help a new dad out

[cujobell]

Guys , my daughter has a xtreem 70 with a pirahna 125 motor. she wants to start racing some and the gearing seems all wrong. 13 on front 43 rear. what should i change ? it came with a 16 tooth front sprocket but the chain wouldnt fit on all the teeth. any and all help would be great, even if it has to do with other things besides the motor. thanks Chris

[Ride1Rob]

You shouldn't go any lower than a 45. 47 would probably run pretty good. Also, what carb are you running. That itself will make a nice difference in how the bike lays the power down.