How long should the stock crank seals last? I've put 140 hours on my '00 KDX220 and I think both seals are going. Looks like I'll be doing a total teardown this winter. Also, has anyone modified the cases on their bike so that the seals could be replaced without splitting the cases? It shouldn't be too hard to fashion a retainer plate if there is room for bolt heads behind the stator plate and also on the clutch side (haven't been in there yet). It will be a few weeks before I tear into it but I'm curious if anyone has considered a mod. like this.
That is a really good idea if you can make it work. Were you thinking of drilling and tapping the case to hold on the plate? It seems that it would be quite difficult to safely tap the cast. Maybe I'm wrong though. If you do this mod I would like to see pics, you have me interrested now. I had to do my seals this summer and I did not enjoy splitting the case, although it went without any problems. Good luck with your seals.
I've put well over 250 hours on my bottom end and the seals are fine. I am replacing them this winter as well with new cases after a shattered piston destroyed my old ones.
So Kyle, are your cases toast or are you going to keep them for possible re-use in the future? If they're heading for the nearest dumpster I wouldn't mind practising the above seal retainer mod on them. Let me know what you think.