I recently purchased a 2004 Yamaha Bruin 350 4x4. When I got it, it was not running. I rebuilt the carburetor, and got it running quite well, only to discover it is burning oil. A lot of oil. It burns at idle, and all speeds above. Piles of blue smoke.

The bike doesn't have a lot of hours on it, but it was very abused and neglected. I also noticed there was a lot of cam chain noise, so I pulled the tensioner. I found the tensioner to be fully extended, so it looks like the chain is shot too.

After I get the head and jug pulled, I plan to hone and re ring it, or have it bored, depending on what I find. I also plan to replace the valve guides and cam chain.

Now, to my questions. I have been in bike motors, but never an ATV. Can I pull the head and jug with the motor still in the bike?

Are aftermarket parts OK, or am I best to use OEM Yamaha parts? Specifically gaskets.

Are there any parts related to the cam chain I should replace as well? Guides, rollers, or anything?

 

yes you can remove the cylinder and head with out removing the engine.i would use oem parts unless the part you need is crazy high some of them are.make sure you check the outter cam sleeve the oil cleance is tight.