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Crank Seal HELP!

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I now realize that I need to replace the crank seals in my bike as I am burning tranny oil. What exactly does this entail as I definately do not have the money to take it to the shop. I am definately mechanicly inclined i just dont want to mess something up or buy the wrong seal as I am having trouble locating the crank seals online. Any help about splitting the cases what seals i need ect. would be awesome as i was planning on racing this bike in two weekends. its a 2001 250 exc

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I now realize that I need to replace the crank seals in my bike as I am burning tranny oil. What exactly does this entail as I definately do not have the money to take it to the shop. I am definately mechanicly inclined i just dont want to mess something up or buy the wrong seal as I am having trouble locating the crank seals online. Any help about splitting the cases what seals i need ect. would be awesome as i was planning on racing this bike in two weekends. its a 2001 250 exc

Easy, pull off the crank drive gear. Then remove the gear and the collar. Careful not to lose the woodruff key. (might be able to do this with the clutch basket still attatched, maybe not) Now pull out the smal o-ring behind the collar. You will have plenty of room to get in there and dig that seal out. Plan on a new seal alonmg with the o ring. Inspect the collar for grooving. If its grooved, replace the collar. Dont drive the new seal in further than flush with the case of you will cut off the oil supply holes feeding the bearings. There is also a change the case gasket could be leaking. I just went though this same scenario in my grandsosn KTM 85SX. Replaced the seal and case gasket just to be certain.

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If I am burning tranny oil which crank seal do i need to replace the one on the cutch side, kickstarter side, or both? I dont have much experience with the bottom end of engines yet. and should the seals be roughly twenty bucks a piece?

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clutch and kick starter side are the same sides??? Its the seal at the right from of the motor that you are replacing, the end of the crankshaft. Be aware that the seal went out for a reason. This reason is commonly due to the main bearing wearing out and having too much slop in it. So you may find that the new seal leaks again quickly if this is the case. So check the bearing while you have it stripped down. If its the bearing I think you have to split the cases.

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I am getting my wet seal done again, it went just after 5hr riding???? I have one question, if the wet seal is gone and its sucking oil can this stop the bike from idling all together? the bike runs ok when on the throttle is open but as soon as I let go of the throttle the bike cuts out. I just got it back from the shop and the tuned it (it does run well when not asked to idle), they recon its sucking gear box oil and causing the bike to not idle. Does this sound right?

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I am getting my wet seal done again, it went just after 5hr riding???? I have one question, if the wet seal is gone and its sucking oil can this stop the bike from idling all together? the bike runs ok when on the throttle is open but as soon as I let go of the throttle the bike cuts out. I just got it back from the shop and the tuned it (it does run well when not asked to idle), they recon its sucking gear box oil and causing the bike to not idle. Does this sound right?

I suppose it may hamper idle. There is a possibility you have a case gasket leak. Did you recently split the case? After its warmed and cooled, try snugging down the case screws a smidge more if they feel loose. There is a few under the stator though. I had thsi issue. I split the case and replaced that gasket and the crank seals, just to make sure I hade it covered.

Did you replace the oring behind the collar? If you didnt, oil can get sucked under the collar. Most dont even know its there.

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the difference may be the way the motor changes its "pump" mode thru the rpms. A motor is a compressor type pump, sucks air in and blows it out. So at different rpms there may be different pressure pulses and with throttle closed, motor still turning, it cant draw the air thru the carb as easy as it can draw the oil thru the bad seal. MAYBE, just a guess. It can affect your idle too, but i would think the plug would be black and foul if left to idle for a while. As i said in my above post, the seal went out for a reason, it may be a bad main bearing. If it went out right away again then its almost certain the bearing is bad.

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