05Firecat600SP

My boss had his 1998 XL blow up on him while he was using it. He told me it still ran but wouldn't go over 15-20 mph so he took it to a dealer. The dealer informed him he had an oil line fall off causing the PTO cylinder to go. They did a compression check too and it showed 0 psi in the PTO and the factory spec for the other 2 cylinders.

I have worked on 2-stroke snowmobiles and have done several top end engine rebuilds so he thought he would check with me to see if I would want to touch it. My only concern is if the crank bearing got really hot not having oil.

So the question I pose is do you think the bearing would be fine yet since the fuel was still going through the crank? I don't want to put much time into fixing this nor do I want to tear it down to the crank to check. Would it be a dumb move to just get the cylinder repaired and put a new piston with rings in it without checking the crank?

Ernest T

I'd pull the cylinder look to see how intact everything is. If there are missing pieces of the piston, etc., I think you have to open up the bottom. If it looks cooked but intact, you are probably OK with just doing the top end. This type of failure is fairly common, but you don't see it damaging the crank or bearings too often................still its possible.

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2008 Yamaha FX HO Cruiser
2010 Hurricane Sundeck 2100

Mannford

I have a Yamaha 1200 XLT (66V) with about 110 hours on it. Has Riva D plate to replace cat converter , wave eater kit, pump seals, otherwise stock. #3 cylinder skirt cracked on the bottom, and piston sides broken out. Cylinders 1 and 2 look excellent, very little carbon build up.

Is this a common problem, and what could have caused it? Happened suddenly at high RPM. I understand and am very careful to avoid lean conditions, which did not occur here. No evidence of oil pump issues.

Second question. I have gotten all apparent metal pieces from the piston out of the block. Unsure if I should remove the engine and attempt further cleaning, or just buy one new cylinder, two new pistons and do a top end only.

Mannford

Forgot to mention in my post that htis was not a power vavle failure.