I have an extreme x 90cc atv. Motor is shot thinking of rebuilding the top end with a kit off e bay also kicked around the idea of swapping a 110cc 4 stroke instead. What's your opinion ?
Thanks

 

The 90cc "Minarelli" engine has a good reputation. It was used by Polaris, and is still used by Apache and one or two others. The CVT is also well regarded, the feeble kick start leaves something to be desired, but (if fitted) is only supposed to be a "get you home" device. I suspect fitting a different engine would be quite difficult, and usually ends up with a machine that isn't as good as the one you started with. So my advice is do the top end rebuild.

 

IMO the cheapo china kits available for 30 bucks are junk.
Get a good oem piston or a wiesco and have your stock cylinder bored.

 

Don't forget it is a "cheapo Chinese" engine Jack.