Amsoil 20/50 v-twin for primary/engine oil & severe 75/95 in tranny is what I use I think it's best or just 20/50 v-twin in all three holes.

 

Any good 20W50 in the motor. Any good *GEAR* lube in the transmission. Any good dino 20W50 in the primary. I like Castrol products so I use Castrol synthetic in the motor, & Castrol dino 20W50 in the primary 'cause it's cheap. I use Redline Shockproof in the transmission 'cause you don't change it often.

 

This is not a "cheap" bike, and it is your bike!
You will get hundreds of hundreds different answers from people telling you what they are using.
For example: Your bike is mine, I will drain all the oil, and replace with motorcycle oil. I use Mobile 1 V-twin for engine, and primary, and Mobile 1 75W-90 for transmission. They are relatively expensive, but the bike runs cool, and especially I feel good.
I have ordered through Amazon, and they are on sale!
There are no tested data about car oil for motorcycle, and there is also no data say car oil is bad for motorcycle, so that is an unknown. I will go with what I believe is good for my bike: Motorcycle oil.
Good luck!

 

On the contrary, Mobile 1 website said 15W50 Synthetic was good to run in air cooled v-twin engine's. Been several writeup's about it on here and other forums.
It is as good as the Mobile 1 v-twin for these harley engines. Lot's of forum member's run it. Advance Auto run's a sale on Mobile 1 oil real often. Heck...even in Amsoil's test, mobile 1 is usually second in most of the test they run. Probably first, they just don't admit it...LOL

 

Curiously, I went to Mobil! web site, and read about 15W-50 http://www.mobiloil.com/USA-English/..._1_15W-50.aspx but, there is no where said that this oil is for motorcycle.
Where have you seen the info on Mobil1 web site?
Just want to know!
Nick

 

v twinn just means safe for clutch since most "other"brands dont have a seperate primary.car oil can lead to clutch slippage,but is just fine (or better)in the motor.in the gearbox i use gearlube.

 

I didn't say it was for Motorcycles. There was an article on Mobil's website sometime back where guy's wrote in and ask if mobile 1 15W50 car oil was ok to run in their Harley v-twin engine's. The reply was, yes it was OK! There's been several threads on this forum where member's posted the finding. I'm sure iclick was one member who posted a response to it. I wouldn't be running it in my RK and my wife's SG Trike if it wasn't just as good as Mobil 1 V-twin, maybe better!!!!
Use whatever makes you feel warm and fuzzy!!!

 

This is a true statement. Using any oil that you put in the primary that has an energy conserving label on the bottle, has friction modifiers in it, and without a doubt, will cause clutch problems. As far as engine and transmission. Gear lube in the transmission, and as far as engine oil, you get enough opions here, take your pick.
Jonnierock

 

try this link:

http://www.mobiloil.com/USA-English/...Davidsons.aspx

 

Here is a good read: http://www.mobiloil.com/USA-English/...AQs.aspx#FAQs2
My bad! I misunderstood your post.
But then, they are somehow conflicted with their comparability between car and motorcycle. Read the above link.
One thing I have learned from Mobile1 web site that the bike can run at higher temp if you are using motorcycle oil, and it has much more anti-wear additive (phosphorous). I know the mobile1 answer is car oil can be used, but it somehow sounds like they are in the weak side.
I'll stick with the motorcycle oil, so I can run cooler, and less wear. I'd like my bike last longer. Once upon the times, I have used Rotella (Shell oil) in motorcycle, and it's all changed after I put in the mobile1.
Thanks much for the link.