“Early” Harley-Davidson Fork Oil Specifications


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As some of you may know from following me on Facebook, Twitter, or Instagram, I am neck deep in a front-end rebuild of my 1972 Harley-Davidson Shovelhead FLH.  I have completely disassembled both fork legs, methodically cleaned each internal part, and ordered the replacement parts necessary to put things back together.

harley-davidson fork oil specifications

Of course, when all is said and done, I am going to have to refill the front forks.  Therefore, I thought I would share with everyone some Harley-Davidson fork oil specifications – in particular, information regarding the proper fork oil weight to use and capacities for major models.

Weight:  As a default, use 20wt.  You will want to consider 10wt and 30wt under more extreme conditions (riding-wise or temperature-wise).

Capacity by Model:

-Note that “wet” means you drained the fork leg from the drain plug and plan to refill, while dry means the fork leg has been completely disassembled for a rebuild.  In the first case, there is a little residual oil left in the fork leg.  In the second case, you are filling a fork leg that is bone dry (requiring a little more).

-Most Harley-Davidson models have a drain screw in the bottom.  However, the only way to truly drain all the oil is to remove the leg from the triple tree and turn it upside down.

-If needed, but the conversion between ounces and mL is 1 oz = 29.5735 mL

-The quantities given are per fork slider.  You will need to order twice the quantity listed in the table below to fill both fork legs.

-The table generally covers “earlier” model Harleys, as these are the ones I am more familiar with.  If you have another Harley or even another make/model of motorcycle and need your specification, please feel free to reach out via the contact page.  I have a ridiculous number of manuals, and I will try my best to help where I can.

Sportster (up to 1972)5.56.5
Sportster (1972 – 1983)5.06.0
Sportster (1984 – 1987)5.56.5
FL/FLH (1948 – Early 1977)6.57.0
FL/FLH (Late 1977 – 1984)7.758.5
FX/FXE (1972)5.56.5
FX/FXE (1973 – 1983)5.06.0
FXR/FXRS (1985 – 1986)6.07.0
FXWG/FXST (1980 – 1984)9.010.2
FXWG/FXST (1985 – 1998)10.211.2

Okay folks, that’s it – my post on Harley-Davidson Fork Oil Specifications.

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1 thought on ““Early” Harley-Davidson Fork Oil Specifications”

  1. I own a 1977 FL I’m not sure if it’s early or late is there a way to tell and dose heavyweight oil make the forks stiffer?

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