UFO main jetting for vm30s

[m in sc]

quck easy way to tell if pilot is too lean. rev bike up. if it comes back to a steady idle probably ok. if rpm hangs for a bit with the throttle closed, too lean. if it surges at idle, too rich.  you can usually get the pilot and airscrew super close in the shop running. -always- aim for over 1 turn out on airscrew, less than 2 out if possible. this is for proper circuit velocity

if by taking off your at 1/4 throttle or more, which i would guess is yes, the issue is in the needle. or airjet. but airjet mods will require mainjet changes. 

[waktaylor]

Thats what I was thinking. My main mist have been just on the edge of lean

I think my bike was seriously lean before I installed the ufo. After reducing the pilot for the ufo the carbs have no where near enough fuel flowing.

How do you drop 27.5 through the pilot and not have to increase your main unless your main was already rich?

The mikuni vm manual indicates the pilot adds fuel through the entire range. Is that wrong?

the pilot is always on, yes, but the percentage of fuel it supplies as the slide opens becomes proportionately much less . if the change in pilot requires a main jet change, your main was right on the edge or wrong to begin with. 

[waktaylor]

More good stuff, thanks again.

quck easy way to tell if pilot is too lean. rev bike up. if it comes back to a steady idle probably ok. if rpm hangs for a bit with the throttle closed, too lean. if it surges at idle, too rich.  you can usually get the pilot and airscrew super close in the shop running. -always- aim for over 1 turn out on airscrew, less than 2 out if possible. this is for proper circuit velocity

if by taking off your at 1/4 throttle or more, which i would guess is yes, the issue is in the needle. or airjet. but airjet mods will require mainjet changes. 

[waktaylor]

As if I needed more evidence of this, but I found more pointing to the fact that I am an idiot. I must have forgotten to torque the flywheel from the VAPE CDI kit and my timing jumped (mucho retarded I guess) so all this "tuning" was done with very incorrect timing. Now I know.

I removed the UFOs during all this mess and now that I have it running nicely I will swap them back in. What a ding dong.

[Hawaii-Mike]

Join the club! I think we are all guilty of making silly mistakes.