Jetting

[Chris280bigborr]

I have a 68mm piston kit with fmf pipe open air box stage two reeds mikuni carb when I'm in let's say 3rd gear and I smash the gas to make a jump it bogs down bad I have a 290 main in now is that my problem am I running it to rich and basically flooding the carb when this happens?? Also the tune is not as specified fuel air screw has to be al.ost 3 turns out for a higher idle then I adjust my idle screw to slow the idle down....it's been making a pinging sound and it can't be right?? Not knocking pinging is this all due to running rich and main jet size? Please words of knowledge please

 

[Larry's Shee]

Pinging (if it actually is) is caused by poor fuel quality or low octane.

What pilot jet do you have?
Clip position on the needle?

By “open air box” does that mean no lid?
Have you ever done a plug chop to check jetting?

Does it bog like that when on the flat?
A little dirty trick you could try while on a flat surface is to pull the choke out halfway as you stab the throttle. If it’s better then you’re lean. If worse you’re rich.
When experimenting it’s always better to try richer first.