Can You Clean Compression Damping Mechanism in Fork?

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Gitbox

Well-known member
Joined
Jun 16, 2014
Messages
129
Reaction score
25
Location
Maryland
I am currently rebuilding the forks on my 08 and am now at the point of cleaning and reassembly. Here is my question: is there any way to clean the compression damping mechanism at the bottom of the fork? It's never shown disassembled and I am not even sure it can be, but I want to make certain all the old junk is cleaned out of every part.

Thanks!

 
Last edited by a moderator:
You would have to remove the valve from the cartridge. They do unscrew from the bottom of the cartridge tube, though not easily If all you are doing is cleaning, I'd just flush the cartridges out with kerosene or ATF and call it good.

 
Wow. Someone changed my post title.
uhoh.gif


Thanks for the quick response but the mechanism I am referring to is at the bottom of the forks, facing rear, close to the axle hole - with the screw for adjustment. It is part of the bottom fork tube. Nothing to do with the cartridge.

 
The bottom of the fork contains only the compression bleed screw. All of the damping is in the cartridge.

As Fred says, the compression damping mechanism can be removed from the cartridge but it is secured with Red Loctite, so you need lots of heat.

 
Last edited by a moderator:
Wow. Someone changed my post title.
uhoh.gif

Thanks for the quick response but the mechanism I am referring to is at the bottom of the forks, facing rear, close to the axle hole - with the screw for adjustment. It is part of the bottom fork tube. Nothing to do with the cartridge.
Same answer as Fred gave for the low speed compression needle at the bottom of the forks.
smile.png


 
OK guys, thanks for the info.

So I'll just flush the bottom legs with kero and call it good.

I do wonder though, how does that screw adjust compression damping force? I can't see anything since it's buried in the fork leg. I do realize the damping is in the cartridge, but the adjustment is in the screw. What the heck does it do?

 
Last edited by a moderator:
kerosene is good...I use cheepo trans fluid in case all doesn't drain out...somewhat similar to fork oil

 
I have found that when I do the a couple of quick flushes with kerosene I like hanging the forks upside down over night. It's amazing how much more fluid comes out.

 
Last edited by a moderator:
I do wonder though, how does that screw adjust compression damping force? I can't see anything since it's buried in the fork leg. I do realize the damping is in the cartridge, but the adjustment is in the screw. What the heck does it do?
When the forks compress, fork fluid flows through a channel at the bottom of the forks. The screw restricts (adjusts) the fork flow through that channel slowing the fork's compression on small bumps and road imperfections (low speed compression damping). When you hit a big bump and the fork needs to compress very quickly, the compression damping in the cartridge opens up and acts like a relief valve allowing the fork fluid to flow pass it (high speed compression damping).

 
Thanks, MC. I did some more research and found the same answer.

It still would be nice to be able to remove and clean that area at the bottom of the forks since that is where most of the crud accumulates.

And, by the way, the forks are all back together along with a new tire and it rides like a new bike.
punk.gif


 
Top