Monolever rear shock

[Olliepup]

I have an R65 1986 monolever with 35,000 miles. When I sit on the bike, the rear suspension drops several inches and stays there. It will come back up in a few seconds, when riding, but not if I just remove my weight from the bike. It seems to suffer from acute stiction. I've had the bike two years and think it's always been this way (since I've owned it). This doesn't seem normal and I feel the shock may be worn out. A new Progressive spring and shock is about $500, while Max BMW sells the OEM shock alone for around $175. My rear spring and shock appears to be the original OEM unit and the bike shows no signs of abuse.
Any thoughts...is the shock worn out? Is it smart to just replace the shock and save a gob of money? If it is a stiction issue, can this be fixed?
Thanks, Dave

[Bob_Roller]

Not familiar with the monoshock bikes, does it look like the shock absorber may be rebuildable ?

I'm thinking that most BMW OEM shocks are not rebuildable .

There's probably not too much you can do  to a 26 year old shock absorber, except replace it .

This is one of those parts that if you get a good quality part that is rebuildable, you probably will never need to replace it again, just change seals and refresh the oil .

Just did a quick check of aftermarket shocks for your bike .

IKON P/N : 3610-1020, $570US .

Hagon P/N : M60004, $394US .

OEM may be the most cost efficient way to go .

[Barry]

I think the first thing I would do is remove the shock and compress it off the bike to test for stiction. Then at least you will no if the problem lies in the shock or the shock mountings/swinging arm.

If it is the shock I'd be tempted by the OEM item. Can the progressive shock be 3 times better ?

[Olliepup]

Testing the shock off the bike is a good idea. I'll do that. The Progressive shock is the whole unit, while the Max BMW part I quoted is just the shock and not the spring.
Thanks, guys, Dave