Seems I have a problem with idle.

Re: Seems I have a problem.

Been there, done that, fixed it.

Yes, they did. The carbs were torn apart to the last screw and seal and cleaned ten different ways. I actually took the bodies to a shop to get them into an ultrasonic washer.

 

Re: Seems I have a problem.

Hm. Dunno. Perhaps one of the big guns will chime in.

 

Re: Seems I have a problem.

Check all your Boots. Then you can also do the paperclip sync. Remove carbs, open up idle speed till you can fit the clip in between wall & butterfly on I believe#3 carb. set all the rest of the carbs using clip under each one starting with #4,then #2, then#1. This should get you in the ballpark. After I did this I also used my vacuum sync tool I used on my multi carbed cars. It worked for me & this bike is gotten me lots of miles with no issues. also make sure that the floats are also not rubbing the sidewalls of the float bowl

 

Re: Seems I have a problem.

6,000 rpm's!

For the Plant to make 6,000 rpm's ... the THROTTLES have to be OPEN.
Have to be.

Not a small Air Leak.

BIG Air getting in!!!
Main Jet supplied Fuel.

I would suspect Cable-related or Linkage-related issues.

Handlebar Control loose.
Cable not anchored and pulling.
Choke and Throttle Cables errantly swapped.
Throttles stuck open.
Linkage problem.
"Something" keeping the Throttles wide-open.

P.S. You DID put the Plug for the YICS Passage back-in, ... right???

 

Re: Seems I have a problem.

And the amount of resting rpms is twice what you started with that should be a clue to you. It was running up to 3k now 6k-that is about 70% throttle averaged across your carbs. So back up and realize what must for sure be happening. The cause is yet TBD but the result is your butterfly's are opening and your CV pistons are lifting, or most of them are at the very least.

Maybe chasing a dead end but when you say 'cleaned 10 different ways' what do you mean?

 

Re: Seems I have a problem.

When Carbs are taken off, cleaned and put-back on, ... it is not uncommon to wedge the Linkage Cable Attachment under the back-side of he Head.

 

Re: Seems I have a problem.

Sounds like you havent really tried much of anything
Throttle shaft seals
Especially since you broke the rack.
Bench sync.
Set air fuel mixture screws to 2 1/2
Install
Spray carb cleaner on intake boots, listen for higher revving.
Spray on Throttle shaft seals, listen for revving
Spray on Intake boots, listen for revving.
Youve got an air leak
-Chris

 

Re: Seems I have a problem.

Good point Rick.
I've done that once before.
Only once though. Caught the mistake when I went to install the throttle cable though. "Oh. You shouldnt be here"

 

Re: Seems I have a problem.

6-Thousand Revs!

Ain't no Throttle Shaft Seals or some-other minor Air Leak!

The Throttles are OPEN
MAIN Jet Fuel entering Combustion Chambers.

You're closer to the Red Line than you are Idle.

 

Re: Seems I have a problem.

As above. You have a cable hang up or similar. This is not a cleaning/leak exercise.

 

Re: Seems I have a problem.

You sure you didn't simply mix up the throttle and choke cables, or the throttle cable has maybe jumped loose from its perch at either end? The motor cannot run at 6K without the butterflies being open, and that is a mechanical function.

 

Re: Seems I have a problem.

Big guns or small peashooters, the answer seems to be the same either way. Maybe I'm not so daft

And no YICS blockage would INCREASE revs any way shape or form :?

 

Re: Seems I have a problem.

FWIW .. have had the same problem with torn up yics tool seals..went back to stuffed with oily rags and the last time i synched the carbs ended up with a high idle when at running temp' , about 500rpm high so i did it again and it was right. Either you got th sync' wrong or it's a mechanical fault, for that many revs I'll go with mechanical fault as well.

When putting th carbs together after cleaning / seals etc did you make sure they were all lined up on a flat surface as you tightened the rail? that they mount together on and that the springs on the adjustment screws were all sitting properly. When i did mine i got a spring sitting wrong somehow but noticed before putting them back on, luckily.

 

Re: Seems I have a problem.

Throttle moves properly. Although, this did happen after I put the tank back on. Sigh... I'll pull it off again and see if it pinches anything.

Well, I'm sure I tightened SOMETHING on both sides of the engine... Yeah, I'm confident I did.

Taken apart to the last screw, dipped in chemical cleaner, brush bristles inserted into passages, ultrasonic cleaned at a shop. Jets cleaned separately in Chemtool. Verified light through them.

Look further up this thread.

Brand spanking new.

Done.

Done.

I'm sure they are not mixed up. The choke cable moves the valves, not the throttle.

As for the throttle cable, it seems to be moving properly, but since this happened after I put the tank back on, it's worth a look.

The second time around with new rubber seals I oiled the tool before inserting (that sounds seriously dirty ), made things much easier.

 

Re: Seems I have a problem.

 

Re: Seems I have a problem.

I have the exact same issue with my bike.
Bike runs buttery smooth until it reaches operating temperature. Then it will either spontaneously rev to 5k or if you blip the throttle it will stay at 5k.

I pulled the carbs off and rechecked EVERYTHING twice and it still has the problem. Ive recently pulled them off again and done every check for the umpteenth time, though I havent gotten around to reinstalling them and trying again.
Carbs ultrasonically cleaned. Pistons passed the clunk test on 3 seperate rebuild sessions, I even polished theis last time. All manifolds meticulously checked for vacuum leaks. Throttle shaft seals replaced, floats set, carbs synced with a manometer, shims done but I may change them around again.


The throttle does not need to be open to rev to 5k rpm at idle, and none of the vacuum piston are opened up when the problem is occuring(i ran it without the airbox last time to check this). We are talking about a totally unloaded engine not a motor in 5th gear crusing down the freeway. 5krpm only takes a few % throttle when in neutral.
Having the YICS tool in doesnt effect the problem.

 

Re: Seems I have a problem.

for whatever reason your only running on 2 or 3 cylinders,your idle speed is adjusted to 1K with missing cylinders. then when it gets warm the rest kick in and away go the RPM's.
your bad cylinders are probably lean when it's cold and close enough as it warms up.
when it's cold, start it up, and see which pipe stays cooler the longest.
look into the enrichment circuit maybe
maybe turn that mixture screw out,see if that brings up RPM's, evenness across the carbs doesn't matter
get some new plugs.
sync doesn't really care if the cylinders are firing or not

 

Re: Seems I have a problem.

Pulled off the tank, verified throttle cable is OK, verified spark on all cylinders.


And then it wouldn't start. Just cranked till the battery started dying.

I'm starting to think this bike is haunted.

 

Re: Seems I have a problem.

Alright so run us through the symptoms again. Hard to start, then idles at 6k? Anything else? How are those plugs? If you get it started see if one or more pipes runs cool.

 

Re: Seems I have a problem.

Good point, I'd have to say this is a distinct possibility if nothing mechanical is opening the throttle on you. It can be hard to detect even a 2 cylinder misfire on these engines (ask me how I know!)