I have an early 1986 1100 Sporty with an interesting problem. Between oil changes, the transmission fluid slowly finds its way into the engine and by the time the bike is ready for an oil change, the engine sump is on the verge of overflowing and the transmission fluid level is very low.

Has anyone ran into a problem like this?


Oh, I'm new to this forum. I have been a Harley rider/enthusiast since the early 1980s and spent a lot of time in the saddle. The 1100 has always been my favorite bike and has never let me down. The bike has been sitting for a few years --- things happen. I finally have time to look at the problem.

 

How many miles are on it? Maybe it needs a new gasket somewhere.

 

The only culprit I can think of is the crankshaft oil seal, on the primary side. Fluctuating pressure in the crankcases could draw oil into the engine.

 

Thinking along those lines ... maybe a clogged vent line on the trans/primary.

 

The bike has around 40k miles on it, but the problem started not too long after I bought it. LOL! That was 30 years ago! We were thinking it was a flaw in the engine casting so I put off further investigation and just put up with the fact that every oil change included a transmission fluid top off. I think it was because -- well, you spend a lot of money on a new bike, I think it cost around $5600 back then, you have a 3 year loan to pay off, the bike was just off warranty, and the last thing you want to know is that the engine is bad. With that in mind, I kept it close to home except for a few trips to Sturgis and Colorado.

The thing is is that the draining of the transmission has always been consistent. The vent line has never been clogged. I would be delighted if the crankshaft oil seal has been the problem all this time. Maybe it's time to crack it open and check it out.

The trouble is is my heart really isn't in riding anymore after a friend of mine had a close encounter with a deer last summer. He was dressed for the slide, but still spent a month in the hospital and has a lot of medical expenses ahead.

Anyway, it might be a bit before I get to it. I'll post the results.

 

I had this in my road King. Very slight tear in seal acted like a check valve and pulled oil from gear case to primary.