Author Topic: Fork seal replacement ineffective  (Read 435 times)

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Offline Rambo

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Fork seal replacement ineffective
« on: May 22, 2018, 11:51:50 pm »
So, replaced the fork seals and now the ride seems pretty sallow. On a scale of one to ten, ten being fully extended, the sitting ride height sits firmly at two, and offers very little dampening. I can watch the forks extend freely so I know that's not the problem What gives? I went with 15w for the fluid, and 7 psi for the air. The spring already has a 2.5" spacer in each tube. I had my old man, who has had three concours, with me for the whole thing, and I'm a decent mechanic myself. I'm 5'11 228lbs, so I can't imagine it's a weight issue.

Thrall me with your acumen, folks.

Offline Bob_C_CT

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Re: Fork seal replacement ineffective
« Reply #1 on: May 23, 2018, 07:38:27 am »
What year is your bike? I see you set air pressure, so it must be an older vintage. The fork oil height is set differently depending on the year of your bike. At what level did you set the oil height? Springs in or out? forks extended or compressed?
I think your oil level is off, Pre 1994 models, oil level measured with springs out, forks fully extended. I can't recall the correct level of oil but someone with an older C10 should chime in shortly.

BTW, others have capped off the air system (got rid of) with good results and never looked back.
« Last Edit: May 23, 2018, 07:58:14 am by Bob_C_CT »
97 C10,ZRX Front, Meanstreak rim

Offline m in sc

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Re: Fork seal replacement ineffective
« Reply #2 on: May 23, 2018, 06:44:51 pm »
I like my forks a bit stiffer,. so im almost a full oz over stock volume after setting the oil height to factory specs. (im also lighter than you) maybe your springs are worn out? but id venture to say you're low on oil.


Online MAN OF BLUES

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Re: Fork seal replacement ineffective
« Reply #3 on: May 23, 2018, 07:06:30 pm »
So, replaced the fork seals and now the ride seems pretty sallow. On a scale of one to ten, ten being fully extended, the sitting ride height sits firmly at two, and offers very little dampening. I can watch the forks extend freely so I know that's not the problem What gives? I went with 15w for the fluid, and 7 psi for the air. The spring already has a 2.5" spacer in each tube. I had my old man, who has had three concours, with me for the whole thing, and I'm a decent mechanic myself. I'm 5'11 228lbs, so I can't imagine it's a weight issue.

Thrall me with your acumen, folks.

The title of your thread, conflicts with what you are experiencing... the actual "seals" play no part in "normal" fork ride height, other than if they are pre '94 like yours is, they don't seal the air in... so, if they don't hold the 7 psi, you will experience a reduction of resistance to compression...
Normal ( pre '94) spring "free length" should be 514mm,(20.24") with a minimum of 504mm, (19.84") I suggest replacing those springs with the Progressive Springs, that Murph's Kits sells... for the cost, they will help out tremendously... and then you can do away with the additional air requirments also... and iirc, the 2-1/2" piece of tube up top, is not used with the replacement, as the springs are longer.
I replaced the springs on both my C10's with those, and found it offered up what I needed, to reduce the "sag height" on the front, and did not cost a lot of money... a frugal cost of $75

https://www.murphskits.com/product_info.php?cPath=1_97&products_id=52&osCsid=5DTddyIBV37PnOiTliojo3


Oil level plays no part in the "height" of the forks, it only comes into play during the dampening and rebound action of the forks...
But nonetheless, it should be measured and be at the correct level, iregardless...

I'll also caution, that the oil level is a "distance from the top" measurement, that it is not overfilled.. doing so can result in reduced life, and higher incidence of failure of the seals, when fully loading the bike ( my height/weight is similar to yours).
With the springs removed, and the bike jacked off the ground, allowing the forks to be fully extanded, that level (oil) should be 355mm (13.98") from the top of the fork tube., and both tubes should be equal.
I hope this helps.
Best of luck
« Last Edit: May 23, 2018, 07:21:17 pm by MAN OF BLUES »

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Offline m in sc

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Re: Fork seal replacement ineffective
« Reply #4 on: May 23, 2018, 08:13:30 pm »
it does and can play a role in sag when its weighted (he stated sitting ride height).

Offline esmoojee

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Re: Fork seal replacement ineffective
« Reply #5 on: June 03, 2018, 10:58:31 pm »
What’s the correct measurement for the 99? Anyone know?

Ed

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Re: Fork seal replacement ineffective
« Reply #6 on: June 03, 2018, 11:40:59 pm »
Here ya go.








Offline esmoojee

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Re: Fork seal replacement ineffective
« Reply #7 on: June 04, 2018, 02:55:52 am »
Thanks Bud!