zip70 said:4 stroke r u kidding 172cc's of pure 2 stroke mayhem, you will need to upjet your carb by about 10-20% for a free flow filter, or it will seize! ouch.. and making it look like a fifty is a v bad idea, the police wont notice but if u ever caused a crash, the insurance inspector would and youd be up shit creek without a paddle
so if i were you save up 125 insurance isnt much more than 50 insurance esp. if u got a years NCB
tom