Is there any way the trans oil can leak into the primary chain case?
When I pulled the derby cover the primary fluid had a slight gear oil smell to it.
I am using Schaeffers primary oil in the primary and 75w-90 gear lube in the trans.
I seen a small leak coming from the back side of the primary case from the area by the pulley but it seems to have quit now.
It seems the IPB inner race is walking in my 2007 fxdb.

 

Not normally, the front sprocket is in the space between the tranny case and the inner primary but, the tranny mainshaft is hollow and there is a pushrod to activate the clutch. If fluid is getting from the tranny to the primary, it would need to go through the center of the mainshaft. I would think your tranny is seriously overfilled if that is happening.


An overfilled tranny will leak out the mainshaft seal behind the pulley....

 

This is only an opinion, I once walked the bearing on a 5 spd mainshaft and final drive gear. The final drive gear had the outboard needle bearing slid thru the gear and against the bearing on the other end. I believe the root cause was a scissored flywheel assembly. Basically the compensator was running 60 thou out loosening and tightening the primary chain pulling and releasing the clutch hub, puling on the mainshaft and all bearings in the line.


Check your runout on the front sprocket or at the least pull the inspection cover and rotate the assembly to confirm the difference between loose and tight on the primary chain. If the worst happens you will go from very loose to very tight and tight could be walking the bearing.

 

I just put in cams a couple of weeks ago and I measured the crank runout then. It was only .003 and I was pretty happy about it. When I had the leak behind the primary case by the pulley it did not smell like gear oil. It also leaked on the primary side of the sprocket, not the trans side.
I'm pretty sure the trans is not overfilled but I could check again...after it warms up. It is around 0 degrees for the next few days.

 

Sounds good - As for the inner primary seal, that is a common failure and is more of a nuisance leak as a properly filled primary will not have enough fluid to reach the bottom of the seal and when on the jiffy stand it is lower at the seal. All you get is splash that works out. Maybe a 2 Hr fix to remove and replace that seal, stator o-ring, cover gasket. And if you nick the seal putting the inner primary back on it will weep oil.

Maybe you just have some debris built up around he seal lip allowing it to wick out.... Can you get it on a lift and wash between the front sprocket and the inner primary seal with a solvent?

 

You can keep a check of the level of your tranny fluid to see if it is low. But typically the tranny fluid does not make it's way into the primary.

Odds are that engine oil isn't getting into the primary either from the case seal. You'd note the primary as being overfull and the engine being excessively low on oil.

The inner primary seal often leaks when the race shifts on the input shaft. It's best to replace the race and the bearing along with the seal to stop that leak. Baker offers a 1 piece bearing and a heavy duty seal that's a good upgrade. Other than that the quad seal between the input / output shaft can give you a leak behind the inner primary. This is often due to a bit of warp in the tranny mainshaft.

I'll bet that smell you are smelling coming from the primary means your stator is going bad. The first sign of the stator burning out is more of a smell like an electric transformer burning up in the primary oil.

If it's not showing an irregular charge voltage, if you have a gauge, then get out the test meter and run a full diagnostics test on the charging system, starting with stator output and shorting to ground issues. Here's a guide. Even though this is in the EVO section the charging system is pretty much the same on all HDs.

Be sure to let us know what you find out.

 

Yeah, the primary is not leaking now. I was just giving background info. No bearing noise or weird vibrations.
I was more concerned with the smell. I will check out the electrical system and see if the stator is failing.
Thanks for the suggestions all.
I'll report back when I find something out.

 

Also check the vent on the trans and make sure it's not plugged, if the vent is plugged the transmission will pressurize and force fluid out where ever it can, including down the mainshaft.

 

I will put that on my list of things to check. Thanks.

 

Ok, it got slightly above freezing so I went out and checked a few things.

Trans is not overfilled and the vent is not plugged.

The primary oil smells like a really weak version of the 75w/90 gear oil in the trans. It doesn't seem to smell like a burnt transformer (yet) and I have smelled a few burnt transformers.
I sniffed a new sealed bottle of Schaeffers primary oil that I have and it does not smell like gear oil.

So I grabbed my Fluke 87 meter and pulled the stator connector apart.
The stator shows open to ground using the 40M ohm range.
Zero'ed (using the rel button) and using the 4 1/2 digit display it shows .05, .07, .13 ohms between the three legs using the lowest ohm range. The .05 and .07 does seem kinda low.
The AC output was 27 - 38 volts on all 3 legs depending on RPM. All 3 are the same at same RPM.
The full charging system shows 14.5 to 15 volts when running.

I'm still confused.
Should I tear it apart and look for a problem or should I wait until it warms up and ride it until I can get a better indicator of what is wrong?