I have a 2007 Raptor 50 that's doesn't have any compression, and I can't find the jugs or pistons online for it. So I was wondering if the jugs, head, and pistons for the 80 will fit the crankcase. If it's been discussed before or you can steer me in the right direction for parts for it would be greatly appreciated.

 

You should be able to get an oversize piston + rings from any Yam dealer, and get the cylinder bored to suit it. If you haven't already checked, you may just need rings, as they seem to wear a lot faster than bores on 4 stroke ATV engines. By the way, did you check valve clearances, that engine is notorious for loosing valve clearance and therefore, compression.

 

I will take a look. I have never dived this deep into one. Rewired a couple of Chi-honda clones, but nothing to mechanical. Any pointers?

 

Check the valve clearances before delving into the engine, you may not need to go any further.

 

agreed check valves
They get tight and will not start easy
Adjust valve lash and they fire right up

 

Checked the valves and turns out they where damaged by something internal letting go. Took apart the engine found bent valves and damaged piston. New piston, rings, valves, was the cure.