ok, i tore the top end down on the raptor. the piston was scored pretty bad on the backside, the rings were frozen into the pison, and the cylinder has some scratches in it. my question is, would that probably be from the cold weather i was riding in? or could it be that because of the k and n filter, it was running too lean? the thing about that is after i put the filter in, i read the plug, and it seemed fine. not too lean. would it be possible that if was running just a little bit lean, not even enough to show on the plug, that the cold air and the slightly lean mixture could have led to this problem? or could it be an oil pressure problem? i noticed in the manual it says there is an oil pressure check plate in the right side of the head at the end of the cam. is there a tool that can plug in there and measure the oil pressure? if so, where could i find one? thanks for the help guys.

 

if this is a stock bike and you have never been into it before I would say it is an issue with the flow of oil.

It is true that colder air allows for a denser air fuel mix and you should jet up for it, but usually running too lean will cause holes in the piston or at the least alot of pitting in it before it will completley fail and seize up. I would guess you lost oil pressure.

 

do you think that with using the recommended oil, that a 50 degree temperature would cause the oil to thicken enough to where the pump wouldnt be able to pump it? i've ridden it in the real winter up north many times, and i've never had anything like this happen before. the one thing i was wondering was when i first bought it, whenever i would start it, you could hear the oil pump kind of whirring for a little, then it would stop. if i remember correctly, the dealer said that was the oil pump priming the system. well that stopped happening about a month after it was new. i know the oil pump didnt just stop working because my top end would have gone out a long time ago. is there any way to test the oil pressure? a buddy of mine said he pulled out a little strainer from the bottom of the oil tank. could that have clogged up? there is no pitting or anything in my piston. just some minor carbon build up on my head and top of piston. im in a position now where i dont ever have any time to just start pulling stuff apart and figuring out the problem, so if you guys have any suggestions, let me know. thanks.

 

50 degrees is nothing, to worry about at all. I would pull the screen to see if it is clogged, but while the bike is running you can pull the screw out of the cam cover on the right side and it should be pupming oil, that is a quick check for pressure.

 

i was reading through the manual and it said to remove the pump, you need to pull the clutch. do i need to pull the clutch just to check the screen? the manual said it shoudl put out 9 psi at 1500 rpm. which seems a little low to me. but that's all i need to do is pull the screw out and see if it shoots out? i'll give it a whirl when i get the cylinder back from the machine shop and get the parts all ordered and everything. thanks for the help.