I have heard that motor cycle engines in quad frames don't mix, I have heard that the vibration will crack the frame.
Anyone else have heard this or have first hand info?
I have a spare CR500 motor and thought it would go nicely into a Cannondale frame.

 

Iv'e never heard anything like that. My buddy put one in a zilla frame with no problem. A gusset kit cant hurt and i dont see much of a problem.Nuthing like a 500 two stroke. not to much help, just my 2 cents. Good luck and have fun

 

the only thing ive heard about the cr500 conversion is that you need to use rubber bushings when make your enging mounts. i guess they have a horrible vibration.

 

The CR500 motor does not have a counterbalancer as do all dirtbike motors which is the reason for the harsh vibration although the rubber mounts may help (slightly).