bogg'n Down

[michaeleakin]

Hey guys,
I had a bbk (72cc) on a chinese scooter. After it gets warmed up, an increase in the throttle boggs it down, especially from a start (red light). I run 93 octane, it idles really well at 1200rpm's. Iwas wondering if failure to adjust the carb properly is the culprit or what. Any insights on this problem would be helpful.

ME

[jmkjr72]

my bet would be your contra spring in the rear sheve is weak
after it heats up it will shift the rear sheve too fast

does your trans cover have any venting if not i would add some venting when you replace the spring