Date: 29-03-24  Time: 06:10 am

Author Topic: fork oil / air gap ??  (Read 1192 times)

74eldiablo

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fork oil / air gap ??
« on: 20 March 2019, 10:08:21 am »
Ive just put some 15w oil in my 2001 forks with pre load adjusters.
465ml measured out correctly.


Pumped the forks to release air bubbles.
After 10 minutes each leg sitting i measured the air gap


It was way off the specified 132mm (at least 15 > 20mm off)
Should i add more oil to make the air gap the correct height or just leave the measured out 465ml

Thanks
« Last Edit: 20 March 2019, 10:09:41 am by 74eldiablo »

bandit

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Re: fork oil / air gap ??
« Reply #1 on: 20 March 2019, 02:56:33 pm »
With the inner fork compressed without the spring fitted,I personally with add more oil to the 132 mm level.  Smile

robbo

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Re: fork oil / air gap ??
« Reply #2 on: 20 March 2019, 03:16:12 pm »
Had this problem a year or so back on a thou. If I remember correctly the correct amount of oil meant the gap was far too small, meaning fluid would have to be removed. Spoke to a mech at a Yam dealer and he said ignore the airgap and stick with the prescribed volume.
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darrsi

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Re: fork oil / air gap ??
« Reply #3 on: 20 March 2019, 06:19:17 pm »
I had similar when i last did my oil.
Forks were empty, and the levels were measured out spot on, but the air gaps were different as well.
I made the air gaps the same and have never had any problem with handling at all.
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daviee

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Re: fork oil / air gap ??
« Reply #4 on: 20 March 2019, 06:46:16 pm »
bad advice to ignore the air gap if its different from leg to leg then the spring pressure will be different as the air gap compresses with the movement of the forks so it will affect how the forks operate who ever told you otherwise is clue less and not a mechanic

74eldiablo

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Re: fork oil / air gap ??
« Reply #5 on: 20 March 2019, 07:29:11 pm »
I already made the airgaps upto 132mm by adding extra oil, i just wanted to see what other people had experienced whilst doing this job.
So my intial gut feeling was correct as confirmed by most of you guys.


Thanks for your input.


Now im off to spray the top yoke ready to fit the new bars

His Dudeness

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Re: fork oil / air gap ??
« Reply #6 on: 20 March 2019, 07:59:23 pm »
I add the recommended volume then add or remove a small amount to get the air gap equal in both forks and at the recommended height. I think this guy does suspension setup for track bikes. He talks about air gap in this video