Jetting

[cleanone]

We put a free flowing exhaust on my sons 90cc Kymco Mongoose, it's a four stroke, now it cuts out at wide open throttle. Should I play w/ the jetting (go bigger) or the air box? any ideas would be appreciated.
Thanks!

[maggiesboy]

sound like it needs a modification to the intake system. Either air filter, and or jetting changes.

[Samson]

Sounds lean to me. I'd go rich 1 notch on the needle jet and size up the main. Always better to work backwards from too rich. Save any potential damage a lean condition might cause.

Not sure what type of carbit has? If you can't find jets, you can buy a micro-drill bit set from Harbor Freight for like $20 and drill out the stock main. Be trial and error. Heard one guy say he over did it then filled it back in with solder and drilled it right the 2nd time. Might be worth a try.

[cleanone]

Thanks for the input!