BannedCR500Riders.com

Plain old white vinegar works fantastic.
Plug up the ends and let it soak.
You can also use it to loosen up
the gunk that is in water pump area.
Be careful with the mag covers as it
will eat the mag. Doesn't hurt aluminum.

The best I have used is a Regina o-ring
but twice maybe three times the cost of your primary
drive from rocky mountain. I have an older primary
drive chain on my CR500 and am very happy with
the wear and lack of stretching. I have not tried
the newer (last 2 years) ones.

I have a 2000 service honda that fits me better than the 450 based bikes.
I am 5-9 with 30" inseam. More work to do 450 but better for your size.

That looks like a 87-88 shock that someone installed a remote reservoir on.
Maybe from an XR?