Rebuilding Time

[mybanshees2fast4u]

My 99 has a piece since the day i got it and probelms keep mounting up. First was aware the trans case was cracked so i bought a used RZ case assuming it will work. However i was riding my banshee for a couple hours and pop it blew up. The right side cylinder burned a hole in the piston right at the edge where the exhaust port is. So it is now time to replace the case and the top end, no probelm but why did it melt that piston and the other looks fine. The machinist at the shop I dropped the jugs to be bored at said that it leaned out and cause the motor to burn the piston. What could have caused to lean out? I assume the jets are right because the bike use to run fien with out burning pistons up before this happened the other day. Also do i have to use yamaha gaskets or can i use the cheaper kits that come with pistons. It is a stock motor and i may mill the head while i have it apart so i just wanna know if aftermarkert top end gaskets and aftermarket case seals seem to work okay?

[watkins]

Lean condition was most likley caused by an airleak.

 

Just order a Wiseco Piston kit and use the gaskets that come with it.

Edited April 28, 2006 by watkins

[Justintoxicated]

Hmmm,

 

How did you make sure the Cases Fit together correctly? Did they seal together perfectly? How did you make sure of this?

 

You could have had an air-leak, probably around the Intake Manafold, Check your rubber manifold and make sure there are no cracks in it.

 

Also check the Rubber boots that go from the carbs to the airbox (If you still have them)

 

Finaly check the gaskets behind the Reeds and manifold and replace them.

 

I would gues it was not caused by your jetting if it only burned up one side.

 

Do a Leak Down Test (find someone who can do it for you) to make sure everything is sealed up once you get it back together.

 

yor Not running a boost Bottle are you? Those things are known to cause cracks in the stock rubber manifolds/intake.

 

Replacing the chain once it becomes worn out will help keep it from snapping and smacking the case and putting cracks in it. May want to get a case saver for an extra piece of mind.

 

 

The Cases do NOT have gasket seals, it should be metal to metal sealed with yamabond between them. for the crank and other seals I purchased a seal kit I can't remember who makes it it was about $45.

 

I woudl replace all the rubber seals while you in there, as well as check your crank gap, and examin the shift shaft, it is discolored might was well replace that as well it is only a couple dollars.

Edited April 28, 2006 by Justintoxicated