Manitou Mars fork only springs back up to about 80% of its travel regardless of air pressure?!

PB Forum :: Mechanics' Lounge
Manitou Mars fork only springs back up to about 80% of its travel regardless of air pressure?!
  • Previous Page
  • Next Page
Author Message
flag shredthegnarnia
O+
Posted: Mar 24, 2017 at 9:46 Quote
So I'll admit, I built a bike up with a fork of unknown history.

On the shakedown ride, I noticed that there was a lot of noise/fork feedback whenever I'd pull up/wheelie. Upon further inspection, I realized the fork was only working thru about the top 80% of travel, sitting at 20% sag or so, even unweighted.

In fact, in order to get the fork to fully telescope, I had to PULL it apart. Again, the top 80% is working pretty much as expected.

So I got home, found the manual: https://www.manitoumtb.com/wp-content/uploads/2016/06/2001-Mars-Service-manual.pdf, and took apart the TPS to find no oil in it. Unsurprising. What is surprising is that after filling it to spec with 10 weight fork oil (5 is recommended but I only had 10 sitting around from my motorcycle), and airing back up (to 200psi, even!), the problem persists, and I have to pull it EVEN HARDER to get full telescoping!

Yes, I used the wrong oil, but it's heavier, so if anything the 10 weight should make that bottom portion even more resistant.

Any ideas?
flag Mike87
Posted: Mar 24, 2017 at 14:24 Quote
Did you take the air spring apart? If not I suspect that you have too much negative air in the spring. It may need a new seal as well.

Knowing that the damper had no oil, it might be possible that the fork has had a hard life and will require a complete rebuild to get it to perform as it should.
flag shredthegnarnia
O+
Posted: Mar 24, 2017 at 19:35 Quote
Mike87 wrote:
Did you take the air spring apart? If not I suspect that you have too much negative air in the spring. It may need a new seal as well.

Knowing that the damper had no oil, it might be possible that the fork has had a hard life and will require a complete rebuild to get it to perform as it should.

I only took it apart to where i could see inside the positive air reservoir
  • Previous Page
  • Next Page

 


Copyright © 2000 - 2024. Pinkbike.com. All rights reserved.
dv42 0.015304
Mobile Version of Website