GS1100 crank end oil seal leak, again!

[J Paster]

I would appreciate some of your valuable insight. I have a 78 GS 1000 that has an 82 GS 1100EZ motor in it. It is basically stock, save for a Stage 1 Dynojet kit, V&H header and 1166 Wiseco kit. I have about 3500 miles on the top end rebuild, and the bike has been very reliable. It had about 40k miles at the time of the rebuild, and I opted not to split the cases. About two weeks ago, oil started sprinkling out of the ignition cover, more so when accelerating hard through 7-8000rpm. I replaced the crankshaft end seal, but same result. There is no visible scoring on the crank or case, but.....I did notice when I started the bike to check the replacement seal for leaks that the crank end was shaking quite visibly. Increase rpm and it would smooth out. Didn't think much of it at the time until this. Has anyone experienced this? Do I need crank bearings? I don't have horrible or strange noises, but this problem has definitely surfaced within the past few hundred miles. I don't experience much vibration, save for a bit of "chug" at idle after coming off my freeway commute. I've never really been able to tune that out. Thanks for any wisdom, I fear this is not GOOD NEWS...

[rapidray]

Call me at 714-356-7845 so I can talk to you about it. Ray.

[bwringer]

.....I did notice when I started the bike to check the replacement seal for leaks that the crank end was shaking quite visibly...

That is indeed Not Good, if I'm correctly picturing what you're describing.

Call Ray -- he's seen the innards of more of these things than anyone.

And report back here what you find out.

[J Paster]

Thanks. I'll call this evening. It sounds like my 550 restoration's going on hold. Crap.

[kamesama980]

usually expelling oil out seals at high rpm and/or throttle means too much blowby: it's pressurizing the crankcase and blowing the oil out the seals. they aren't meant for much pressure.

[J Paster]

usually expelling oil out seals at high rpm and/or throttle means too much blowby: it's pressurizing the crankcase and blowing the oil out the seals. they aren't meant for much pressure.

I tried my commute without accelerating past 3-4k rpm today, and it still leaked the same. So, I gave erroneous info about the high rpm leaking. I did talk to Ray about this, and am currently making a jig in order to check the crank end with a dial indicator. He also noted that the previous seal as well as the one I installed (monkey see, monkey do) is backwards! I'm hoping for a pretty true crank, then the wait for another seal, then report back here with good news...

[J Paster]

Ok, my thanks to Ray for the expert diagnosis. Max variance on the crank ends were .003. I can now see that I was getting a little freaked out watching the rotor for my dyna ignition moving around. Looking at that seal I can understand now that it is backwards. Spring shouldn't face out. Ray says they show it backwards in the manual. Gold side should face out, not rubber side. Another seal is on order. How embarrassing! Thanks guys, this site is awesome!

[rapidray]

Glad I was able to help! Ray.

[bwringer]

*sniff* I just love a happy ending...

Don't feel too bad -- I installed the crank seal backwards when I built the engine in my GS850 two years ago. Don't know why. I knew better...

However, mine lasted about 20,000 miles before it started leaking, and went another 5,000 before it got embarrassing.