Help with 250R oil seals!

[xman2rman]

I have a question about the right (clutch) side crank oil seal. I've been tracking down leaks for the past week and got down to the crank seals today. I pulled the clutch and two gears from the crank on the right side and flywheel/stator on the left side. I tried to pressurize the case and it wouldn't. I could hear the leak around the crank splines on the right side. I reinstalled the gear set on the crank and pressurized to 7 psi. The left side seal holds but my leak is coming from the crank/gear splines on the right side. I have a new set of Tusk oil seals and there is one seal in the set that looks like it goes on the crank shaft itself, behind the splines and crank seal collar. There was not a seal in there when I pulled the collar off and I do not see this seal in the service manual or part schematics... only the case oil seal. The seal in question is the only beveled O-ring type seal in the kit, all the rest are rigid seals. Can someone please tell me if that seal goes behind the crank seal collar? If not, where does this seal go and how does the crank seal? The first pic is the seal kit, collar on top, then the crank case seal and the beveled O-ring seal that I don't know where goes. The second pic is the seal and collar in the case. Without a seal behind the collar, I can't see how the crankshaft and collar will seal??? I know this is a long winded post but I wanted to explain my issue as clear as possible. Somebody point me in the right direction PLEASE!

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[Dirtcrasher]

I will say this - if you read the manual - you would see that they want that crank seal either 4 or 5 MM further/deeper into the case.

The crank is tapered so the seal won't work until you set it in; This is the left side correct??

I don't recall that o-ring, but it has been awhile. Hopefully someone can tell you where that goes......

[xman2rman]

You are right and make a good point about the left/stator side. The crank is tapered and the seal rides on the crank. My problem is on the right side. You can see in pic 2 that there is a splined collar that goes over the crank shaft and into the seal. This does form a seal on the outer face but not on the crank splines.... How could this be and how can you seal the case like this?

[Mosh]

The beveled Oring is for the collar behind the sprocket on the counter shaft. Take the sprocket off slide the collar out and install the beveled oring on the sprocket shaft then install the collar and sprocket.

The collar for the crank seal on the right side has no other seal. Just the main crank seal that the collar slides into. It does not need a inner or second seal. The machine surfaces seal off against the crank and collar. Plus there is no area around the crank journal for pressure to leak once the big nut and drive gears are torqued down. The only way pressure can leak past the crank is through the ball bearing area, because the crank journal is pressed tight into the crank bearing so air will not pass through there unless you have worn crank bearings or crank journals..

So from your seal pic, left to right, top to bottom

The seal under you collar is for the kicker shaft
The seal to the top right of your package is for you outer sprocket shaft on the left side of the case.
The largest seal in your pack is your right crank seal
The small beveled one in the center of the largest seal is for the under the collar of the sprocket shaft
Then the lower right seal is your left crank seal behind the stator, and the little one in the center of that is your shift shaft seal.

And DC is correct..The left crank seal has to be recessed in the case. If you look at the back side of the stator there is a molded ring that protudes into the case up against the left crank seal a few millimeters.

[xman2rman]

Thanks Mr. Mosh, I got it! I was thinking today about the machined surfaces creating the seal in the center. I'll check them for trueness and clean them up if need be. I also thought about putting a little greese on the splines and collar to help seal it up, do you think that will hurt anything? Also, I do have just a tiny bit of play at the end of the crank in the right side, in the right bearing I'm sure. Possibally why that seal was leaking. Is a little play acceptable or should it be zero? Thanks for the help guys!