HD Syn3 Recommendation
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Joined: Apr 2013
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From: CC TX
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Been riding Harleys for decades - a long time; been riding motorcycles for over a half century.
With exception of synthetic engine oil in some piston engine aircraft I have never seen an engine fail because of having the "wrong" oil in it. This experience includes cars, trucks, heavy equipment, offshore fishing boats, aircraft, race cars as well as lawn mowers, chain saws and ...
Back to Harleys.
For the engine, generally I've run many flavors but mostly avoided Syn3, unless it was a free service or something where I didn't have a choice. Mobil 1, Rotella-T, Twin-V just about any 15-50 or 20-50 oil rated for turbocharged diesel engines. Lots and LOTS of Harley miles using these oils (even Royal Purple for a while) with nary an oil related issue at all.
Transmissions would get a quality synthetic 85-90, 85-140 or similar. Remember, gear oil has the viscosity rated numerically different than engine oil. I have not, do not and would not run Syn3 in the transmission.
Primary case seems simple as many think "it's only a chain" and that chain and sprockets arrangement is used on countless transfer cases of 4X4s that run just ATF - forever. However, it is important to remember that those T-cases do not contain a clutch pack. For that reason, I have used H-D Formula+, ATF Type F or other quality ATF fluids - nary and issue.
If you read the Owner's manual, you will see specifications for lubricants - stick with those of your preferred brand but the recommendation of Harley-Davidson branded lubricants is, IMHO, the MoCo's opinion on what brand will make them the most money.
With exception of synthetic engine oil in some piston engine aircraft I have never seen an engine fail because of having the "wrong" oil in it. This experience includes cars, trucks, heavy equipment, offshore fishing boats, aircraft, race cars as well as lawn mowers, chain saws and ...
Back to Harleys.
For the engine, generally I've run many flavors but mostly avoided Syn3, unless it was a free service or something where I didn't have a choice. Mobil 1, Rotella-T, Twin-V just about any 15-50 or 20-50 oil rated for turbocharged diesel engines. Lots and LOTS of Harley miles using these oils (even Royal Purple for a while) with nary an oil related issue at all.
Transmissions would get a quality synthetic 85-90, 85-140 or similar. Remember, gear oil has the viscosity rated numerically different than engine oil. I have not, do not and would not run Syn3 in the transmission.
Primary case seems simple as many think "it's only a chain" and that chain and sprockets arrangement is used on countless transfer cases of 4X4s that run just ATF - forever. However, it is important to remember that those T-cases do not contain a clutch pack. For that reason, I have used H-D Formula+, ATF Type F or other quality ATF fluids - nary and issue.
If you read the Owner's manual, you will see specifications for lubricants - stick with those of your preferred brand but the recommendation of Harley-Davidson branded lubricants is, IMHO, the MoCo's opinion on what brand will make them the most money.
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Joined: May 2008
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From: South Carolina
If you read the owner's manual, you will only see HD specs for lubricants, no API or JASO spec (like the rest of the automotive and motorcycle world uses).
Last edited by Dan89FLSTC; Dec 26, 2022 at 05:12 PM.
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From: Las Vegas
Funny isn't it? I've never met an engine that gave 2 ***** what brand of oil is used. They all like the proper viscosity, but after that nothing else really matters.
Seasoned HDF Member
Joined: May 2008
Posts: 21,176
Likes: 12,753
From: South Carolina
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