How to Sync Carbs on Yamaha Two Stroke.

[G Anderson]

I thought I'd start a new thread. I have a SycPro carb sync tool and was going to tried to sync the carbs on a 1998 40 Yamaha two-stroke. I have to take the oil tank off and move it ahead to get at the vacuum hoses. My question is can I just take the vacuum hoses off and hook up the tool or do i have to tee into them. The tool has the thread 5mm and 6mmin adaptors for the newer engines as on the newer ones you thread in and the vacuum lines all stay connected, but on the older two strokes this option isn't available.

Appreciate any and all ideas.
Thanks Graham

 

[99yam40]

I have not seen any vacuum hoses to each carb on those 3 cylinder 40 motors

 

[G Anderson]

I am assuming they are vacuum hoses. Looking from the rear they would be on the right side or the CDI side. There are three 1/8" rubber hoses running from up on the sides of the cylinders and they go into the manifold between the carbs and the block. They are shuffled a bit, in other words top cylinder hose goes into middle, middle goes into bottom etc. They could be some sort of vent or something but they looked like vacuum hoses. I can try to load some picture if that would help. Tks

 

[99yam40]

sounds like the crankcase re-circulation lines , they should have check valves in one end of each

They are not vacuum lines