Did you even bother to read my above post? I'm telling you, I had this SAME issue and it turned out my crank seal bit the dust... it was put in backwards anyways. Even though engine pressure is greater than primary pressure, the primary oil was still getting sucked into the motor. The only reason I noticed is I happened to pop my dipstick to check my oil level as I noticed I was getting some sumping out of the breathers. It was up to the top full of type F ATF. Pull the friggen dipstick and check dude...

The only other way it could be happening is there is a little plate that holds your stator wires down, and it's held down by 2 screws. These can leak if they're not tight and do the very same thing. Ball is in your court... most of these guys in here are worried about "sikk front ends" and other stupid **** and have never been inside their bike... I've been inside mine hundreds of times. Been there done that... up to you to figure it out now.

 

Like this way. Which is designed to keep primary out of engine? Go figure. Probably since on the engine side, the oil is just runoff.

 

I'm not an engineer... I'm a dumb ASME code welder. I've asked everyone, even my wife who doesn't know anything about this type of stuff, and they all agreed that the lip seal is supposed to point in the direction of pressure, AKA towards the motor. I don't understand why people put them in backwards... idiot logic.

 

The OEM dual lip garter spring faces the primary (cup out) on the crankshaft sleeve and also toward inside. (when you pull alternator rotor off, you can see one garter spring and makes it appear the wrong way) It is a little confusing till you look at seal (least OEM one)..not sure what an aftermarket one may look like. The smaller one for the starter jack shaft faces the inner bearing that supports the jack shaft. It appears opposite of the crank seal. (it's purpose is to keep oil from getting out toward starter) the engine on a TC free breathes thru the one way rubber poppet rubber valves in the head into the air box. However, the air flow is relatively slow since only atmospheric pressure is pushing air in (unlike the exhaust which is forced out) and little oil gets into throttle body. The primary breathes thru the clutch pushrod tube and shares transmission vent. The oil bag on Softail, Dyna and Cruisers is also vented thru a passageway to transmission and shares it's vent. If you look at mine in the above post, it looks wrong since you can see the lip and garter spring but it is correct.

 

Things must be different on a TC in that respect then. On an EVO the lip should face inward, although there is debate on which way it should face, stock is inward. A TC doesn't use umbrella valves for the breathers? Otherwise it sounds like they breath mostly the same through the heads.

 

I've had this concern myself. Here's what I did. I drained my primary for the very first time on a bike that was new to me....it looked like there wasn't enough drained fluid.

I measured it....only a 1/3rd of what it should've been! I thought to myself "QUICK,PANIC!" I started a thread on hd forums and got the usual smart Alec remarks and doomsday scenarios from all the arm chair mechanics. Just like web md, all the symptoms pointed to cancer.

I filled it up per spec, rode it for two weeks and repeated above process....as much came out as went in.....PHEW! Repeated again, this time rode for a month, all good. As it turns out, I suspect the previous owner had not filled it to spec.

Sometimes the most obvious answer is the right one.

 

Yep!!