No vacuum on carbs 1 and 2.

I tried doing a carb sync on my 1984 xj750 Maxim last night with the Yics tool i made and Carbs 1 and 2 had no vacuum at all. Now I beleive that there was a problem with my YICS tool.

However just for kicks and giggles I put the YICS plugs back in and checked it again with the Carb Sync Gauge and still nothing on carbs 1 and 2. Carbs 3 and 4 worked fine.

We then switched the hoses from 3 and 4 to 1 and 2 to make sure it wasen't the sync gauage and still nothing.

Any ideas what to check or am I missing something.

 

Oh ya, just to add. The bike doesn't seem to be running to bad. Lots of pickup and not really ruff. Just a little hard to start when cold, it always does start though.

 

Probe down inside the tube on the intake, with a thin wire, or the red tube from WD-40. . .compare to number 4.
Problem is- - if there's a blockage, you would want to retrieve it,
and not just let your engine eat it.
That would mean pulling the carbs. :cry:

Just a thought- - are your boots smeared with rubber cement??
Some people smear them on the inside also, blocking the hole.

 

Way out of sync. 1 and 2 doing all the work, 3 and 4 closed pulling lots of vacuum.