Trying to tune my jets help please
 

Hi never owned a scooter trying to tune it when driving it when full throttle it jumps forwood I have an mpr exhaust and air small k& n airfilter. No air box wats the best jet size and why does it do that at full throttle or Evan like 3/4 it only seems to be able to go like 25 30 tops

Is it popping when you let off the throttle? Does it bog down when you give it full twist to fast? Most 50cc bike top out near 25, unless they have been worked. You need some type of air filter in it. Take off the carb, open the bottom. Should be four screws, that's the bowl. The main jet will have a number on it, engraved on the side. What size do you have?

I have a 150 cc china motor with a k&n airfilter and mpr exhaust.

Just took apart the carb and the jet that sits inside the carb is a 40. The longer jet with the screw says 108 on top

Hi
The longer jet is the one you want to change go larger as the mods you have done are letting to much air and not enough fuel
Your runnin LEAN
Get a few different size larger jets and do plug chops to fine tune
http://www.mopedarmy.com/wiki/Plug_chop
Being a little richer is always better then being too lean
Take care and ride safely
Yours Hank

Your the man hank thank you

I put a 140 jet in there same issue tryed adjusting air/fuel issue same problem Iam getting nervous someone sold me a lemon