I'm fixing this 1998 Timberwolf, and when I got it, it was smoking, like a lot. So much so it's burning the oil. I'm still new at ATV repair, but I believe that is a piston ring problem, and if so, I would just like to rebuild the top end like I did with my LT80.

So, is there a recommended place to get an entire piston kit with bore? I am trying to stay away from Chinese cheapos, because of some previous issues I had with the LT80. Any recommendations are welcomed! Thanks!

 

As far as I know, there are no aftermarket kits for the Yam 250s, you may only need new rings anyway. The only way to find out is to remove the cylinder and measure it. If you can't measure the bore, piston etc, take them to an engine machine shop, they can check them and tell you what it needs. They can be inclined to tell you "Well the bore is within tolerance, but you need a new piston, so you may as well have a rebore and oversize piston" which gives them some work to do. Also be warned, it is a lot easier to fit a cylinder to an LT80 than an overhead cam engine, with the cam to re-time as you assemble. If you are going to do it, get a workshop manual.

 

Well, here is the thing. The smoke I noticed today some is coming out the tailpipe, but the majority of it is coming out the side in the tailpipe area before it gets to the end. It starts right up though.

Does that sound like piston rings still? I haven't a clue.

 

Find out where the smoke is coming from, oil leaking onto pipe, breather blowing oil fumes somewhere, or just a hole in the exhaust. We can't know, you can.

 

That was rather daft of me to say. Sorry.

I think this is probably the first thing I should do, before ripping an engine apart. Might not even need to if it's just something simple.

 

Found that right along the bottom seam of the muffler, it's totally split and that is where all the smoke is coming from.

Will work on this.