Any one done a pitbike motor?

[Needmorehp]

We are thinking of a pitbike motor, not sure I heard GPX are the most durable? All up 4 speed.

Let me know of any results or mods to make it fit?

[azextreme]

it will bolt right up!

[Birddogg]

They are the most durable from what I've seen, but they were all mounted in pitbikes. The added weight and stress a quad chassis would subject it to would make me wonder if the tranny/clutch would hold together.

I just installed a 4-up transmission out of an 85 ATC70 into my CRF50, thicker gears than the old Honda CT and SL 70s had. The thicker gears and beefy auto-clutch that the old ATCs had leads me to believe Honda did their homework and realized that the typical dirt bike tranny wouldn't last in an ATV, even one as slow and under-powered as an ATC70.

The 4-up is a better choice. The 1dn-3up trannys have a nasty habit of dropping into neutral at the worst times. I owned a china bike for a short time, the first time I raced it, it put me in the hospital. It popped into neutral on the face of a third gear pinned tabletop, thank GOD it wasn't a double.

My buddy has a GPX in his Thumpstar pitbike and he beats the snot out of it. It's a decent running bike but it's not even a year old and it's already blowing smoke and I know the timing chain is shot just by listening to it.

It really depends what you're gonna use it for. If your kid is rough on equipment it's a crap shoot. If he's a little more chill it might last for years.

[woodsracer144]

if you do a pit bike motor and want to keep it cheap and strong i would have to say the motor that is in the sdg 110 mini speed is awsome! i have the bike and with a 10 inch rear wheel i do 50 and thats all stock... there a 3 valve most are 2 valve... there are some really spend motors that people put in there BBR KLX's and its like a 140 big bore or a 172 stroker or something like that if you want more information let me know.... if you want some specks on that sdg motor i have one can take some picks for you...

good luck!

[stauffracing#4]

i just had an ogm 140 put in my trx90 its not a typical bolt in you do have to cut and move things.but let me tell ya the bike rips my son can put a wheely in second easy.gotta get the exhaust to.