Hello! This is my first post on this forum, so thanks in advance!
I recently bought 2 KLX300r dirt bikes, the 2004 one is running and the other was sold as a parts bike and is a 2000. I am currently looking into the viability of fixing the parts bike, and I am interested in what the pros here think.
I was told when I bought it that the guy riding it was revving very high and they thought a valve shot out of the valve cover, making a large hole. I have removed the engine and valve cover and it appears that it was the "easy start" mechanism on the exhaust cam that self destructed and removed itself from the engine.

Now the good news in there was no metal in the oil, and most of the oil was in the bike which to me implies they shut off the bike right away. Also it has good compression.

My plan right now is to buy a new exhaust cam, and a valve cover off of ebay, and then attempt to JB weld the missing piece back into the cylinder head.


This is the piece I would JB weld in

This is the damage to the cylinder head

Ive actually found all the missing pieces of the "easy start" mechanism, one piece was in the skid plate outside the engine... There is some damage to a lob as well

Is this a viable plan? I am very much a novice with building dirt bike engines, but since this is a parts bike that I basically got for free I figure its a good chance to learn some things.

Thanks again!!

 

You could find a very good TIG welder to weld the broken pieces back on the head. Not seeing JBWeld as a good long term fix though. Otherwise start shopping for a complete head assembly, the cam caps are machined to match the head so you need the whole shooting match.