Monoshock Spring Replacement

[Axel Bach]

Are there any specs on the 12R-22210-01-00 (Monoshock) .
I would like to know if it can be taken apart and have the spring replaced and/or the seals rebuilt ?
The length of the shock is about 14 inches, so the spring is about 9 1/2 inches.
Is there a chart that shows what kind of spring could replace the stock Yamaha one ?
Seems to be a need for these shocks as the aftermarket does not care nor recognize the fact that a '82-'83 XS400 came with a monoshock.
I would like to try and rebuild one ... if thats possible.

 

[Jeff0133]

Contact a company like progressive...
If it doesn't work out i can hook you up...I have one in very good shape

 

[Axel Bach]

I purchased two 12R-22210-01-00 so I have a replacement. I was just wondering what type/model of spring can replace the soft stock one.
My plan is to take one of them apart and rebuild it with a new spring/seals. Keep the other for a spare.
The one that was on the bike when I bought it, no longer rebounds... at all.

 

[JaredK]

This thread is a year old, but Axel, did you end up replacing the rear spring, and/or the whole shock assembly? Is it possible to take it apart and rebuild it?

I'm looking to swap the spring out with something a little bit stiffer. The current spring only has about 30,000km on it, and some surface rust on the coil, but it's a bit soft, especially riding one up. From the manual, here are the specs of the current spring:

Travel: 55mm (2.17”)
Free length: 234mm (9.21”)
K = 85.3 N/mm (8.7kg/mm, 487lb/in) / 0-33mm (0-1.30”),
K = 102.0 N/mm (10.4kg/mm, 582.2lb/in) / 33-55mm (1.30-2.17”)

I'll contact Progressive Suspension and see if they have any options.

I suppose a cheap/easier alternative could be to add a preload spacer?