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New to me 1990 FXSTC with 11K miles. I always change the fluids in a vehicle when I purchase it. The engine oil level was fine before servicing as was the trans (easy enough to check those two). I didn't pull the derby cover initially to check the primary level.

I drained the oil and got about 2.5 quarts out - give or take. I drained the trans and got about 21 ounces out - give or take. Seems about right. I drained the primary and damn near over flowed the small pan that I use for changing the primary fluid. I bet I had over two quarts in the primary. The derby cover seal was doing it's job and wasn't leaking. From my experience, there is no way to intentionally get that much primary fluid into the primary UNLESS you laid the bike on it's side. So what am I looking at here - probably a crank shaft seal that is allowing the engine oil to fill the primary?

Thoughts?

 

I wouldn't panic (yet). A bad crank seal will suck the primary fluid into the engine. 1990 was first year they eliminated the steel main bearing spigot so the only way for oil to migrate into the primary is if the screws for the rotor output retainer are missing. It's possible someone serviced it like an older model and filled it to the bottom of the clutch cover, rather than to the bottom of the clutch spring. Just refill properly, ride all you can and "call us in the morning."

 

Congrats on your very new Evo. I would go ahead and add the correct level to the primary and ride it. Keep an eye on your oil level.

Now as to the cause. It could be as simple as the PO overfilled the primary. It is more than likely your crank case seal. You can also get oil migrating from engine into the primary through the two small screws holding the plastic piece keeping your stator wire in place. For now, I just ride it and monitor the fluid levels. Because of the low miles on the bike, I would not be worried about the steel case insert coming loose. That's the worse case scenario, but just don't think that's your case.

 

Thanks guys - no panic here. Nature of older vehicles, I guess. I figured I might encounter so "issues" on this low mileage bike, sometime more miles is better than a low mileage bike that sits.

I have done just that - drained all fluilds and replaced with proper amount. Once I get everything else sorted so I can ride it, I will monitor oil level and check primary level as well.

I am thinking of ultimately doing an open primary, this may just accelerate that decision if I have to pull things apart to replace the seal. Plus I need a new primary cover as this one is "sweaty" (pitting, etc) so rather than spend that money on a new chrome primary, the open primary is calling my name!

 

If you do go open primary remember, the seal installs spring in. It's spring out for wet primary.
I think '90 was the year they eliminated the cast-in steel insert. Maybe '90 1/2. Someone correct me if I'm mistaken...

 

Don't forget the possibility that PO simply put too much fluid in the primary.
Not everyone that works on their own bikes should hold tools.

 

Amen to that!

 

Sorry- but not true. My 92 had exactly the same senario. Too much fluid in the primary. The motor PUSHES oil into the primary. Its a very well known issue. Change the crank seal-(buy 2-they are cheap). I didnt remove the inner primary or the stator- just put 2 small wood screws in the old seal- pop it out- tap in new one.
I did it 3 years ago no problems since.

 

May i ask for the sake of education (as well as my memory), did your's have the steel bearing spigot or is it all machine aluminum at the bearing?

 

Im not really sure what you mean by a spigot- i think it means a tap of a sort- but my 92 had the motor push oil into the primary - as well as a 99 crate motor did the same thing. Primary fills up- motor oil level goes down. Change the crank seal-my problem was solved. Is it the OP's problem too? Not sure- just offering my experience with the issue.