I found one, I've thought bout getting one before to put in a dirt bike.

Good idea? i have no clue.

They say it turns over, they dunno if it works since it was removed from the snowmobile.

 

dirt bike idea? dunno but id swoop it

 

It can be done heres my current attempt not a dirt bike though, Ive just fitted a tiny rhf3 turbo charger to it, so far I have only made up the exhaust manifold, Im just waiting until pay day to go and buy some aluminum so I can make up the intake manifolds, and I am still working on the oil system and the fuel pump reg etc still has to be fitted to the bike, the engine is a sachs km3 lawnmower engine and has been periphial ported. You can see it running normally aspirated on youtube at http://www.youtube.com/watch?v=dOsCUtEE_W8