I use Mobil 1 15W-50 in the motor, Mobil 10w-40 in the primary, which I may try a Mobil 1 10w-30 next time, which would give a bit more friction to the clutch. And in the transmission I use the Mobil 1 75/90 gear oil. Just my 2 cent.

 

i had 68K on my 01 RK using 15W50 Mobil 1 since the first change. the difference in additives is not worth the extra cost for V-Twin. compare an additive at 860 ppm in 15W50 vs 1020 ppm in V-twin (examples not actuals) difference is miniscule.

 

G2156 - A Study of Motorcycle Oils

A fairly easy to read study - don't know who wrote it, but it substantiates another study that directed me to Mobil 1 "V-Twin" in the first place. One of the factors especially in a air cooled v-twin is the amount of Zinc (ZDP) the oil contains. Mobil 1 V-Twin rated high for this element.
I also ran it in my Primary and tranny for 1 go around, but found my clutch slipping (slightly) and trans didn't shift well after a few miles.
I currently run HD formula + in the primary, and Mobil 1 75/90 syn gear lube in the trans and I think I've finally got her dialed in.
I also tried B&M Trick shift ATF Syn in the primary for a couple thousand. Initially it was great, clutch worked perfect and stuck now. But within a thousand miles it started grabbing and getting noisy. That's why I went back to HD Formula +.
Everythings good now!

 

well do as you want. I choose to use V. twin because all the data I've read shows it has higher levels of zinc and other friction reducing additives (HEAT) then cage oils. I'll spend a little extra every 5K. I plan on keeping this ride for long time.

 

Are you using synthetic 15/50 and 10/40?

 

Yes Mobil 1 is synthetic, all three oils including the 75/90 gear oil. Lots of guys have been using the 15w-50 for 10's of thousands of miles and have been happy. It becomes a question of what you are comfortable with for yourself.

 

I should have known Mobil 1 was syn. Well I am due for a 20k mile service and was heading to Orielley's to pick up the V twin Mobil one. So Wal-mart here I come for the inexpensive Mobil 1 Hog Yild fluid change.
Later,

 

77Tulsa,

My two cent again, I didn't like the 15w-50 in the primary, I didn't think the clutch grabbed as well. I am happy with the 10w-40. But I want to experiment with the 10w-30 next change. I may end up back at the 10w-40.
The 75/95 in the transmission, I feel is just better suited to the types of loading and wear that a transmission gear system sees vs. a formulated motor oil. Again my choices.

 

I am going to try the 10w-30 in the primary. The extra 20/50 will go in the riding lawn motor. I am looking for an increase of low end torque and off the line hole shot on the dixon ztr.

 

I know my Craftsman push mower seems to like the used Mobil 1 from my bike oil changes............. Oh and it runs cooler...........

If you are going to try the 10w-30, let me know what you think. I won't be getting to this till around December.