Carb sync question

Just had carbs cleaned and they were sync'ed at that time. Just checked valves and all intake valves are in spec, and 3 exhaust valves were slightly tight and one was a slightly loose. Will the carbs need to be resync'ed after re-shimming the exhaust valves? Seems to me that the sync would be mostly based on the intake valves?

 

Sync is based on the manifold vacuum produced by a cylinder. The exhaust valves can affect that nearly as much as the intake valves.

You might at least check the sync. See how the bike runs; see if it returns immediately to idle and then idles smoothly or goes "lump, lump, lump" and most importantly, see what's up with your fuel economy.

The bike will tell you if it needs further attention. All you have to do is pay attention if it does.

 

Yep and if your bike has a YICS motor you will need a YICS tool also to do it right. Oh and if you had a bike shop do the sync and you do have a YICS motor chances are they didn't do it right to begin with. Mechanics of today don't know how to sync a YICS set up properly.
May want to put your bike type in with your questions and statements so that people can answer you correctly.

 

1985 XJ 700N with about 10500 miles on it.

 

Listen to the voice of experience.

OBD is one of the members who, after getting his bike back from a shop, had to do it again himself to get it right.

He'll be the first one to tell you it was worth it.

Plus, at 10.5K, I'll betcha $5 they didn't even CHECK your valve clearances even though they very much should have. You had to do that yourself, AFTER said "carb service" right?