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As some of you may know from following me, 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.
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.
Harley Davidson Fork Oil Information
Weight: As a default, use 20wt. You will want to consider 10wt and 30wt under more extreme conditions (riding-wise or temperature-wise).
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, the conversion between ounces and mL is 1 oz = 29.5735 mL
The quantities of fork oil given are per fork slider. You will need to order twice the quantity listed in the table below to fill both fork legs.
Harley Fork Oil Quantities by Model
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.
| Name/Model | Wet | Dry |
|---|---|---|
| Sportster (up to 1972) | 5.5 | 6.5 |
| Sportster (1972 – 1983) | 5.0 | 6.0 |
| Sportster (1984 – 1987) | 5.5 | 6.5 |
| FL/FLH (1948 – Early 1977) | 6.5 | 7.0 |
| FL/FLH (Late 1977 – 1984) | 7.75 | 8.5 |
| FX/FXE (1972) | 5.5 | 6.5 |
| FX/FXE (1973 – 1983) | 5.0 | 6.0 |
| FXR/FXRS (1985 – 1986) | 6.0 | 7.0 |
| FXWG/FXST (1980 – 1984) | 9.0 | 10.2 |
| FXWG/FXST (1985 – 1998) | 10.2 | 11.2 |
Okay folks, that’s it – my post on Harley-Davidson Fork Oil Specifications.
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?