Title says it all. I've tried heavy and light oil and it doesn't make any difference.

The top of the tranny has a U-tube which I assume is for venting but that's where all my oil comes pouring out of.

It doesn't happen at low speed but when I'm touring constant at about 65-75 it will start blowing out slowly. It emptied itself after around 2500 miles of constant 65-75mph touring.

I was told I'm getting pressure from elsewhere.. but I don't know where to start.

I'm sure it's the tranny oil not mixed with other oils because mine is red and when it drips while at a gas station, it's always the same shade of red as what's in my tranny.

 

Make sure the vent tube is not kinked or plugged.

The only way you could be getting excess pressure would be a bad engine crankshaft seal, but that would cause the primary to be overfilled with engine oil.

 

Make sure to check the level with the bike vertical and make sure the vent isnt restricted. I also re-routed my vent tube, up under the seat. The little "J" tube was just too short and tended to collect water on my bike.. No more leaks for me..

 

Up under the seat sounds like a long way to go. I was thinking of making an 'S' shaped tube so hopefully the oil will stay in.

Checked and there are no kinks. No idea about the crankshaft seal but my primary only holds primary fluid. No leaking of engine oil.

 

I used to work on cars, I dont call 1ft a long way..

Seriously, I bought an S&S fuel line from my indi. It had a 90* bend in the end of it and I got to thinking that it would be a natural fit for the trans, so I got another.. Simple fix for me..

 

My 94 FXSTC has been doing the same thing, mostly in colder ambient temps it seems. For now I've re-routed that J hose up under the left/lower oil bag mount and wire tied it there with the end pointing down.
It's a little higher that way and does not seem to let the oil out but I'd still like to know what causes it to spritz oil. It just started doing it, I didn't overfill the tranny or change it, nothing different.

Seems to me if there was enough of a leak from the crank case to cause that much preasure them I'd be showing a big loss in engine oil as well.

Anyone know why some bikes do this?

Doug

 

I wish I could remember where I read it, but I've seen this problem mentioned before. I wish I could remember what I had for lunch too, but that's another story. I want to say there was a fix that involved a real simple cross drilling of the area in or around the the cover near where the vent tube goes. It was really simple, and you had to remove the top cover to do this naturally. Maybe that will jog someones memory, maybe even mine.

Like another person said, the only way to explain part of this would be if the crankshaft seal was blow and it was pressurizing the primary chaincase, and eventually the transmission through the clearance around the input shaft. Even at that, the oil would have rise a bit to reach the vent. So I'm guessing it's getting slung up there through the normal motion of the gears. It's almost like some deflector thing is missing.

 

my '92 fxstc does it a little when cold out. I have a 10" tube that goes up and then curves down on the inside of the primary case.

 

It souds like it is overfilled to me.....

 

Did you ever see the display they used to put in auto stores, the one with the crank handle? the faster you cranked the more the oil would climb in the gears and higher it would go over the common stuff?. If you haven't over filled the trans, that might be whats happening. What kind/ weight oil you running?.,,