Does Anyone Know ?
Ultimate HDF Member
Joined: Sep 2005
Posts: 8,641
Likes: 26
From: Ozark Country
A "Virgin Oil Analysis" (fresh unused oil) has shown that HD Formula Plus is basically a 50w dino oil with a very limited additive package. Nothing at all special about it..
Each to their own, but I don't use, and won't use it in any of my bikes.
For some reason Harley won't publish the viscosity or detail information on most of their oil's, and I prefer to use a product in which I have more information about the additive package used, etc....
As far as the viscosity (thickness), 50 weight "motor oil" has the same viscosity as 90 weight "gear oil"..
The below chart will give you a better idea of the viscosity comparison between motor oil and gear oil. As you can see, a 75W90 gear oil has approximately the same viscosity as a 20W50 motor oil.
Each to their own, but I don't use, and won't use it in any of my bikes.
For some reason Harley won't publish the viscosity or detail information on most of their oil's, and I prefer to use a product in which I have more information about the additive package used, etc....
As far as the viscosity (thickness), 50 weight "motor oil" has the same viscosity as 90 weight "gear oil"..
The below chart will give you a better idea of the viscosity comparison between motor oil and gear oil. As you can see, a 75W90 gear oil has approximately the same viscosity as a 20W50 motor oil.
Road Master
Joined: Jan 2008
Posts: 772
Likes: 4
From: ohio
I'm pretty sure a lot of the guys on here run Syn 75w-90 gear oil in the gear boxes without problems. I remember cHarley saying thats what he runs (Mobil1?) I'm gonna switch mine out here probably at the next change.
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
The Magnuson-Moss Warranty Act may is quite helpful here. Under this federal law, you can sue on breach of express and implied warranties. The main point of interest here is that the Act says warranty coverage may not be conditioned upon the use of only the vehicle manufacturer's parts unless the parts are provided free of charge. In other words, use of a non-carmaker product should not void your warranty unless it caused the problem.
Basically, you can use any oil you want as long as it meets the manufacturer's specs. And Mobil 1 15w-50 car oil, 75w-90 Gear oil or 20w-50 bike oil exceeds HD's specs. Tell your dealer to back up what he's saying by putting it in writing. Tell him if he says you can only use the HD oil, he has to provide it free under federal law. He'll backtrack. If he gives you any grief, find another dealer, and report him to the local BBB, or even to your state attorney general. __________________
credit to: pococj
Ultimate HDF Member
Joined: Sep 2005
Posts: 8,641
Likes: 26
From: Ozark Country
Most of the guys I know with Sportsters (including a couple of HD dealership mechanics) run Mobil 1 75W90 Gear Lube in the combination primary/tranny. As you can tell from the above chart, 75W90 Gear Lube has about the same viscosity as 20W50 Motor Oil, and the Mobil 1 Gear Lube also carries a API GL-5 rating.
Some of these Sportsters have pretty high mileage (one of them with over 90,000 miles), and no body has experienced any type of problem with the tranny, clutch pack, etc..
Other synthetic users are running Amsoil or Mobil 1 20W50, but just about any synthetic that isn't "Energy Conserving" and contains a very limited Molybdemun rating can be used. Even low cost Mobil 1 15W50 that many use in their engines should be fine as it contains less than 90ppm of moly, which is less than that of many 'motorcycle specific' synthetic oils.
And there are also any number of good 'conventional oils' that would work just fine, including low cost Rotella T 15W40 that is JASO-MA rated (contains no moly) and also carries the API CJ-4, CJ-4 Plus, CH-4, CG-4, CF-4, SM, SL, and SJ ratings.
But anyway, use whatever you want and I'll stick with the Mobil 1 75W90 as I prefer to use a good GL rated gear lube instead of motor oil in manual transmissions.
Some of these Sportsters have pretty high mileage (one of them with over 90,000 miles), and no body has experienced any type of problem with the tranny, clutch pack, etc..
Other synthetic users are running Amsoil or Mobil 1 20W50, but just about any synthetic that isn't "Energy Conserving" and contains a very limited Molybdemun rating can be used. Even low cost Mobil 1 15W50 that many use in their engines should be fine as it contains less than 90ppm of moly, which is less than that of many 'motorcycle specific' synthetic oils.
And there are also any number of good 'conventional oils' that would work just fine, including low cost Rotella T 15W40 that is JASO-MA rated (contains no moly) and also carries the API CJ-4, CJ-4 Plus, CH-4, CG-4, CF-4, SM, SL, and SJ ratings.
But anyway, use whatever you want and I'll stick with the Mobil 1 75W90 as I prefer to use a good GL rated gear lube instead of motor oil in manual transmissions.
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