I have a 96 bayou 300 4x4. Its ugly, the plastic looks like crap, etc, but it was a good deal since I got it for pretty much nothing. My kid has run it for a couple years now.

he recently blew a ring, so I got a new piston and had it rebored- but now I see that the u-shaped seat for the front timing chain guide is broken, so that the guide will not stay in place.

I realize that this is totally redneck- but how neccessary is that guide? As far as I can tell, properly fixing it would mean replacing the entire left half of the crankcase, which would be both expensive and a little more involved than I feel qualified to do.

 

If the guide is held by the head and cylinder at the top, I would try it like that. Took a Yamaha Bruin top end down a while ago and found someone had missed the bottom mounting, but the top one had held it in place for several thousand miles. It would probably work without the guide, but there is a lot of "drive then overrun, then drive" on a cam chain and it would flail about a bit, shortening it's life. Other alternative, make a stud or bracket and drill & tap the case to provide a new bottom mounting for the adjuster.