A good while ago I bought new primary and inspection covers, but never got around to installing them until just recently. You can imagine the words I used when I cracked open the primary drain plug to let the old oil drain out, and was greeted by an off-white/tan, slightly foamy milkshake. Taking off the cover confirmed it was water, as there was condensation all over the inside of the cover. This was my first time changing the primary oil on my 2015 883 that I bought used in 2020. I was a bit early changing the primary fluid, as the bike only has about 8.5k miles. I don't make a habit of driving in the rain, and I've only had to one time. I don't believe the clutch is slipping or anything, before or after changing the fluid. I replaced the milkshake with Royal Purple 85W-140 gear oil, and I'm thinking I'll have to change the fluid again. The new primary cover I installed has a window in it, and I can see that there's still some milkshake lingering in there.

 

I'm much more concerned that you're bathing your clutch in gear oil than I am the moisture in the oil.

 

That is not how it works. Read your manuals. If you are not doing the mileage then you change the oil based on anniversary (annually) instead.

 

Do you take a lot of short rides or start the bike and let it idle to charge the battery?
Doing either of those will cause condensation inside the motor.
Ride the bike for a while. Run it at least 20-30 miles to get the motor up to operating temp so you basically boil the condensate out of the oil.

 

So for all you know the primary oil was not changed since 2015 if the previous owner did not follow maintenance. Did you change all the fluids when you purchased it?

1. Not only is it your primary oil, it is also your transmission oil.
2. Read your owner's manual and use the proper fluid recommended.
3. As above, make sure you get the bike up to operating temperature for at least 30 minutes to burn off any moisture.
4. What does your engine oil look like?
5. Probably time to do a brake fluid flush also.

 

Moisture in the oil is the issue, gear lube on the clutch is not going to hurt a thing.

It`s a Sportster, the clutch and transmission are both lubricated by the same oil.

 

You don't ride your bike long enough to heat up the oil to expel moisture. Always ride at least 30 minutes when you ride. Don't fire up your bike for a minute or two over the winter, you just make things worse. Always get your engine up to full temperature whenever you start it. Your engine oil could look the same for the same reasons.

John

 

Even in a big twin, gear oil is not required in the transmission and results in more heat. But at least there, there isn't a concern the additives are no good for it.

Gear oil does NOT belong in a wet clutch.

That said, I have found it in there and the owners weren't complaining of any issues. But it's NOT the correct fluid for the task.

 

Whatever companies want to call the stuff they state on the bottle it's good for wet clutches as well as gearboxes.

 

How is your bike stored? Outside has a greater chance of condensation.
How often and how long are your rides? Short rides will not burn-off condensation.
Are you someone that likes to turn the bike on just to hear the motor but does not ride it.....That will not allow bike to heat-up and burn-off the condensation.
Did you check any fluids at purchase or any time during ownership? Perhaps it already had condensation.
Did the gaskets look good? Perhaps there was water getting in.

From a distance it reads like bike:
Maintenance was not being monitored.
Needs to go for a few long rides (100 mile) and then fluids/filters changed.
Do not go by mileage in your case since manual will suggest yearly change for low mileage bikes.
I would review air filter and spark plugs too.

Regarding fluid selection...that is a whole other topic.