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WERK I WERK I is offline
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Join Date: Jan 2003
Location: Wisconsin
Posts: 3,302
Originally Posted by Ronnie's.930 View Post
Dave - understood.

I have never seen proof that there are additives specific to wet clutches in any oil on the market. This subject has come up many times on message boards and at the track and no one has ever supplied any proof to back-up this myth (at least that I am aware of). Not to mention, these additives, if they exist, would not harm the bearings of non-wet clutch machines since wet-clutch engines use the same bearings and such as any other moder(ish), four stroke, dry clutch engine
Here's an excerpt from Dennis Bachelder of the American Pertroleum Institute....
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"Higher performance engine oils such as API SJ thru SM will contain some level of friction modifier. While the friction modifier improves fuel economy, it is not compatible with wet clutches used on motorcycles. The friction modifier causes the wet clutch to slip. This is especially true if the motorcycle manufacturer recommends using only engine oils carrying API SF or SG Service Categories.
API recommends following the Original Equipment Manufacturer's (OEMs) oil recommendations. Typically an API SJ through SM engine oil would include some friction modifier. Only if the [motorcycle's] OEM indicates that higher performance engine oils such as API SJ, API SL and API SM it is possible to use these engine oils in these motorcycles."

Dennis L. Bachelder
American Petroleum Institute
1220 L Street NW
Washington DC 20005 USA
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M1 V-Twin is a API SJ class motor oil.
I apologize my previous logic was completely a**-backwards. The wet-clutch systems would be incompatible with SJ oils since there are friction modifiers/additives (low-friction inducing ingredients). In any event there are inherent differences between most motorcycle and automotive motor oils. Can we put the "myth" to bed now?
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 06-21-2013, 03:57 PM
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