Fork oil amount issue

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Dec 11, 2022 | 01:10 PM

Keimier

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From: Il

Fork oil amount issue

I recently had a fork tube unscrew itself (pinch bolt was broken) and lost fork oil. I purchased new dry forks (new ones have chrome lowers) and the harley service manual states to add 12.9 US oz with a dimension of 4.72 in (119.9 mm). I added the 12.9 oz and the measurement ends up being 6.875 in (174.6 mm). I measured the old fork that didn't blow out and got around 5.9 in (150mm). I know the old fork is going to have a little fluid loss due to age and removing the spring which has oil on it.

If I add the 12.9oz, I fall short on the dimension. If I go by the 4.72in, I'm "overfilling" according to the manual. My question is what should I go with? The 12.9oz or the 4.72in? I don't want to hydro-lock with too much.

Bike is a 2005 Heritage Softail Classic FI with 48,591 miles on it with 41mm forks (and from what I can tell, the fork oil has probably never been changed).

Dec 11, 2022 | 01:16 PM

Juan L

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From: Ft. Worth, TX

Buy one of these and do it by height, not quantity.

Dec 11, 2022 | 01:41 PM

Keimier

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From: Il

I have a tool like that. But my problem is I'm going to have to add 2-3 ounces more fork oil that Harley recommends. Would this be okay?

Dec 11, 2022 | 02:25 PM

Juan L

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From: Ft. Worth, TX

Make sure the level is at 119.9 mm and go with that. It is the correct method to set fork oil height.

Last edited by Juan L; Dec 11, 2022 at 02:26 PM.

Dec 11, 2022 | 04:49 PM

Keimier

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From: Il

I went with the height of 119.9. Now I gotta put the bike back together and see if it works.

Dec 13, 2022 | 09:59 AM

Juan L

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From: Ft. Worth, TX

Any reports?

Dec 16, 2022 | 01:21 PM

Keimier

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From: Il

Just got the bike back together yesterday. Too cold to ride, but I went out and did a few start/stops and it feel stiffer that the old ones which makes sense cause the old oil was low and the viscosity was damn near water like.