Chasing an oil leak - What is this?

[JustDennis]

On the 2004 Big Dog Chopper I just got, there is an oil leak when sitting. Looked under the bike and seems to be coming down the motor. Looks to be coming from one of the two screws below. I don't know enough about these S&S engines. What are these two and do they look right? The top one looks backed out??? Sorry for the bad picture - these are on the rear, bottom of the engine behind the oil pump. Thought maybe just need tightening but afraid to mess with them too much since I don't know what they are.

Any information or help appreciated. I hate oil leaks. Just trying to get the bike sorted. It's in great shape but a couple of small things to sort.

 

[Mickmorris]

On the 2004 Big Dog Chopper I just got, there is an oil leak when sitting. Looked under the bike and seems to be coming down the motor. Looks to be coming from one of the two screws below. I don't know enough about these S&S engines. What are these two and do they look right? The top one looks backed out??? Sorry for the bad picture - these are on the rear, bottom of the engine behind the oil pump. Thought maybe just need tightening but afraid to mess with them too much since I don't know what they are.

Any information or help appreciated. I hate oil leaks. Just trying to get the bike sorted. It's in great shape but a couple of small things to sort.
View attachment 100053

That one that looks partially backed out is where you would have a crankcase breather. Looks like the P.O. removed it. If you can determine that’s where the oil is coming from you probably just need to tighten it up. You can see my breather line going to that opening where you have the one backing out.

 

[JustDennis]

Thanks. I’ll tighten and see what happens.


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[john sachs]

On the 2004 Big Dog Chopper I just got, there is an oil leak when sitting. Looked under the bike and seems to be coming down the motor. Looks to be coming from one of the two screws below. I don't know enough about these S&S engines. What are these two and do they look right? The top one looks backed out??? Sorry for the bad picture - these are on the rear, bottom of the engine behind the oil pump. Thought maybe just need tightening but afraid to mess with them too much since I don't know what they are.

Any information or help appreciated. I hate oil leaks. Just trying to get the bike sorted. It's in great shape but a couple of small things to sort.
View attachment 100053

If 1 is at 90 degrees, and the other is at 45 degrees, they are for the case/engine breathers. If your engine is venting through the heads, then usually those 2 case breathers are blocked off with pipe plugs. A better picture would help, to be certain.
John

 

[JustDennis]

Thanks for the help. Figured out it was the bottom plug. Removed and put some Teflon on it and think it fixed it. Now I’m wondering why. Someone must have changed to top venting versus crankcase?


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[Mickmorris]

So yeah you are venting through the heads/ carb. Lots of people plug the crankcase but my understanding is that is better to have both. John will probably disagree because if my memory serves me well the last time I seen him he told me that I should remove it. And if anyone knows S&S it’s John.

 

[john sachs]

So yeah you are venting through the heads/ carb. Lots of people plug the crankcase but my understanding is that is better to have both. John will probably disagree because if my memory serves me well the last time I seen him he told me that I should remove it. And if anyone knows S&S it’s John.

I like breathing through both the heads, and case. If you do this, you need to block off the vacuum line to the front head.
John

 

[JustDennis]

I like breathing through both the heads, and case. If you do this, you need to block off the vacuum line to the front head.
John

Vent thru either of the crankcase fittings? Also a pic of line in head to block would help. Thanks again


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[john sachs]

Pick the plug, at the back of the case you want to remove, and replace it with a hose barb and a piece of hose. You should have a small hose barb and fitting going to your intake manifold, from the front head. Remove the piece of small hose, and block off the fittings on the manifold and front head.
John