I use and like Harleys 99851-05 FORMULA+ Transmission and Primary Chaincase Lubricant. I have been putting it in my Evo since I bought it. Since I am useing it, I am kinda wondering what weight it is???

It doesn't say on the bottle. Kinda funny. Is it a 20-50 or a straight weight? Not that it matters all that much, but I was just wondering.

Neil

 

I saw an analysis on it once and it's a straight 50W mineral oil.

 

If you are talking primary......us folks run about anything in there. The HD products, motor oils and even automatic transmission fluid and everybody that runs what they put in there swear by it. A good motor oil is likely fine for the primary as long as it doesn't have any particular additive that could cause clutch slippage. I developed a severe leak one time and was losing a quart every couple-hundred miles. I started putting in the very cheapest thing I could find that was oily at gas stops until around 1200 miles on down the road when I finally found a dealer that could replace the gasket for me.

I know this is more information than you asked, but I thought you may be thinking about using another product.

 

Oh, I get that there's a 100 choices for what to drop in the primary. And 100 threads a 100 pages long fighting about it. I just chose the HD stuff for the primary because I like it. That being said, whats it weight? Lost1 thinks it may be straight 50. I have no idea. I would have guessed 20-50. So I figured I'd shoot the question out.

 

Well....I see you have also wasted countless hours looking at these oil related threads and watching people fight over their favorite product. Fun...ain't it!

Lost1 may be right, but I bet it's a 50W gear oil rating and not a 50W motor oil rating. 50W oil would seem too light for the transmission, but I know lots of folks run the syn3 in there.

I guess you know by now that my simple answer is....I haven't a clue. Maybe somebody will chime in with your answer. There is nothing wrong with being curious.

 

Here's a VOA (virgin oil sample) for Formula+ as tested by Amsoil I found on BITOG:

Harley Davidson FORMULA+ Trans and Primary Chaincase VOA
(Mini VOA via Amsoil)
Petroleum based.
Ca 169
P 230
B 210
S - some
Zn - essentially none
No other elemental additives.
Vis. within SAE 50 range.
Listed as a GL-1, does test out as a GL-3.




And here's H-D's published specs:

Harley Davidson Formula+
Application: recommended for heavy-duty service in manual transmissions where the manufacturer normally recommends either engine oils or GL-1 lubricants.
Specific Gravity: 0.857
Pounds per Gallon: 7.14
Viscosity, ASTM D 445,
cSt at 40°C: 168.04
cSt at 100°C: 20.10
Viscosity Index, ASTM D 2270: 139
Brookfield Viscosity, ASTM D 2983,
cP at -26°C - 28,800
cP at -40°C - n/m
Pour Point, ASTM D 97, °F (°C): -60 (-51)
Flash Point, ASTM D 92, °F (°C): 507 (264)

 

i have run the harley primary oil, 10w30 car motor oil, 10w40 car motor oil and automatic transmission fluid. they all work the same as far as i'm concerned. my stock original primary shoe has a few scratches on it. about 90k on it.1985 flhtc.

 

Well, I just dump a straight quart of the stuff in my primary every time I change the oil. Always comes out sparkling clean and the clutch works great. Harley recommends the stuff, so thats why I use it in the primary. To be honest, I use it in the tranny as well, but I modify it to my specs. I cut the bottle in half and add 4 ounces mobil1 75W-90 gear lube and 4 ounces Lucas stabilizer for the tranny. Thats my secret formula and the tranny works like the bomb. But as far as the primary. I just dump it in. I'm guessing from all ya'alls replies that it is in fact straight 50 weight without any friction modifiers. Does that sound about right? Again, I'm really just wondering out loud, I'm probably gonna stick with it no matter what.

 

Yes, it is a simple SAE50 GL-1 conventional oil (made by Citgo). The only additives that it contains are Calcium, Phosphorus, Boron, and trace amounts of Sulfer and Zinc.

 

Judging by the limited add pack of Formula+, and relatively long OCI (10k miles) spec'd by Harley, I'd say Wesson oil, in the proper measure, would suffice in the primary, lol.

While I use Shockproof Heavy in the tranny, my primary seems happiest with Formula+, so that's what it gets. I've tried the $10-$15/qt boutique oils, but good ol' F+ gives me the best clutch engagement, so I'll stick to that...