carb sync or balance question

[scabber]

OK there around 154 people on line. how many have sync there carbs yardstick method ? Let's say for the first time on a what seemed like a good running bike.what did you find? Was close, spot on or sucking trans fluid down your intake boots. Next question what did you find the next after you had in sync. I'm just curious is it set and forget.

 

[retiredgentleman]

When I first did a sync, I did a rough sync with the carbs on the bench. I used a piece of paper as a feeler gauge under each butterfly. After installing the carbs and using the manometer with the engine running, I found that the they were very close, only out a few inches.

When I last checked with the manometer, they were almost spot on. So I would say they are close to being set and forget, but probably wise to check once a year.

 

[5twins]

Yes, you need to check them now and then, I'd say every 4 or 5K on the linked sets and every 2 or 3K on the dual cable ones. They shouldn't be off much but may have changed a little bit.

 

[scabber]

Thanks for the Replys I bench sync. mine first. on my bs34 carbs the center balance screw is real sensitive just touch it and not turn it and your moving trans fluid. Once I get them balanced they stay even if I blip the throtle to 5000 Rpm. I was wondering if the vibration changes the sync.a whole lot xsleo balanced mine when we were rebuilding a couple of cranks. I road it all last summer and part of this lost a vacuum cap changed the screw did not notice the cap was missing untill I went to hook up the tube then it was too late to tell if had changed.

 

[kvanderploeg]

Set your valve clearances first on an unknown engine. Hell, check them even on a known engine. Bench sync the butterflies first like RetiredGentlemen said. Using vacuum to check is kinda bass ackwards, but starting with a good bench sync will help.

Kent