Mobile 1 15w-50 in primary?

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Jun 17, 2009 | 11:38 AM

sunnenman

Thread Starter

Cruiser

Joined: Jul 2007

Posts: 165

Likes: 4

From: Oakley, MI

Mobile 1 15w-50 in primary?

Greetings,
Due to traffic, I am posting this here for the experts. I recently picked up an 08 SG at a great price. It only had 780 miles on it. I just changed out all the fluids at 1000 miles. I put redline in the tranny. Mobil 1 15W-50 in the engine and primary. Is the 15W-50 going to be ok in the primary? I read something about moly in this oil and didn't know if it will cause any problems. Thanks
-sunnenman

Jun 17, 2009 | 11:48 AM

VTwin-Goodies

Former Sponsor

Joined: Nov 2007

Posts: 47,839

Likes: 1,956

From: SoCal

I run that in the primary or 20w-50 v twin and I have had no problem with either one. You should be fine. Of course with oil everyone has their own opinion.

Jun 17, 2009 | 12:14 PM

skooba

Cruiser

Joined: Jan 2007

Posts: 163

Likes: 1

From:

I use the Mobil-1 syn automatic transmission fluid. There are friction reducers in oil which you don't want in your clutch. 15-50 does have as many as the light viscosities but you don't need any in a wet clutch. Some say it doesn't matter, maybe it doesn't but I have not had a single clutch burp, smooth a silk and neutrel is now a perfect click in every time since I started using it.

Jun 17, 2009 | 12:15 PM

n8dc

Stellar HDF Member

Joined: Mar 2007

Posts: 2,034

Likes: 45

From: Michigan

My last change the Indy told me to run 10w40 amsoil in the primary and of course 20w50 in the engine and the amsoil gear lube in the tranny. Ive recently switched to mobil 1 v twin oil in the engine but next time im gonna do the 15w50 in the engine and then decide what to run in the primary..

Last edited by n8dc; Jun 17, 2009 at 12:54 PM.

Jun 17, 2009 | 12:43 PM

Heath

Former Sponsor

Joined: May 2008

Posts: 303

Likes: 1

From: Mason City, Iowa

You can get some clutch slippage if you're using an oil with friction modifiers in it. The oils made for gassers will tend to have this in them. Most diesel oils and motocycle oils don't. The diesel oil won't say this on the bottle, but the motorcycle oils will.

Jun 17, 2009 | 01:03 PM

soos

Grand HDF Member

Joined: Sep 2005

Posts: 4,890

Likes: 73

From: MA

Running a synthetic in the primary is a waste of money. The oil used in the primary is more for cooling than lubrication. A good 10w40 is more than adequate. I use Castrol GTX.

Jun 17, 2009 | 01:11 PM

pappashelby

Tourer

Joined: Mar 2007

Posts: 330

Likes: 18

From: Sacramento area

Thats what I've used for many miles. Buy the 5 qt bottle at Walmart, 4 for the eng and the other primary. Its overkill but handy.

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Jun 17, 2009 | 01:17 PM

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by skooba

I personally don't think we need high-tech oil in the primary, and I use a common fossil 20w50 which works very well. All you need is something to cool the cluch disks and lube the chain, which doesn't take much. A friend who's an engine builder uses ATF Type F with success.

The use of some additives like moly is good for the engine but has no place as a coolant for clutch disks. That said, I've never heard of an HD owner who's had a problem with using a high-grade synthetic in the primary, except possibly one. Someone in a recent thread here mentioned clutch slippage after swapping cams (to 255's), and he was using Amsoil 20w50. He was going to try a more mundane oil and report back but if he did I never saw his response. There was no indication that the oil was the culprit, but I have the same engine/cam setup and have no clutch slippage.