alright guys and girls......... you read the tital....... whats the largest and most powerfull motor your willing to stuff in a motorized bike ? i want to know what size 2 stroke is the largest most powerfull you would dare put in a bike and whats the largest most powerfull 4 stoke you would put in a bike and on a side note...... what would be your perfect motor ? for me the biggest i would go with a 2 stroke would be a yamaha blaster 200cc or a 150cc rotax or yamaha kart motor ! no way on this earth could you get me to put anything more powerfull than an old school air cooled 250R honda atv motor in a bike frame ! thats asking for your own death at 75mph !!!! now for a four stroke ... i know people use the predy 212cc but that motor is designed for industrial use and not realy a preformer out the box lol its large cc are misleading because a stock honda 70cc atv motor would smoke a moded preddy 212 almost all the time ! that being said the largest 4 banger i would ever dare to stuff in a bike would be a honda xr200 ! now my perfect 2 banger would be a honda cr85 2 stroke ! its small enough to fit in a gt lts frame and yet powerfull enough to send a bike flying up any hill and at any speed you wished ! my perfect 4 banger would be a honda cr50 style clone motor, only with a 150 cc big bore kit and all the mods you can toss at it lol that and a 4 speed auto ! i got a question.... why has nobody done a build with a 2 stroke kart motor ? there are pleanty of small 100cc 2 smokes that will fit bike frames with less modifacation and make more power than the preddy 212 ?