I have an 88 xr600 would like to install xr650 engine. does it fit and how much work is this? also what is my engine worth? it is real nice low hour I pulled it apart after I bought it this spring. It still had the cross hatches in the bore but I did have it bored and installed a 98 mm wisco piston. I also put honda valve gide seals and a new timing chain. even tho it still had the paint marker on the chain. I wanted this engine to be bullet proof as I was going to keep it forever but now want electric start and one carb. any help here would be awsome. thanks Garry.