I know it's probably been asked a few times, but what is a good synthetic oil to put in your primary. I'm thinking of putting Mobil 1 V-Twin 20W-50 in the engine, I'm just not sure about the primary. I've heard some rumours of synthetic oils causing clutches to slip, any truth to this. Anyone have any suggetions?

 

I used Mobil 1 synthetic but switched to a regular motor oil, 30w and the clutch seems to have a better feel. Many say you are just wasting money using a syn in the primary, especially for the clutch. Some have said they felt slipping with a syn. Harley has a primary oil they recommend, not a syn.

 

Harley recommends their syn3 for the primary as well as their other holes. I run regular dino for the primary and mobil 1 for then engine and trans.

 

I am switching from Syn3 to Redline MTL in the primary. Also going to switch to Redline Shockproof Heavy in the Trans. Will let you know if any different.

 

Personally..........I didnt like the feel of the clutch when I tried synthetic in the primary. I switched back to HD Formula + and like it much better.

 

I put Redline MTL in the primary &amp\\; Redline Heavy Shockproof in the tranny at the beginning of the summer. Clutch feel is great, runs quiet, &amp\\; clunk noise when shifting was reeduced.&nbsp\\;
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FYI - can get the Redline products here:
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http://www.racerpartswholesale.com/category/Oils_And_Brake_Fluid

 

I have used Mobil 1 20/50 for V-Twins in the engine and primary and Mobile 1 75/90 in the tranny with no noticable ill effects. But it does run cooler and shift smoother.

 

I've heard those rumors also.&nbsp\\; Haven't read of any good reason to switch from Formula+ for primary.&nbsp\\; Others holes, yes.&nbsp\\; Primary NO.

 

They did when it first came out. They dont anymore.

 

I have synthetics in all three holes. Been that way for me since 500 miles on the odometer.&nbsp\\;Now, over 13,000 miles and no issues or complaints.
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Previously- AMSOil in all three holes, now (last two oil changes), Mobil-1 V-Twin in engine &amp\\; primary, a stronger Mobil-1 for the tranny.
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BTW: My dealer is still pushing Syn3 for all three holes. (but my bike has never been to the dealer's service department).