OzVMX Forum

Clubroom => Tech Talk => Topic started by: RMJJ on August 09, 2010, 08:39:54 am

Title: Mikuni pilot air screw ajustment
Post by: RMJJ on August 09, 2010, 08:39:54 am

81 RM125 32mm round slide
I tried to set my air screw at the meeting today before the first race.
Was in a rush so gave up and just went out on the thing.

I fully warmed the bike up, got my mate to hold the throttle dead steady at tick over while I turned the screw. It made no difference whatsoever. I turned it  nearly fully in and 2 turns out from 1.5 turns standard position.
The revs did not change one bit. Nothing nadder didly squat happened.
What does this mean ? Too big jet too small jet ?

Title: Re: Mikuni pilot air screw ajustment
Post by: Stevo17 on August 09, 2010, 08:45:42 am

Hi RMJJ, possibly a too small a pilot, or could even be an air leak. Check for air leaks around reed valve, base gasket or crank shaft seal.  I had a similar problem and it turned out to be an air leak around the reed valve.

Title: Re: Mikuni pilot air screw ajustment
Post by: JohnnyO on August 09, 2010, 09:21:47 am

Possibly an air leak or a blocked passage in the carb.

Title: Re: Mikuni pilot air screw ajustment
Post by: micks on August 09, 2010, 08:09:39 pm

i have seen the very tip of the air screw break off in the carbie. someone had tighten it down to hard.