Topic: It has begun!!! Another 550 top end rebuild

[Adam_F]

Sounds like a possible vacuum leak that is opening up with heat.

IW

Out of curiosity... where would a typical vacuum leak be coming from?  I've checked the airbox to carb boot a few times.  Any by checked... I mean retightening the clamps.  How would I go about checking for a vacuum leak?  I just attempted to re synch and everything was still lined up proper...  As I mentioned... it will idle, then all of a sudden the idles just drop and the bike shuts off.

Any guidance is greatly appreciated.

Thanks!

[Adam_F]

Searched around and learned about the WD40 trick for diagnosing leaks.  I succeeded in getting WD40 everywhere, haha, but couldn't tell if it was really making any sort of difference in the RPMs.    Definitely didn't keep the bike from stalling out

[Adam_F]

So, I bit the bullet, woke up early and decided to tackle my carbs (069a) today.  I've been hesitant to do carb work for some reason, but I figured that its about time I learn my way around them.  After reading around on the forum, I decided to leave them on the rack and just work my way through each one, one at a time (no soak either).  So I went through and cleaned every jet and orifice.  The carbs were actually really clean inside, with no varnish whatsoever.  Then I got to the emulsion tubes.....  Check this guy out 



Filthy!  Soaked all the brass parts in carb cleaner and went at all the little holes with a guitar string and air compressor.  I also found out that my float in carb 4 was off a few mm, so I adjusted it back

Bench synched 'em and reinstalled on my bike.  Took it for a spin up and down the freeway.  Things are dramatically improved.  Not perfect, but much better.  It will now hold idle, but still gets a little chattery around 1200 rpm, as if its gonna stall out.  Almost as if its fuel starved for a split second.  Or maybe even like a cylinder drops off then fires back up (but there are no other signs of cylinder not firing like gas, cold pipes, etc).  Hard to say and I really have no idea.  Either way, its running better and rides great (no more stumbles off idle).  I still need to do an actual vac synch, so hopefully that helps with the idle.  My air filter is relatively new, but I'm gonna go pick up a new one so I can properly tune everything.

Either way, feels good to know that I can clean my own carbs when needed. 

[calj737]

A proper vacuum synch will really a whole other level of improvement, as well as possibly resolve the clattering.

Do also check your cam chain for proper tension now that your bikes running well. Often overlooked, always needs to be right.

[Adam_F]

A proper vacuum synch will really a whole other level of improvement, as well as possibly resolve the clattering.

Do also check your cam chain for proper tension now that your bikes running well. Often overlooked, always needs to be right.

Thanks!  Took me all day to clean the carbs and reassemble everything.  By the time I had it running I was too spent to do the vacuum synch, but I'm definitely panning on it.  I just readjusted the valves and tensioner a couple days ago, so that's all good.