Starter valve sync problem

Trying to sync the starter valves and have run into a slight issue

Managed to sync 3+4 ok but no 2 is causing problems. Can turn it easy enough but it doesn’t seem to alter the “sync” for that cylinder. Any ideas on what the issue is and how to solve before I start stripping


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Have a read here if you haven't seen it before.........
https://www.vfrdiscussion.com/index...r-last-22-years/&tab=comments#comment-1111811

Have you got your idle speed at 1200, and if it changes with adjustments to a starter valve, you should re-adjust to 12oo before moving to the next one??

 

Many thanks, had seen and was using that as a guide. Problem I have is when I turn the screw to adjust cylinder 2 I get no change in the vacuum reading so wondering where’s the best place to look first to resolve this

Btw excellent hyperlinked post, many thanks


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I haven't done this, but perhaps others more experienced with them can comment...... do the starter valves need cleaning? Readjust #1 slightly to get you in range so #2 can be equal?
Have not tried, but on other bikes, shoot a little carb cleaner in each vacuum hose to flush any potential build-up?
See service manual page 5-65........

 

If the starter valve does not change the vacuum signal then you may have a leaking vacuum hose from the back of the starter valve to the intake port. Is the vacuum high or low on #2?

 

Vacuum is slightly (about 20mmhg ) lower, I’ll have a check of the hoses


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I'm pretty sure that all of the vacuum tubing is 5 or 5.5mm id; might be wise to get stock of that on hand and replace the whole lot while you are there.

 

My moneys on Terrys answer, the vacuum tubing. I had the same problem and it was the one that goes to the one way valve. It was split so i pulled the throttle bodies and replaced the lot with tube I got from a local motor factors, also swapped the thermostat while I had access. Alot of work granted but I dont have to go in there again.

 

Decided to send my baby in to have them look at it rather than tackle it myself before the riding season starts. They found a vacuum pipe off a non return valve and 3 of the 4 rubbers connecting the throttle bodies to the engine were letting by. Not a hope of getting that balanced, all sorted now


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Thanks for posting the findings Chris. Makes it easier for the rest of us in fault-finding mode.