Mobil 1 Oil
Account Retired
Joined: Oct 2009
Posts: 3,245
Likes: 12
From: Here
I would listen to people like iClick and Dawg. They have done the research and know what they are talking about. I took their advice and put ATF in my primary. I could tell a big difference right away how the clutch responded. I would use a good gear oil in the tranny.Three top choices would be Redline Shockproof Heavy, Mobil1 75W90 or 75W140, Amsoil severe Gear. I think if you choose any of these, you can rest assured you have the best lubrication. The reason I chose the oil I use in my bike. I can buy it at my local Advance Store down the street. Mobil 1 20W50 V-twin 9.50 a quart.... Good luck and ride safe.
Cruiser
Joined: Feb 2010
Posts: 147
Likes: 0
From: Johns Creek, GA
My local repair shop says that you absolutely should not try to run the engine oil in all 3 holes. He's got 35 years working on Harleys and I believe him. He said there was something out on this a few years back, sorry but I can't remember if it was a TSB or something like that that discussed the reasons why it shouldn't be done. Many have said they run it in all 3 but I wouldn't do it if it was free oil.
Grand HDF Member
Joined: Mar 2007
Posts: 4,923
Likes: 266
From: Deep in the heart of New Jersey
I would only run an oil in the trans if the bottle said it was designed to be used in the trans. Amsoil has a gl-1 rating and mobil1 v-twin says it can be used in the trans. It doesn't say it's ok to use it for trans use on the mobil 15/50 wt oil bottle tho. Regular gear oil can be used, but its the same weight as 40-50 wt motor oil with additives to help it not shear. Its cheap, but the synthetic version is pricey, and when I tried it I could smell it on hot days so I drained it out and ran Amsoil 20/50. Shiftwise I couldn't tell any difference.,,
Grand HDF Member
Joined: Sep 2007
Posts: 4,122
Likes: 44
From: Boise Idaho
Use any oil you want as long as it has a CF rating on the bottle, if not spend the extra buck or 2 to get it.
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Grand HDF Member
Joined: Sep 2009
Posts: 3,808
Likes: 285
From: Green Country Oklahoma
-Mobil 1 15/50 in winter months ok
-Mobil 1 v twin in summer because it has air cooled motor cooling agents in it
-Any motor oil in primary as long as not too thick
-Redline shock proof in tranny IMO is best
This works for my bike no problems
-Mobil 1 v twin in summer because it has air cooled motor cooling agents in it
-Any motor oil in primary as long as not too thick
-Redline shock proof in tranny IMO is best
This works for my bike no problems
Seasoned HDF Member
Joined: Mar 2009
Posts: 24,736
Likes: 9,246
From: Snow Hill, NC
15w50 $22 for 5 quarts at walmart....advance auto is running a special this month fo rthe v-twin 20w50 for 7.99 a quart...do th math.. iwould use primary fluid in the primaryh and gear oil (75w9o0 or 75w140) in the tranny...I use 15w50 in the crank...