Blown countershaft seal on a WR450F?

Looks like I now can add a blown countershaft seal to the list of problems I've had with my WR450. At the end of my latest ride, heard a strange noise from the rear of the motor. Looked down to see oil gushing out from around the countershaft sprocket. Ordered a new seal and plan on replacing it this weekend but don't know if I've had any engine damage. I think it must have happened just before I stopped for the day since I didn't see much oil on the chain and rear of bike. So far, 3 woodruff key failures and a blown CF seal with less than 1000 miles - not a pretty picture. Anyone else had this problem with the 450 yet or am I the lucky one? :)

I have had several blown seals ove the years on my Thumpers. I have found that there is enough oil in the lower end to sustain the engine as long as you get it back to the trailer in a reasonable ammount of time.

Bonzai :)

Removed old seal today and found some strange things. The seal was in very bad shape with part of the rubber separating at the top - no wonder it was leaking like a stuck pig. Also, had some rather large chunks of silicone adhesive wedged between the seal and the cases which I assume caused the problem to begin with. The oil looked fine with around 1 qt still in the crankcase and nothing on my magnetic drain plug except the usual gunk that collects there, so I don't think I did any damage to the engine. Spent a good while cleaning the area to remove any dirt and smaller pieces of silicone around the bearing. I'm assuming this was caused by too much instant gasket that dislodged from some other part of the engine. Testing the bike up the street it seems to be OK with no oil leakage, but I'm not sure if I fixed the problem or if this is a symptom of a bigger problem. Anyone else ever seen anything like this? Any feedback is greatly apreciated. :)

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