2010 X31 250cc Fork information, found some stuff out

brentn · 08-22-2010, 04:32 PM

Anyone who cares about slightly improving the forks on these things, listen up.

Last night I went all out and did some research on my girlfriends forks, took them all apart and measured the amount of fluid in each on.
These are the forks for the little wheel version of the 2010 x31, I don't know if they differ from the larger wheel's forks at all.

Each fork contained about 200ml of fork fluid, which looked like diarreah when I finally got it all out.
To get the forks apart remove the end caps and stick a wrench on the damping rod nut underneath the fork cap. Hold the wrench and then remove the cap.
Remove the nut on the damping rod that secures the spring in place and then the spring can come out.
I found the spring was wedged in there really good, but if you pull hard enough it will come out, keep trying.
With the spring out dump the fluid out into a container, and pump the damping rod up and down until there is no resistance and all you can hear is air pumping, you should get about 200ml of fluid at this point.
I filled my fork with 225ml of fluid to see how it affects dampening, when you fill the fork go in stages as it cannot hold all the oil until some of it is pumped into the shim stack.
Pull the rod the full length up and down and add more fluid until all the fluid is added. You'll have bled all the air out when the damping rod no longer makes any air bubble noises and it is hard to pull up throughout the entire stroke.

When that's all done install the spring and bring the damping rod back up to the top, slightly compress the spring to get the buffer, washer and then the nut back on.
I found that the nut should only be installed ONE INCH onto the threaded damping rod, it can go farther but then you increase the spring pressure. If you want more spring pressure then put the nut on more just remember to keep both forks consistant.

Install the end cap and then thread the cap back onto the outer tube, your done.

These forks btw, are fully rebuildable!!! Which is great news, you should not have to pay 250$ for new forks just cause the seals are blown. The retaining clips for the fork seals are easily removable, unlike the Orion forks that I worked with before.

Weldangrind · 08-23-2010, 12:42 AM

Excellent tutorial, thanks!

Where would you find replacement parts?

08-22-2010, 04:32 PM	#1
brentn Join Date: Aug 2010 Posts: 26	2010 X31 250cc Fork information, found some stuff out Anyone who cares about slightly improving the forks on these things, listen up. Last night I went all out and did some research on my girlfriends forks, took them all apart and measured the amount of fluid in each on. These are the forks for the little wheel version of the 2010 x31, I don't know if they differ from the larger wheel's forks at all. Each fork contained about 200ml of fork fluid, which looked like diarreah when I finally got it all out. To get the forks apart remove the end caps and stick a wrench on the damping rod nut underneath the fork cap. Hold the wrench and then remove the cap. Remove the nut on the damping rod that secures the spring in place and then the spring can come out. I found the spring was wedged in there really good, but if you pull hard enough it will come out, keep trying. With the spring out dump the fluid out into a container, and pump the damping rod up and down until there is no resistance and all you can hear is air pumping, you should get about 200ml of fluid at this point. I filled my fork with 225ml of fluid to see how it affects dampening, when you fill the fork go in stages as it cannot hold all the oil until some of it is pumped into the shim stack. Pull the rod the full length up and down and add more fluid until all the fluid is added. You'll have bled all the air out when the damping rod no longer makes any air bubble noises and it is hard to pull up throughout the entire stroke. When that's all done install the spring and bring the damping rod back up to the top, slightly compress the spring to get the buffer, washer and then the nut back on. I found that the nut should only be installed ONE INCH onto the threaded damping rod, it can go farther but then you increase the spring pressure. If you want more spring pressure then put the nut on more just remember to keep both forks consistant. Install the end cap and then thread the cap back onto the outer tube, your done. These forks btw, are fully rebuildable!!! Which is great news, you should not have to pay 250$ for new forks just cause the seals are blown. The retaining clips for the fork seals are easily removable, unlike the Orion forks that I worked with before.
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08-23-2010, 12:42 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Excellent tutorial, thanks! Where would you find replacement parts? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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