1998 stock Fatboy, I've owned it for 6 years and have always used Mobil1 20w50 Synthetic in the primary. Saw "Lucas Primary Chaincase Oil" in the local auto parts store and wondering if I should switch. Are there any pros/cons to running one over the other?
Any input from the EVO gurus?

 

Are you having any troubles as things are?

 

As long as it's compatible with the clutch...I've always used HD primary fluid till i went to a belt drive..

 

I tried the lucas 20w50 syn in my V rod an it didn't like it as well as mobile or AMS. Did harley stop making the primary fluid?

 

No problems, just always on the look out for something that may work even better!
Plus, I'm cheap and the primary oil is $5 cheaper!! :-)

 

I use ATF.
Can't get much cheaper and it works fine.

 

There is your answer. As was previously stated "as long as it's clutch compatible", and it obviously is.

 

I use synthetic ATF. I don't think it's cheaper, but it sure makes the clutch work smooth. I was using Mobil1 ATF, but the local auto parts store didn't have it last time I changed a primary oil (chopper), so I went with the Royal Purple ATF.

HD doesn't have the primary chain case oil like they used to. What they sell now doesn't work for me. Makes gear changes all clunky.

 

I tried ATF and Valvoline Motorcycle 10w40 Dino and like that best and it's cheap. $6 a quart or so. It's made for wet clutches no friction junk. I

 

I ran type F ATF for quite a while in both my old Heritage and in the EG. It did just fine, never an issue. Now I run the HD primary and transmission oil. Never noticed that it mattered. Next change will be back to ATF.