Crankshaft seal

[earl G]

On the way back home from xsse my seal started to leak. Oil on the boot
And gear shifter. Got about 75000 miles on the bike.
What's my plan ?

[3Phase]

You need to change the seal. Here's a thread with alternate seals and part numbers:

Leaking crankshaft seal repair

[bikerphil]

I have had that seal leak from it's outer edge before due to it shrinking. Cleaned the oil off real good with brake cleaner and with a finger, spread RTV around the gap overlapping to the engine case. That was 80K miles ago and still holding. It is easy to assume it is the inner part leaking that touches the crankshaft but that is not always the case. Might be worth a try because installing the proper seal (with metal lip) requires splitting the case.

[3Phase]

Right, what Phil said!

First you pull timing assembly off the engine so you can see where the leak is but if you can't find it, you'll have to put it all back together to run the engine until it leaks, then pull the timing assembly again so you can seal the seal or get another seal, if you see what I mean.

[bikerphil]

Another option is to put a glob of RTV on the oil weep hole and forget about it. BTDT

[3Phase]

I just replaced the left-hand seal a few minutes ago with the one I got from T.C., now it's sitting overnight to let the sealer cure before I run it.

I changed the oil and filter but the substitute seal from NAPA only had a single lip, it's not really a good crankshaft seal, it did a good job for what it was until I overfilled the oil and blew it out. Oops....

[TopCatGr58]

Hey Earl,

75K miles, I would suspect that the INNER edge of the seal has hardened, worn and letting it leak vs. the outer edge since the OEM seal has the large outer lip. It's not that hard to pry out with a screwdriver.

I replaced mine last year because mine also had similar mileage, and since I had the engine out of the frame, thought it was a good time to do it. I used the RED Gasket maker type RTV, but oopsed on the right one and clogged the oil return hole which caused it to build up pressure and blow it, that's why it leaked on me on my way home last year. The left one has held the whole time. I replaced the right one just before this years XSSE. I used 3bond this time instead and just enough to seal it against the crankcase.

With both of them, I then used/applied a nice layer of J-B Weld around the seal and the crankcase to help hold it in place. It worked and still hasn't leaked a drop. No splitting the cases to install, and like Scott said, get the good double lipped inner seal type that fits against the crankshaft.

Also just push the seal in so that it's flush with the surface of the crankcase, do NOT push in all the way until it bottoms out, that's too far. Scott recommended getting the BLACK version of 3bond vs. the regular gray version, supposed to be better with OIL??

T.C.

[3Phase]

RTV Sealants
https://www.pharosproject.net/uploads/files/sources/1828/1359733874.pdf

In a nutshell, there are three types of RTV formulations with different ways of curing:
Acetoxy (vinegar odor)
Oxime
Alkoxy

The acetic acid in the Acetoxy formulation etches and bonds really well to aluminum (like an engine case) but eats other metals.

I used the Permatex Ultra Gray gasket maker I got from MPittman at the XSSE rally. I'll have to look it up to see which formulation it uses but the black RTV is supposed to have better oil resistance. After I get the engine running I guess I'll find out if the gray is going to hold the seal in the case without breaking down in the heat and oil .

[3Phase]

I looked it up and the Permatex Ultra Gray is Oxime cure silicone, it's sensor-safe but I don't have any sensors to worry about, just the slightly weaker bond to the aluminum case and the unknown bond with the rubber seal itself.

[motoman]

I looked it up and the Permatex Ultra Gray is Oxime cure silicone, it's sensor-safe but I don't have any sensors to worry about, just the slightly weaker bond to the aluminum case and the unknown bond with the rubber seal itself.

Even though I have the OEM gaskets still in Yamaha packaging, I opted to use Permatex Ultra Grey on the machined surfaces of clutch cover, shift cover and oil pan. That was some 7yrs. ago when I did the 'tranny fix, and as of now, still not so much as a weep from those locations.

[3Phase]

Those are gaskets, Brant. The seal is supposed to have a retaining ridge to keep it from getting blown out of the case, the replacements don't and rely on the sealer to hold them. I haven't had one fail yet but there's always that time when you think it'll be okay, right before you get a boot full of hot oil.

[motoman]

Those are gaskets, Brant. The seal is supposed to have a retaining ridge to keep it from getting blown out of the case, the replacements don't and rely on the sealer to hold them. I haven't had one fail yet but there's always that time when you think it'll be okay, right before you get a boot full of hot oil.

NO gaskets used, was my point Scott. Anyways, hope it holds against rubber also. I'm sure you'll report if it doesn't. Least you'll have one waterproof boot!