What exactly is in HD Primary oil ?

[wedge]

Any non synthetic 20-50 is fine according to E1. I use Valvoline Dino 20-50

[rokytnji]

If you have no choice. No oil is worse than what ever is on the shelf.
Easy enough to drain it later on when you find what you want.
Only uses a quart.

like posted above. I use Pennzoil 20/50 when in a pinch.
Even straight dino 40 ,30 wt is better than empty.
When on a trip.

[Fifty150]

https://youtu.be/nxoQ-Yd3zw0?t=1027

I use Mercon V. It's already in my garage.

[hexnut]

I use Red Line 75W90 GL5 gear oil in my hot rod Sportster. Been using it for over 20,000 miles with no issues. Does not harm yellow metals. Its equal to 50 weight motor oil.

From red Line

Thank you for contacting Red Line Oil, in the shared Sportster primary/transmission the 75W90 is recommended, a product that has been used extensively and performs well.

The 75W90 is the product we have have used for a number of years with very good results in Sportster/Buell transmissions, matching the viscosity and type fluid called for.
The 80W Motorcycle Gear Oil is a lower viscosity than called for, the ShockProof gear oils can due to their unique characteristics could cause sticking of the Harley clutches.
The 75W90 would be preferred and recommended over 80W Motorcycle Gear Oil in these applications.

There can be issues with some GL-5 gear oils in certain applications. Some can be corrosive to brass, bronze or copper, not an issue with our GL-5 gear oils, they don’t cause corrosion, pitting or metal removal. In a synchro equipped transmission the friction modifiers contained in many gear oils can make them too slippery, though not the case in a motorcycle transmission with dog rings.


So if you want the right viscosity and dont want to worry about it damaging anything, go with Redline http://www.redlineoil.com/product.aspx?pid=133&pcid=4

[John Harper]

I used M1 75W90 for a while, and switched to Belray STL later on. No real reason, both work well, just long time user of Belray products. As infrequently as I need to change it here in San Diego, a few bucks more isn't really a big deal, especially considering it's only a quart. I kind of like the fact it's red, rather than just motor oil color, were an unlikely leak develop.

John

[hexnut]

Mobil 1 75W90 gear oil works really well. The only gear oils Im aware of that are a problem are..

UNSAFE GL-5 Oils
Royal Purple MaxGear 75W-90 GL5......... 4A Trans Black
Mopar Syn LS additive..75W-90 GL5....... 4A Trans Black
Lucas 75/90 Synthetic75W-90 GL5......... 4B Graphite Blk

[Tomcatt]

Originally Posted by hexnut

I use Red Line 75W90 GL5 gear oil in my hot rod Sportster. Been using it for over 20,000 miles with no issues. Does not harm yellow metals.

+1 on Redlines' GL5 gear oils. I went thru (tried) a bunch of different wt/type gear oils and ATF's in my Sportster. Stuff I had on the shelf. I'm running Redline 75w140 GL5 as the transmission shifts best with it. The clutch still wants some Red Line 80301 Limited Slip Friction Modifier added to help the no grenade plate chatter/squeal.

[brucstoudt]

^^ wouldn't the friction modifier risk clutch plate slippage?

[Tomcatt]

Originally Posted by brucstoudt

^^ wouldn't the friction modifier risk clutch plate slippage?

In theory, yes. I've got a Barnett kevlar plate set, an E-1 +15% spring and no trace of it slipping with the friction modifier added. It helps with but doesn't eliminate the chatter/squeal it sometimes does.

What I should do is get the XR/Buell narrow plate pieces.

[Bluto]

Mobil 1 V twin is OK too and it is synthetic, have used it for the primary/gearbox without issue.