Hey, I was wondering if it is possible to change the sprocket shaft bearing seal (the seal on the crankshaft behind the stator) while the engine is still assembled? I have a mysterious primary fluid leak where I'm loosing primary fluid but can see no leaks anywhere on or under the bike. The bike is parked on a tile floor in my living room so if so much as a drop came out, I would see it on the floor.

I have the entire inner primary off while replacing tranny bearings and have pulled the stator. It looks like I might be able to grab it and get it out (while mangling it), but the last thing I want to do is trash the seal and not be able to get the old one out. I also don't have the bearing installation tool.

The old seal looks brand new; in fact it was replaced when the previous owner had the motor rebuilt by HD in 2005 and has only about 6K miles on it.

 

If that seal was shot you would more likely end up with the primary filling up with engine oil due to the pressure differentials.

 

Are you overfilling the primary and its ending up in the tranny?

 

There are only three possible things that could happen.

1. The oil is hitting the ground
2. the oil is going in the motor
3. the oil is going in the trans.

1 is the most likely...if 2 or 3 is happening, they will be over filled and easy to troubleshoot. And yes with the proper tools you can change the seal...try to do it without the proper tools and you will cost yourself a lot of money. And if the oil is moving somewhere else ...it is more than likely a venting issue.

 

If the stator had ever been pulled and the installer didn't use loctite on the 4 little screws that hold it on, the motor could be sucking the primary oil into the crankcase that way.

I've seen 2 that did that.

 

Thanks for all your replies. I've been told that oil will migrate from the tranny to the primary rather than the other way just because there's more pressure in the tranny than in the primary. I don't really see how oil could go one way or the other since there's a big open area when the drive sprocket is. I would think that in either case the oil would hit the ground rather than migrate to the opposite case.

I really don't think the oil is hitting the ground since everything is very clean and as I said, I have no drips on the white tile floor where the bike is parked.

I have been told that oil can get sucked from the primary into the engine by the scavenger system in the motor through the sprocket shaft seal which is why I was looking at it. But like I said, this seal looks brand new.

I hadn't heard about the stator bolt holes leaking through to the engine but when I pulled off the stator, I was looking there and thinking of that as a possibility. The bolt holes don't appear to be drilled all the way through though. There is red locktite on the torx screws. The manual doesn't say anything about applying locktite, but it does say the screws are not reusable and must be replaced.

Unfortunately, the last oil change I did when I found out I had an issue about 500 miles ago, I wound up filling the engine oil tank too full. Therefore, I couldn't see if I was getting extra oil in the engine. It's possible it was blowing through the breather into the carb.

Since I don't have the installation tool, I'm going to leave it for now. It's not too difficult to tear the primary chain back off to access that seal if I still have an issue. Before that, I'll get the installation tool.

Is there a tool to remove the seal? The book doesn't say a word about taking it off. It also doesn't say a thing about the primary seal on the main trans shaft. All it mentions and shows is the starter jackshaft seal. This is the HD manual and this one isn't as good as some of the Clymers I've seen and that is hard to believe.

 

Pulling the crank seal is not hard. I have done it two ways. One is to drill small holes on each side. Put two small sheet metal screws in and pull it out. Also you can LIGHTLY tap in the edges until you can get a grip. MAKE SURE you do not burr up the sleeve that sits over the crank shaft or it will keep leaking. Also do all this with the stator mounted on the motor. It will help support the lip on the engine case that the stator slides over and the seal presses into. You obviously don't want this to break.

One more thing the tiny screw holes where that little plastic stator plug clamp mounts do go all the way into the motor. **** poor deign on HD's part. I finally got mine to stop leaking and they leaked on my last evo.

 

The seal on the sprocket shaft is easy. Screw a small self tapping screw into it and pull it out. the bearing set behind it is two matched bearings, the only one you have access to without splitting the cases is the outer. It is pressed on the shaft so your not going to be disturbing anything. as far as an installation tool, a piece of pvc pipe works great. The only thing you can possibly do is get it crooked or seat it to far. Hope this helps.

 

Thanks for the additional comments Dan and 06. That's what I was thinking of doing but drilling without knowing how much clearance is behind the seal is a little disconcerting.

Bingo!! I thoroughly checked the stator mounting screw holes and they bottom out 1" in. The plug clamp holes are different. They go back at least 1.5" for screws that stick into the hole less than .25". And on top of it, one of the screws was not screwed in at all, it was just hanging there by the silicone that was mean to seal the stator plug to the primary case. I think that would probably be my issue. Gonna fill the back of those holes with silicone.

 

They are a major pain for sure for such a tiny part. Silicone will certainly slow it down and hopefully stop it. I had to take other measures with mine due to the dry set up. Plus I hate the idea of those screws coming out and getting into my stator/rotor. The shop manual calls for blue loctite on them but in my opinion they are way to small to even grip enough.

I managed to get them to stop leaking on my older EVO chopper with red permatex high temp. And that motor was BRAND NEW! The oil was coming out pretty good.