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.
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.
| 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. Please like on Facebook, tweet on Twitter, or +1 on Google+.
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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?