2004 KX65 crank seal

[Paul_B]

My son's 2004 Kx65 had the right side crank seal move into the bearing. this was first noticed as a metallic rubbing sound coming from the motor. I run 28:1 ratio pre-mix.

I replaced the crank bearings and both crank seals, put it back together and it seemed to run well, with the metallic rubbing sound now gone.

I took him to a local MX practice track and the bike seemed to be running really well. About an hour of riding later the noise is back, and even worse than before.

My questions:
Has anyone come up with a reliable way to keep this right side seal in place? What makes this seal move, is there high pressure on the clutch side, low pressure on the crank side, or some rotational thing that's making it move?

I'm thinking this time I might try some sort of setup to secure the seal in place with bolts.

Thanks,
Paul

[griffbones]

Is the crank out of true and shaking the seal loose maybe? I have never heard of this one before, don't you just hate these wierd quirks that never happen to anyone else! I thought that I was the only one that had these kinds of things happen them. I hope someone else comes up with a good answer for you and good luck my friend.

[Sledder]

It seems I've heard mention of these crank seals before. I think someone mentioned using 3 bond on that right seal when installing. We have an 04 and an 05 that are raced every weekend,practiced 3 times /wk and have never taken out a bottom end. I do hear of people having lower rod bearings go now and then,but we have not. I run Redline racing premix at 40:1

I have not had a 65 bottom end apart yet,so I have no personal observations that I can contribute. ....actually,I probably would have torn it down by now for preventative maintanence,but with all the stories of crank failures on kids that scream the 65's(my kid does)....I just seem to be curious as to how long it will go. We have done a few top ends on them,but that is all.

My youngest,that drives the 65's broke his foot on Sunday,he will be in a cast for a few weeks,so it may get rebuilt soon.If and when I do I will certainly pay attention to that seal.