Carb synch issue

[crocktherock]

I've been having issues with a rough ride and decided to rebuild my carburetors.  They're all installed, new jets, same pilot screws but it's running rougher than ever.  

Thought about possible air leak so desmogged (thanks red eye).  

I want to reset my pilot screws and started with a carb synch.  The right side - 1,3,5 are fine, the left side, not so much.  They all read 34 cm Hg except #2 which is stuck at 10 cm Hg.  I cannot seem to raise #2 no matter what I do.   Bike is popping and I can't properly set the left cab bank - #4 and 6 are within range of the reference carb but it seems to affect the idling of the bike when I try to set the left side.

I checked for air leaks at the intake and none, could it be bad compression?

[Pete]

Could be and it will not hurt to check.
Could be valve lash not adjusted properly.
But it sounds like more than one vacuum leak.
Check everything for a vacuum leaks somewhere.

[Chrisj CMA]

I did a carb sync on a friends bike.  He had the carbs WAY out trying to compensate for massive vacuum leaks he created.  First I corrected the vacuum leaks.  Next, I started the sync.  Each carb I dialed in to the base carb the idle went down and down and down.  I thought I was going to run out of adjustment but I kept at it.  I had to turn up the idle after every two carbs adjusted.  Finally when I got the last carb adjusted, the bike died.  I turned up the idle, restarted the bike and then fine tuned the idle to 900 and it ran PERFECT like a fine watch.

Hope that helps

[Roidfingers]

 O-ring? Also make sure you are blipping the throttle between adjustments and keeping your idle set to 900. Every adjustment on any carb. Will make it change. Also confirm that the enrichers are all seating the same. Or unseating.

[crocktherock]

O-ring? Also make sure you are blipping the throttle between adjustments and keeping your idle set to 900. Every adjustment on any carb. Will make it change. Also confirm that the enrichers are all seating the same. Or unseating.

Do you mean pilot screws when you say enrichers?  If so, when I reinstalled the pilot screws, I put the spring, washer and o-ring on the pilot then screwed it into the carb until it lightly bottomed out.  I mistakenly backed the pilot all the way out of carb #2 (my problem child) again and the rubber o-ring was still on the pilot instead of being seated in the carb.  I didn't think this was a problem, please advise.

[97BLKVALK]

When referring to the enrichers he is talking about the choke.  There are 2 slides one on each side of the motorcycle that are linked to your choke lever on the clutch side of your handlebar. Please make sure that all of these when pulling back the choke open and close at the same rate on each carburetor.

[Jersey]

During Rebuild did you vacuum test the Air Cut Valve's (p/n 16510-MAL-600)?  During my recent rebuild I had the same symptoms as yours and discovered one of these valves had failed.  Interestingly enough, the propane test did not reveal this issue as the failure is internal to the air-flow chambers within the carb.

[crocktherock]

During Rebuild did you vacuum test the Air Cut Valve's (p/n 16510-MAL-600)?  During my recent rebuild I had the same symptoms as yours and discovered one of these valves had failed.  Interestingly enough, the propane test did not reveal this issue as the failure is internal to the air-flow chambers within the carb.

I didn't, and I suppose it could be the tubing or the valve itself?  I don't suppose there's a test for that while it's on the bike that anyone knows about huh?  I do get quite a bit of popping upon deceleration but put that down to the missing reed valves (recently desmogged) and the pilots needing adjusting.

I think I'll try the following in this order (easiest first):

1. recheck for vacuum leaks with carb cleaner
2. test cylinder compression
3. pull the carbs and check the air cutoff valves.

[Pete]

Good plan.