Originally Posted by Slamnek 
If you can rebuild a 350 you can rebuild a sled motor. Sleds are easy to fix and a manual helps a lot. I dove into a CR125 motor a few years ago and since have rebuilt two sled motors and my CR250 three times. Only screwed up once and that was on my dirt bike this summer. I put the piston in backwards because i did'nt check my manual. 2 strokes are very easy to work on.
What he said^^^^^. Two strokes are easy, some of the electronics are a pain in the $#@, but the actual internals are pretty simple. Manuals can be bought at the dealership or online from most places like Dennis Kirk or Royal. Biggest things are take lots of pics if you are disassembling something or draw diagrams and make sure you have the right tools and knowledge (like dial gauge and knowing how to find TDC, etc.) But if you have rebuilt a 350, the principles are basically the same.