Help with front fork springs
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Road Master
Joined: Aug 2007
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From: Northern California
Help with front fork springs
My Works Performance spring kit arrived, so I had a go at this project. I started with the Right Hand fork, and removed the old spacer/washer/spring. I then used a grease/oil pump to try to suck out all of the old fork oil. I noticed that there was not that much oil in there and it was very dirty. The Left Hand side had a lot of oil and it was very full.
I then used the service manual's value of 787ml of fork oil. After the bike was put back together I rode it and the forks do not compress very much at all. A friend thinks I hydraulic locked them. It is not clear from the manual if H-D means 787 for both fork tubes or for each fork tube. Another thing, I had a devil of time pressing down on the fork cap nuts, as when the PVC spacer was covered up, it would force oil to come out of the tube and make a mess. It was a good thing I covered the bike up with an old sleeping bag and a lot of towels.
I then used the service manual's value of 787ml of fork oil. After the bike was put back together I rode it and the forks do not compress very much at all. A friend thinks I hydraulic locked them. It is not clear from the manual if H-D means 787 for both fork tubes or for each fork tube. Another thing, I had a devil of time pressing down on the fork cap nuts, as when the PVC spacer was covered up, it would force oil to come out of the tube and make a mess. It was a good thing I covered the bike up with an old sleeping bag and a lot of towels.
Cruiser
Joined: Jun 2010
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The figure in the manual is probably for filling a 'dry' fork....one which has been taken apart and has all the oil out of it. A 'wet' fill is best done by filling to a specific level, measured from the top lip of the fork stanchion. I don't have that figure.
Banned
Joined: Oct 2007
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I see you did not take my advise. You can not suck out all of the oil, you have to invert the fork tube and pump it many times and let it drain to get it all out. You have to set the oil level with the fork tube vertical and compressed with out the fork spring installed. With the forks on the bike you can't properly measure the height because it is at an angle. You can get it approximate if you measure the high point and the low point find the difference and divide it in half then subtract the difference from the high point to find the level, but the fork still has to be compressed which is a pain in the *** to lower the bike enough to fully compress the fork tubes. You can go by the recommended amount of oil, but you have to get it all out in order to do it that way. Pull the wheel and take the fork tubes off the bike, start over and do it right or you will never get the level correct, especially now.
CB
CB
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Road Master
Joined: Aug 2007
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From: Northern California
I see you did not take my advise. You can not suck out all of the oil, you have to invert the fork tube and pump it many times and let it drain to get it all out. You have to set the oil level with the fork tube vertical and compressed with out the fork spring installed. With the forks on the bike you can't properly measure the height because it is at an angle. You can get it approximate if you measure the high point and the low point find the difference and divide it in half then subtract the difference from the high point to find the level, but the fork still has to be compressed which is a pain in the *** to lower the bike enough to fully compress the fork tubes. You can go by the recommended amount of oil, but you have to get it all out in order to do it that way. Pull the wheel and take the fork tubes off the bike, start over and do it right or you will never get the level correct, especially now.
CB
CB
Thanks for responding. I don't understand why one has to go through all of that. I don't understand why the forks have to come off the bike, which I am not willing to do. I don't understand why the fork have to be compressed. That makes absolutely no sense to me. Furthermore, I don't understand why every last drop of old oil has to be removed. There has to be a spec for how much oil is required with the bike on a jack, with the forks extended. Sure, I did not remove every last drop of 'old' oil, but fork oil is perfectly 'happy' with brand new oil being added to some old oil. So, given that why can't one figure out how much oil should be seen in the tube with the new fork springs in. Yeah, there will be a different level with the tube on the bike, which will be at an angle - but there will be a number for the front and the back, and two are related by a trigometic function, so given one number we will know the other number.
Banned
Joined: Oct 2007
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Thanks for responding. I don't understand why one has to go through all of that. I don't understand why the forks have to come off the bike, which I am not willing to do. I don't understand why the fork have to be compressed. That makes absolutely no sense to me. Furthermore, I don't understand why every last drop of old oil has to be removed. There has to be a spec for how much oil is required with the bike on a jack, with the forks extended. Sure, I did not remove every last drop of 'old' oil, but fork oil is perfectly 'happy' with brand new oil being added to some old oil. So, given that why can't one figure out how much oil should be seen in the tube with the new fork springs in. Yeah, there will be a different level with the tube on the bike, which will be at an angle - but there will be a number for the front and the back, and two are related by a trigometic function, so given one number we will know the other number.
No, you did not even have to replace the oil in the first place and No you do not have to replace all the fluid. But wrap your head around this, all the **** fluid is in the bottom of the fork. Yes there is a spec for the oil, but how much oil is still in the fork????? Lets see, 26.9 oz - what is left in the fork = Who Frigging Knows. Since you don't know, you are going to need to use the oil height spec, to guesstimate the proper height since you don't want to collapse the forks and they are at an angle, I guess you are going to have to get out your slide rule.
Hope you get it figured out.
CB
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Road Master
Joined: Aug 2007
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From: Northern California
I talked to my street glide and road glide buddies, and they have a drain plug on their forks. Their H-D service then gives a 'wet' oil capacity and a 'dry' oil capacity. hmmm. ok, so, to do this "right" on a Dyna, I need a HD fork holder, tool p/n HD-41177. Only catch is Harley won't sell the thing to the public.
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