Another Quick Carb/Idle Question

OK I've never touched a carb before but I got a hold of the Owners Manual, Service manual + addendum, and Haynes.

Bike was running fine when I purchased it. It has sat for about 2 weeks and I can finally ride it legally.

However, it does idle a little bit under 1k and wants to die and sometimes does.

Taking the POs word (for now) that the carb had some work done, is it relatively easy to just turn up the idle about 100-200?

I haven't check the above documents yet, but I was wondering if it is as simple as turning the idle adjuster screw if I just want to make that small of a change.

I have to practice and wait for my protective gear to arrive before out on the main road so I have some time to make minor adjustments as needed. (ie idle, peg movement, handle movement, fix non-blinking right, etc).

 

congrats on the new ride!

ok so let me be the first to tell you that when a PO says that they had some "work done to the carbs" that is never a good sign. And unfortunately, with bikes this old, when they go to the shop for "carb work" they usually just monkey with the air/fuel screws or do a bench synch. Rarely will you find someone who will clean and adjust the carbs like you will.

That being said... So when your bike goes to die out, is it warmed up? do you have the "choke" on or off?

It is possible to get the RPMs to rise by 1-200 if you simply turn the idle adjustment screw in. However, this will not solve a poorly synched carb, or a condition in which you are running rich.

What do you plugs look like? are they dark carbon, dark oily, white..? This can tell you a lot about if the bike is running rich or lean.

Finally, it would be my recomendation, to first see how you plugs look, and if you are not sure post some pics and the guys will chime in. If they all look perfect (which i dont suspect they will) you should just bite the bullet and pull the carbs and do a full cleaning and synch.

All the info that you need is on this sight and in your haynes. Let us know what you find, and we are here to help.

Kevin

 

congrats on the new ride!

ok so let me be the first to tell you that when a PO says that they had some "work done to the carbs" that is never a good sign. And unfortunately, with bikes this old, when they go to the shop for "carb work" they usually just monkey with the air/fuel screws or do a bench synch. Rarely will you find someone who will clean and adjust the carbs like you will.

That being said... So when your bike goes to die out, is it warmed up? do you have the "choke" on or off?

It is possible to get the RPMs to rise by 1-200 if you simply turn the idle adjustment screw in. However, this will not solve a poorly synched carb, or a condition in which you are running rich.

What do you plugs look like? are they dark carbon, dark oily, white..? This can tell you a lot about if the bike is running rich or lean.

Finally, it would be my recomendation, to first see how you plugs look, and if you are not sure post some pics and the guys will chime in. If they all look perfect (which i dont suspect they will) you should just bite the bullet and pull the carbs and do a full cleaning and synch.

All the info that you need is on this sight and in your haynes. Let us know what you find, and we are here to help.

Kevin

 

I can definately handle pulling plugs and taking pics for the forum.

How long should I warm it up with the choke open in 80F weather?

I realize I may need to do the carb my self this summer, but I rather get a few practice rides around my sub division first...

 

Maybe if someone is able take a pic where the screw is

 

sorry for the double post up a few, but my computer at work tonight is running at its peak efficiency... LOL

Alright so in the warmer weather, on my bike (xj550) in summer weather, i will have it at full "choke" for the start, my bike will fire up and stay at about 1500 rpms for the first 20-30 secs, then the RPMs will begin to go up. I keep turning the choke down as the RPMs go up until the enrichment is fully off, this typically takes 2-3 mins, and then she is good to go. Idles right around 1150.

now as to where the idle adjustment screw is. Assuming your set up is similar to mine, inline four. The idle adjustment screw should be located between the number 2 and 3 carbs in the back of the assembly (between the carbs and the air box). It is a rather large screw with teeth on it (to allow for a flat head screwdriver to be used to adjust- unless you have small hands then you can just turn it by hand) I am at work or i would snap you a pic now. If someone doesn't beat me to it, i will post one sometime tomorrow.

hope this helps

Kevn

 

FYI - I found that screw today (didn't touch it yet) and based on your description I found the correct screw!

I'll follow you warm up technique - Thanks

Linking Pictures of my Plugs - They probably need changing - I also probably need to do the whole carb but I'd like to ride it first!

1 - Outer Right - All Black
2 - Inner Right - 1/2 black 1/2 white
3 - Outer Left - Mostly Dark Tan
4 - Inner Left - Mostly Light Tan

 

Your right two are too rich. The others are in the ball park but a bit hard to tell from those pics. We need to see the business end of the plug up close but in focus. Maybe lay them all on a piece of paper and snap a pic.

valves checked?
Carbs synched?
mixes adjusted?

And first but unrelated to this rear brake shoes checked?

PO's lie alot. I see carb work in your future. Adjustments at a minimum.

 

I did not expect the PO to be 100% honest but it ran and did get out of the friction zone.

I have no idea or tools to check the above listed things yet. Had I know it needed actual work I would have been doing that the last 2 weeks

Anyways here's a youtube video of it low idle running and dying while I try to ease out of the friction zone. Yes I know grass may not be the best place but why move it, if its not going to run...

Bad Idle You Tube

EDIT: I can try in focus plug pics later... All I really wanted to do today was ride it around the block/sub division a little. SIGH

 

First lets get them in proper order.
The #1 plug is far left as you sit on the bike.
#'s 2,3,4 follow to the right in that order.
It's confusing to everyone unless you keep them ordered.
#4 plug (outer right ) is way rich
#3 plug (inner right) rich but no more then a small pilot adj.
#1 plug (outer left) looks more like the same photo as above
only shot farther away. at leasted the plug condition is identical.
#2 plug (inner left) in between the others on the rich side.

The first thing you need to do is learn all about your carbs.
where parts like pilot screws,sync screws, idle screw etc. And
you need to know how all these things work together to make the carbs
run correctly. We can guide you through what needs doing but under-standing is more then half the battle.
As for the current issue-find the pilot screws at the front of each carb.
Are they covered with a small cap (sits flush and may be brass)?
If not gently turn clockwise untill it stops. VERY VERY GENTLY! The tiny
o-rings WILL be damaged if you turn tight.
Then turn back out 2 1/2 turns each-be sure to make a small mark
on the driver and the starting point on outside of screw port.
that will give a reference to your half turn (s).
Warm the bike up, let idle 1 full min,pull plugs and check color.
If nice and tan or drk/grey then the're fine . if not get back with pics.
Good luck

 

Ok I can try the brass screw procedure. Did you want me to color check with new plugs?

I can and will learn my carbs was just hoping it wouldn't be a zero miles (or yards) riden

 

OK I think I found the Brass Pilot Screws
All 4 have a small black rubber boot on top of them.

I also grabbed 8x spark plugs from my local farm and fleet just to have.
I can grab better brand/type at AutoZone as needed.

I'll try to take better plug pics shortly. (As purchased plugs).

 

The brass piece with the fingers attached to the rod on it is the enrichment (choke) plunger and does not adjust.

Your pilot mix screw is down in that little hole next to it in picture #3 and on each of the other carbs. It should be a standard/straight slot head. It may be covered by a anti tamper plate in which case you can not see the head.

 

No cover plates that I see.
Guess I'm learning how to take tank off
Should I do any thing with the new plugs yet?

 

The tank comes off by removing the seat and the one bolt at the rear of the tank. Disconnect the fuel and Vacuum lines from the petcock. You'll see the bolt when the seat is gone. Then lift up on the back of the tank and pull back the tank should come off. You might need to wiggle it a bit. it sits on rubber donuts up from and has C shaped pieces that fit on the donuts on each side of the frame.

MAKE SURE YOUR PETCOCK IS ON OR RES. PRI will dump fuel everywhere.

If those are the correct replacement plugs (I don't have a cross reference chart) then you could check their gap and install them. The color will change on the old one's as well.

 

Tank off and even tightened cap attachment screw
From left to right pilots clockwise turns
2 1/4
Stuck and screw does not look good. Will try again after a cola
2 1/4
1

Will work on 2nd screw. Turn back as suggested and fire up with new plugs

 

Use mineral oil or machine oil to loosen them up and
do all at the same time.

 

2nd one stayed stuck.

Put all back together with need plugs set to nominal.

Now I can barely start it.
Full choke about 1100
Ease out choke dies. Sigh

Edit think I has 3 and 4 wires swapped

 

Not quite sure what you're trying to say.
Please re-read your last post and clarify.
thanks.

 

2nd from the Left (#2???) Carb pilot screw is still stuck (flat groove is in bad shape and maybe the threads also).

I accidently swapped plug wires 3 and 4 - Its better now

I adjusted the idle slightly (until can do real carb work) to get the idle about 1100-1150 (may hands are big but thin).

Engine is still cooling - Can TRY to take plug color pics in a bit.

Rode a total of 1.4 miles around my block.

Siting in the grass was definitely NOT helping me "walk" the bike as a released thru the friction zone.

Got into 3rd gear max and probably no faster than 30mph. But it was fun! I felt so insecure w/o my helmet - Its on order.

So my goal of at least putzing around the block was accomplished, but I think I definitely will be doing carb job sometime soon...

EDIT: Thanks all for the help so far.

I'm not sure any thing I did today made it better (besides turning up the idle) but I learned alot already

 

Mini Update:
Pulled Post-Adjustment new plugs
1 - Dark Brown - Tip of arc some metal showing
2 - Between 2 & 3
3 - Mostly white shaft - Tip of arc nice looking
4 - Still ALL black (even after turning up pilot about 1.5 turns earlier)

I'm not so great at taking close at up close pics. I'll try to load them from my camera later - Earlier pics were from my phone.

 

Does turning it up mean loosen or tighten the screw?

 

I tightened and loosened the pilot screws as suggested earlier - no more no less - other than new plugs

 

Up ...
Out.
Left
Not IN

 

No cut and paste of the tune by ear for this one Rick?

From you descriptions #2 sounds like it's good. Which is nice because you screw is stuck in there.

1 would be a little rich but better than being lean
3 a little lean
4 too rich

Search for Rick's tune by ear and try that.

 

3 and 4...
So assuming I JUST mess with pilot screws at this point...
Do I loosen or tighten 3 and 4?

I have started reading the Haynes but not had alot of time tonight...

EDIT: FYI I will TRY to do the carb the right way when I can but it will take alot of reading and tools and parts probably...

 

I would highly suggest putting the tools down and picking up the manual to read it.

I assure you a lot of your time will be saved.

Also read the three posts by rick at the bottom of his posts. And chacal's catalog would also help you a lot.

Getting things right will take time. Doing it quickly but wrong will take more time and more money, and will frustrate you.

One of ricks tuning posts is here, but you are far from ready for it yet.

You need to adjust your valves, sync, then tune. Probably with some other steps in between.

It seems like this is your first bike and I know you are excited but remember, "Smooth is fast, fast is out of control".

 

Yes my first bike and never touched a Carb before even though I have a Mechanical Engineering degree LOL.

I'm willing to do it right. But atm I also want to ride it just a little.

So far I stopped it from dying when put into 1st...
Its a small step...

 

Make sure your brake shoes aren't delaminated. Check your front brake pads. Check your master cylinder to be sure Safety is #1.

Get new plugs if you haven't already. Do a valve adjustment. Check your coils with a multimeter. I personally recommend new plug caps if you have the original ones, but others don't think it matters if the multimeter says they are in spec. Go ahead and do a sync. Properly! Then adjust your idle mixture screws. All this time you might have to be dialing in your idle speed. Just make sure your bike is well warmed up before you touch it.

And don't forget that your degree teaches you what stoichiometric is, not how to achieve it on a 28 year old, abused Hitachi HSC32.

We will teach you that!

 

Day7a1 - Most of what you speak is Greek atm... Eventually I'll do all that properly...

Front brakes look relatively new - Not sure about the delamination though

 

You're in too much of a hurry to hit the road.
Don't rush through things and make crazy mistakes that can cost you set-backs.

You are geeked.
I can sense it in your writing.
Get out of that mode of just aching to get it out of the garage and ride it.

Do what you need to do, ... first.

You ain't in a Race to win "A Few Laps Around The Block."

You are building and tuning to be safe enough to ride anyplace.

 

I'm absolutely, positively, sure that my Bike has 100% Original Factory Spark Plug Caps; and could not be more Fine Tuned if Yamaha sent-in the Racing Team to help me eek-out another 1,200 rpm's.

I treat them to a bath with Armoral that I brush-on them like I was putting Toe-nail Polish on perfectly manicured toenails of the PlayMate of The Month.

Why, pray-tell, should I replace perfectly good Plug Caps?

Because they, ... ???
What?

 

I agree I may be in a hurry to get on the road a little...

But I thought I bought a mostly smooth running ride.
Had I know it wasn't... I had 2 weeks I could have been working on it.

I'll probably clear out my bench in my shed and buy some of the basic supplies for working on the carb (currently reading the 9page post from Rick http://xjbikes.com/Forums/viewtopic/t=2 ... n+own.html)

Well I have probably a week before my helmet/jacket arrive - So I guess I have some time to do the carbs or at least try

 

What is "atm"? You keep typing it.

Did you take the front brake pads off? One side wears out a lot faster than the other. Do a search on this forum for delamination. You should not ride your bike until you check for it.

Keep reading. You will learn our "greek". And don't be afraid to use google to look up words you don't know.

 

ATM = At the moment...

Learn my greek

I play World of Warcraft and have been on the net for a long time

 

AATOTW acronyms are taking over the world ~~o(

 

Yes, Metal, just start with the plug color. Thats easy to do
and will give you conifdents to move on to more complex
issues.
Ok-drk brown to black mens Rich. Turn pilot screws in 1/8 turn
(clockwise)
Mostly white-lean ,turn out 1/8 (counter clockwise).
All white or new looking STOP. TOO LEAN MAY DAMAGE MOTOR.
Start all over at 2 1/2 turns out.

What day7 is asking is ,check to see if your brake shoes are
falling apart. Another use for the term DELAMINATE is when a
glossy hard plastic like surface has developed on the shoe.
These terms have been used for both conditions-coming
apart/hard,hot brakeing damage and can be confusing.

Once you get the hang of the pilots we can move on to more complex
items. You have the manual so read,read,read.

 

SLIGHTLY OFF ON A TANGENT - ORIGINAL POSTER.

So I'm still reading up on carbs and all the cleaning and tools and patience I'm going to need.

For someone as clueless as me, how can you tell if you need an immediate cleaning/sync'ing or just fine tuning till the end of the season (Fall in Chicagoland).

I'm sure the 1st thought out of everyone's head/mouth is going to be "just clean the carbs and you know its right".

That's fine and dandy, but how would a motorcycle/carb newbie KNOW he needs to work on his carbs/sycn vs. minor adjustments?



BTW (By the Way) I am 36 and never done more than change spark plugs/wires on a car (80's era). However, I'm smart and willing to learn and read and read and read

EDIT: I'm not saying I've never taken stuff apart and worked on them. Just never an engine - Similar idea - disassemble, clean, repair, adjust, reassemble, etc.

 

Really, the only clue would be a poor running bike.
If minor adj make it run like new then your done.
Watch for what other people with the same model/yr bike
and compare things like speed,gas milage,smooth idle.
Compare your performance to other bikes of the same or
larger displacement.
What your asking is learned through trial and error-sometimes
a lot of error lol-and experience.
stick to it, follow the advice of the many experts on this site.
THE BIGGEST, MOST IMPORTANT RULE TO FOLLOW IS
NO SHORT CUTS.
"short cuts make long delays" jrr tolkien.

 

What parts said... you can always try syncing/tuning (with a YICS tool or substitute) and see if it turns into a smooth-running beast.

First you should at least measure valve clearances. Not too hard to do, although you'll likely want to replace the gasket and donuts. I suppose you don't have to do that, but you may leak some oil.

After that you could also do a compression test to gauge overall engine health. Not hard to do this either, could rent a tester from an auto parts store, I would think.

Could save a LOT of time doing these two tests before fiddling with tuning.

 

Chaz - I'm definitely interested in the 2 tests you mentioned.

I'd still have to read up on both of those tests and see if autozone (or local napa???) rents the tester.

If anyone has specific forum links for newbies for those 2 tests, it would be greatly appreciated.

I didn't have a chance to make the slight pilot adjustments suggested last night. Maybe on Sunday. (4 was still way to rich, 1 was a little rich and 3 was lean).

 

Definitely. See Airhead Valve Adjustment with Pics and Compression Test which really isn't a FAQ but note BigFitz's succinct summary at the end:

My bike took more like 8-10 revs before it stopped rising, but it was pretty close after five revs.

 

Hey would this compression tester be sufficient?

Compression Tester at Farm and Fleet

 

That's the one I have, but mine has adapters that fit different plug sizes. http://www.northerntool.com/shop/tools/ ... _200329225 is more like mine. Just make sure it fits your spark plug threads. I don't have a 750 so can't say for sure.

 

I'll probably bring a spare plug with me to the store

 

When I got my bike, I just started going through all the items in the regularly scheduled maintenance list. The ones at 2500 miles need to be done, then 5000 miles, then 7500 miles.

You can assume that none of it has been done, so they are all due. You should try to do it all as soon as possible, but you should make sure air is in your tires and the cables are adjusted before you regrease the steering head bearings. I worry that you are all about making it run perfect now. You need to "not die" before you "go fast". There is more to a bike than the engine.

It also depends on your budget and what you use your bike for.

Good, Fast, Cheap...pick any two.

 

I realize now this may be a (fun?) project bike long term as I learn to wrench and adjust it.

The bike does "not die" any more as I shift into 1st. (Of course part of that is my too-quick clutch release SOMETIMES).

Going fast would take me a few days/weeks of practice anyways. (Still waiting on helmet & jacket to arrive - Legal or not I'm wearing a helmet in Illinois).

I don't expect it to be perfect - After all it is OLD - But I do want to be safe - Gonna check brakes this weekend before I putz around again. I know for a fact the right side brake caliper assembly is missing a grease fitting. I just keep forgetting to pick one up the last few days. Of course this may lead to another can of worms *nervous laugh*

EDIT: For a 1st bike and a SMALL/non-defined budget, my major fear is I'll spend more making it safe/right than I could have bought a CHEAP new bike ($4000-$6000) - But at least I won't need a mechanic for most things once I learn and have the tools

 

According to Chacal,

NOTE: NGK plugs that begin with the letter "B" are 14mm plugs. Plugs that begin with the letter "D" are 12mm plugs.

HCP1292 Standard NGK SPARK PLUG, BP7ES, correct for all XJ650 (except Turbo) models and all XJ750 models.

So you have 14mm plugs.

 

NO!!!! YOU DON'T DIE. YOU!!! I DON'T CARE ABOUT THE DOGNANM BIKE!!!! BE CAREFUL OUT THERE. MAKE SURE YOUR BRAKES WORK. LOOK AHEAD AND ANTICIPATE TRAFFIC!!!!!!!!!

GET THE MANUAL BRAKE CALIPERS DON'T HAVE FRIKIN GREASE FITTINGS!! THATS THE BLEEDER VALVE!

If I'm wrong I apologize in advance for yelling at you.

Ahem...The other theory is you can do something well, you can do something quickly, or you can do something for a low price. But you always sacrifice one of the three to get the other two. For instance, I used to take my truck to a mechanic that was rather inexpensive. Really really cheap. But he did GREAT work. Awesome mechanic.

But it took about a month to diagnose a transmission problem. Not even fix it, really, just diagnose it. But I didn't really need my truck.

Most people go for fast and cheap. That is why nothing is ever done well. If you do it yourself, you generally sacrifice fast. For these bikes, fortunately, and this is why I love them....Once you have the tools and knowledge you can get good and cheap, and pretty quickly too.

You won't spend $6000 making this bike safe. You probably should not have paid more that $1000 if your bike runs as it does. I paid 1/3 of the going price of a well maintained bike in my area.

To make it awesome, you might spend that, though. But you will have a very unique bike!! I know I do.

 

I thought I might have over paid a little - being inexperienced, alone and eager....

But it does have 2x new AVON tires - A new/newish battery - No tank dents - 95% seat quality (my opinion) - good looking front rotors (but need to check brakes this weekend) - it does start and go - All light work (except right front and it won't blink - another project) - clean title - and got it delivered by the PO

$1200 in Chicagoland via Craigslist - But it looked 1000x better than a previous '82 I happened to look at the same week that had NO battery, bad tires and looked like crap

I have bought a Cover, Battery Charger, Plugs, plate bolts - Ordered Helmet and Jacket so far - Plus all the legal stuff (title, plate and M-Class) and insurance - It does run - But I'm sure I can make it better with time, TLC and $$.

EDIT: I do like the classic look and semi-uniqueness of it - Some day I hope to make it pretty looking as well.