yz490 -82 rear gas reservoir?

[svante]

hi all

rebuilding an old yz490...
has anyone tried to rebuild the original rear shock absorber?
Im to stingy to buy a new ohlins for several $$$
so...
the damper was no problem but how to open the gas container?
bottom end of the cylinder seems to be removable but
I think it contains a rubber bladder with 150 psi of nitrogen?
which I have to drain without damaging it?
there is a small M3 hole at the bottom, perhaps its a valve inside?
anyone with experiences?
or has anyone an old damper to use violence on
drill a hole and remove the bottom end and tellme whats inside...*S*

[nexus446]

I had my original KYB rear damper rebuilt and the nitrogen reservoir was drilled to relieve any residual pressure then a aftermarket recharge valve was installed in place of the old screw, I had trouble obtaining a new seal head assy for mine but got one in the end from a local suspension rebuilder. I have 3 spare shocks in parts but most bits are unusable, it seems the shock shaft is prone to pitting and corrosion and good condition ones are getting harder to come by now.
Chris

[svante]

hi

thanks for tips, today I succeded with making gas reservoir working.
I installed a tyre valve and filled the reservoir half with damper oil(behind the wall) and filled it up to 150 psi....

but the bike is still to soft...
maybe the shock spring is to soft for a 250 pounds driver like me...

and the adj screw at the top is only affecting the damper very little....
almost unoticeable difference between full in or out....

thanks....