questions / leaking crank seals?

Newby here looking for some help.
I have a 02 CR250R. The problem i am having is this... bike starts no problem but when i go beyond 1/4 throttle it bogs real bad and sounds like it has a rev limiter or as if were jetted to rich. I have just replaced the top end, cleaned the Pvalve, new reeds, 100% went through the carb, drained and replaced gas, cleaned air filter, replaced plug, and within last year i put on JD racing ignition and had bike dyno'd and have made no changes or mods since the dyno. I noticed when doing the top end that i have some oil on the crank as it rotates around. The oil is only on half of the crank as it rotates around. I am assuming this is from oil sitting in the bottom of the crank area which i think would be caused from a leaking crank seal (clutch side). Can anyone help with some input if this assumption could be correct and if so can i replace the seals (clutch and alternator sides) without splitting the case? Any suggestions are greatly appreciated.

It smokes like crazy for sure and i can't ride it due to the bog so tranny fluid level probably won't change a whole lot. Is there any way to know for sure whether it is the clutch side seal or the crank/tranny leaking without accually being able to ride it. Would a leak down test tell me which is leaking?

Thanks for your reply :bang: :bang: :bang:

Well i have finally got the factory service manual and the seals in so i can can fix this problem but first to respond to a few of the reply's that posted...

The puddle of oil that is sitting in the bottom around the crank is definatly not premix. It is very dark and very obviously gear oil. So i am almost positive that either my clutch side seal is the issue or the seal/gasket between the tranny and crank is leaking. As far as the carb goes... I have not only went through the entire carb once but i doubted myself so i went through a second time totally dissasembling and cleaned everything just to make curtain i did not miss anything. I checked the float height, seat, needle, jets, A/S, etc... The only thing i have yet to do is repack the scilencer but when i pulled it apart it was still in pretty decent shape. I did go and get the parts needed in order to put together a make shift leak down tester and as soon as i am finished writing this i am going out to the garage and going to do a leak down test and hopfully this will help me with my direction. I am still looking for some direction because i have never split the case before and i just want to make sure that this is the direction that i must go into. I was really hoping that i would not have to do so but it appears that i have no choice if the leak down test does not hold. Can anyone tell me if it is possible to replace the seals without splitting the case? I understand the correct way to do this here is to split the case, replace all bearings and seal, as well as the crank if necc. but i am sure looking for a quick fix that will by me some time. I only say this because the bearings are all good, i have no play or movement at the crank or even the rod. I think that my last ride i simply got it way too hot running wide open a bit further then i should have pushed it and this damaged the seal.

Well i will say that i do appreciate everyones replys and help. From the short time that i have been around here on DRN Forum, one thing is certain. Everyone on here seams to have a true desire to help others with the knowledge that they hold or the experiences that they have had. Thats Awesome!!! :cool:

Hopefully everyone is getting to go out and get some seat-time tomorrow as i know i would be if i could. It is going on four+ weeks now since i have got to rip it up and it is killing me.

Be Safe but Ride Hard.

GWS

From what i can tell it is just the seal (clutch side). When doing a leak down test, when i have a bit of air coming out the trans vent hose. So is this a safe assumption?

GWS