I've been trying to replace the water pump seals on my 2000 Scram 400 and I'm at the point where I have to remove the left handed threaded crown nut on the crank shaft. I've even have the special socket needed just to remove it, but I can't seem to find a good way to stop the shaft from turning while I try to break it loose with the socket. I've tried using the bolt that screws into the shaft on the oposite side of the engine that the crown nut is on but it almost got stuck in the shaft permanently as when I removed it, you could see where the end threads were very close to being ruined. I've already sprayed the crown nut down with PB Blast numerous times, but that bad boy is on there tight as hell. Any ideas before I bring it down to the dealer to have them remove it? Thanks again.

 

If I'm thinking correctly you are taking off the 6-splined nut on the right side(sitting on the machine)? I changed the crank seal and water pump gaskets about a year ago on my 400 and it was a REAL PITA messing with that seal but I took off the clutch cover and slid a long pry bar through the primary and down thru the floorboard and used an impact after I broke it loose with a pipe and a 1/2" ratchet. IF i'm thinking about the same nut you are.....

 

Yes it's the same one only I have the engine out of the frame and I already have the primary off therefore I can't do it the same way you did yours. But I thank you anyway. Anybody else have any ideas?

 

I've always used an air impact with the special socket and usually no problems. If you get a tough one use a little PB Blaster along with a torch. If you can't stop the crank from turning, you can do what we had to do on the water craft and slowly insert a nylon ski rope into the spark plug hole as you are turning the crank until it locks in and stops. This was the only way to remove the drive shaft couplers when you had to replace em and we never damaged a piston or rod!! OPT

 

Every time I've done it I've had the primary clutch in place and used it for leverage, you might be better off to put it back on long enough to get the spanner nut broke loose. Then you can get a bar through it to keep it from rolling around on the bench while you break the spanner loose.