah Rick - I also came to the conclusion that the fuel level probably isn´t my (main) problem. Checked with the service manual and it states to jack up the bike so the carbs are levelled when measuring with a tube.

Also searched the XJ-owners maillist and found recommendations to tube check holding the tube in the center along the side of the bowl - where the Hitachi-mark is on these carbs.

So probably gonna leave them (for a final bench check) and use the opportunity to check other things:

-free passage in enrichment circuit,

-redo the Clunk test and maybe just in case polish the slides - also on reinstallation use grease (I have silicone grease) to seat and seal the diaphragms

-look for replacement screws for the diaphragm covers (as some of the current ones don´t seem quite "trustworthy")

-last but not least: the tiny o-rings below the mixture screws were a bit worn; I don´t think they have problems sealing but the inner side on a couple of them had a small "edge" (see pic). Finding replacement o-rings could add yet another fun challenge, right :roll:

And, as I probably won´t be finished this week-end - should I consider disassembling the carb-cylinder intake rubbers (Installed them with hardened screws and new gaskets) and smear the gaskets with a bit of high-temp rtv? (I redid the start-spray test with the Carb-tune hoses attached to the vacuum-nipples - and still had a slight increase in revs. around two of the rubbers. As stated earlier I was able to turn all the screws 1/4-½ a turn - but just in case...)

So - with the fuel levels ok and eliminating false air intake - what could possibly go wrong 8)


CaptainKirk - Thanks; I pm´ed you..

 

The photograph of the teenie-tiny O-ring, with nothing else for perspective, makes it look like a worn-out, old front tire, snapped from a distance.

I doubt that it would be the culprit, looking like that, but ... it can't hurt to change them.

Did you find them in Standard Plumbing Supply or are they Special?

 

FinnogAngela must be your lucky time because I just ordered some orings for a set of carbs I am rebuilding. PM me your snailmail addy and I'll send you four.

 

Rick, haven´t found them yet - and then again ..

Blue: Thanks man; PM´ed you.

 

2. installation..

Including:

- new O-rings in the mixture screws (thanks, Bluemaxim..)

- Diaphragms seated in silicone grease

- new vacuum-nipple plugs

- new vacuum-hose

- new intake rubber gaskets with a light smear of high-temp silicone gasket.

Bike started right up, full choke - but wouldn´t idle when cold without choke. took off for a ride and discovered after 1 mile I had forgotten to push down #4 spark plug cap after the last colourtune attempt.

Pushed it down but still running rough..Home after 15 minutes I found out #1 pipe was barely warm, other 3 ok.

Looked at the plugs (still grey, whitish) and changed #1.

this time all 4 pipes ok warm after ½-1 minute - but still won´t idle without choke.

Gonna hook up the Carbtune tomorrow and check sync and mixture screws (all set out 3 turns).

I´m close, I think

- only shortcut I took was fuel level #4 a bit low (I hope my lazyness won´t fall back on me...)

 

Forums › XJBikes Talk › XJ Chat › 1980 Maxim runs but won't go!

Read this thread ...

I think you got the same trouble.

 

Here's a free YICS Tool ... too.

Forums › XJBikes Talk › XJ Chat › FREE YICS Tool's for EVERYBODY ~~> FREE!!! By: Rick Massey

 

Thanks Rick; yes - that sounds very similar to my problem.

I did clean the starter jet passages (watched the cleaner seep through the small hole into the float bowl) but might have missed the #1 - also sprayed through the siphon tunes but found it difficult to check whether all was "free flowing".

Gonna pull them the third time - and probably take the opportunity to replace the float bowl mounting screws with allen headed ones this time..

About the free YICS tool: Is there a substitute for Marvel Mystery oil - as I don´t think it´s available in Europe (WD40 or..)?

 

Something of a light Petro-product with properties that will withstand the heat without having dangerously low flammability should do the trick.

Brake fluid and fork oil come to mind .. I guess.

 

Ok - off for the third time (good practice...)

Found one or 2 (partially) clogged starter jet passages - right now they are soaking in carb spray. Thanks to "xjyamaha" for the tip on checking free passage with a pen light (see pic) in the thread: 1980 Maxim runs but won't go!

http://xjbikes.com/Forums/viewtopic/t=3 ... rt=15.html

All siphon tubes drips with carb cleaner when I spray it in the side-hole just above the enrichment valve seat - is this good enough?

Also found on the XJCD, in the article about cleaning the Mikuni Carbs, by Jeff "The Mountin Man":

"I've said this before -

Soak the pilot jets. Soak the pilot jets. Soak the pilot jets.

The passage size and shape makes it next to impossible to completely clean them otherwise. One small particle that is missed is very likely to clog them once more and any deposits left are a foothold for future deposits. When the pilots clog up, the engine will be next to impossible to start, idle, and will not sound right. Should you clean the carbs and end up with a "cold" cylinder, most likely something clogged a pilot jet.

For those that have never seen the pilot jets. Consider that after they are so clean as to look new, it is very hard to hold them just right and see the opening. A single grain of sand could stop them up. Get the picture? White-room clean and an in-line fuel filter after all the hard work."

And sure enough - the pilot jet in #1 carb had barely visible passage (after blowing in it none at all!) compared to the other 2 (my #4 has an abused slot so I´m hesitant to try and remove it - maybe tomorrow, if I can grind a screwdriver to fit..).

The 3 are now soaking...

(and I thought I was very careful cleaning and blowing with compressed air the first time....hm..)

 

Do a forum search for "douche dog snot." As I was asked last year, when you cleaned the carbs, did you REALLY clean the carbs?

All part of the learning experience.

 

I'm flattered Eblo! You remembered!

 

You're feeling better about getting this thing Purrin' like a liddle kiddy-cad ... huh???

Don't think it's all about those jets ... I want you to fill the Float Bowls and use that penlight to check on the level in the drilled-out WELL in the Float Bowl wall; too.

And ... the Tubes that go in there.
Nothing overlooked before buttoning these babies up!

 

"Those who don't' know history are destined to repeat it." I'm just trying to save others from the same frustration I put myself through.

 

Thanks guys;

Oblivion: I thread were others have threaded before me

There´s just no way but forward (as this thing until now sounds like a soar-throated dog..

Will do..

Ok; will try to find a suitable tool..

Furthermore:

The Pilot Jet with the chewed-up slot:



Should I try to get it out - or try to clean it and blow it through while sitting there (figure I then have to remove the diaphragm to ensure it won´t be damaged - I am not aware of the internal passages in the carb body yet)?

(I had it out in my first cleaning attempt - and I can still poke a small nylon bristle through it..)

 

If you are not going to be comfortable in your own skin for not removing that Jet ... you may use pliers to remove it ... provided you don't squeeze the poor little buggered Jet and break it.

 

Hm... I tried with pliers - but it´s difficult to get a grip, as I because of the rack have to go sideways in.

I think I´ll leave it for now; the corresponding cylinder is running fine and I won´t risk breaking it (that would be a major set-back).

Googled "Hitachi Pilot Jets" and the smallest size available (#38) was at http://www.motorcyclecarbs.com/Hitachi_jet_list_W40.cfm.

 

Have you tried a little heat from a hair dryer? I've been very successful with the screwdriver tapping method. As you already should have a perfectly shaped and fitting screwdriver handy for removing these jets, I'm going to suggest you fit it into the slot and, while it is firmly seated, tap on the handle like a chisel. Not too much but a sharp rap, all the while maintaining tension on the screwdriver in the counterclockwise direction.
I've had a great deal of success with this (only buggered one jet this way because I didn't hold the screwdriver down hard enough), give it a shot. Of course, it never hurts to have a replacement jet on hand before attempting this. #365 Hitachi, hmmm... is it really hard to find these? I'm sure we could source one for you and have it shot out to you inside a week. I'll poke around in my junk box, bound to be one somewhere.

 

Robert, I decided to let it stay, as I don´t have a spare. Gave it a little carbcleaner and some gentle pressure air. But if someone has an extra, I´m in the market

Motorcyclecarbs was the closest with their thirtyeight (don´t know why my last post insisted on putting a smiley instead of the 8..). A couple of others had 40 as the smallest.

Anyway, I´m at the (hopefully) final fuel level bench check - after spending most of the day getting one of the old (rounded) float valves out (succeded with a slightly grinded allen-bit whacked down as an extractor) - and cleaning the starter jet passages in the float bowls; must have sprayed, q-tipped, blown and pen-lighted them about a 100 times...But now they pass the "equal fuel level in bowl and siphon-tube well" test

Whev...and still perfect riding weather outside..

 

Succes! (sort of...)

Well I think I´m finished for now..

Installed for the third time - much easier than the previous two because of the sunshine and fairly hot weather; that had a remarkable impact on the softness of the airbox rubber boots.

Bike runs on all 4 cylinders - and after a final sync and the colortuning, runs nice and smooth and pulls like a champ.

Only thing is i had to turn out the mixture screws rather uneven to get the blue flame i settled on - ½-1/4 back from where it showed the last flicker of yellow. One I had to turn 5 full turns out to get the yellow flame and settled for 4½ turns. The others more "normal, about 3 to 3½ turn.

I figure I´ll go over them again when I get the Yics tool made.

Also: Choke is (still) not working. Bike won´t start with full choke..About1/8 choke gets it started but running very poor/uneven.

I have to "help" the idle the first couple of minutes otherwise it will fall below 500rpms and die.

Guess I´ll at some time has to return to the starter jet passages (which I spend hours cleaning, see above, next time I´ll take my time to let them soak betwen cleaning attempts) and the siphon tubes: sprayed carb-cleaner through them and watched it drip out of them but didn´t probe anything through them, I must admit. Will do next time, promise

So - I´ll live with the not-so-perfect starting for now and enjoy some riding and attend to the carbs again if the problem gets worse or the season ends - whichever comes first.

Thanks everybody for input and help - I´m enjoying the smooth ride 8)

Finally adding a couple of pics: One of my stuck float valve-extractor, made of a cut off allen-wrench grinded to make it slightly narrower at the end and making the edges sharper to get a better grip...

And the upgrade of my float bowl screws to SS Allen-heads - so I can adjust float levels if necessary and do other bottom end check-ups - such as replacing the bad-slotted pilot jet, if I find a replacement