chain rubbing on inner side of rear shock

[RPC3]

Hi Guys, have a minor issue and was hoping for some advice and potential solutions. My 78 standard is mostly stock, but it came with some rear shocks that are obviously not stock. The bike came with a chain guard that was in pretty rough shape (corrosion/pitting/rust), and it looks like the chain had been rubbing on the inside of that guard. When I put a new chain on last year I removed the chain guard as it was really in bad shape (thinking maybe I could paint it), but decided to button the bike back up without it. At a rest/without a rider the chain has a solid amount of clearance from the shock, roughly 3/8" space (see photo). The chain also spins nice and freely, tension is adjusted so there is not any excessive slop in the chain.

That said, I've noticed microscopic metal flakes on my chain, turns out they're from the chain slowly rubbing the inside of my shock. All I can think of is that either the swing arm flex is allowing the chain to travel towards the shock (I have not done the metal bushing upgrade yet in the swing arm), but it doesn't feel like there's a lot (any) free play when I try to yank my rear wheel side to side. Regardless, my chain is rubbing on the shock and it's probably just as much a product of the shocks being a little oversized for the clearance available in that space.

I have no clue what the shocks are, there isn't any branding on them. They measure 12 1/2" or 12 3/8" from eye to eye, the diameter near the bottom of the shock base is 6 3/4" and the coil itself is 6" in diameter. The ride feels pretty good (I haven't ridden another xs650, so I can't really compare). The rubbing is happening at a very slow rate, probably dependent on how many hard turns I take per ride and I don't think it's putting the structural integrity of the shock or chain in any immediate danger, but clearly not good for long term wear. FWIW I'm only 160lbs so I shouldn't be taxing any pair of shocks on this bike, don't do any 2 up riding.

What would you do if this were your bike? Smaller diameter shocks? Swing arm bushings (don't really feel like doing that much labor at the moment, maybe this fall after the riding season), just throw the chain guard back on and let the chain rub on that instead? Excuse the dirt in the photos, due for a cleaning...

Thanks,
Rich

 

[5twins]

Those look like the shocks that came on my 650. They were actually a pretty nice shock with internal damping adjustment. There is a simple solution to your problem. Note the bottom eye in your 1st pic and how it is attached to the shock bottom offset. Simply flip the shock around so it steps out at the bottom instead of in like in your pic.

 

[RPC3]

Interesting, hadn't thought of that (or noticed). Do you think it'd be better to flip both shocks around so they're set up similarly? Only looks like it'd kick the shock out a degree or two at best so maybe not enough to make a difference.

 

[5twins]

I only set that side like that. The other was left stepped in. If that makes the shock lean in too much, you can shim the top out a little by placing some washers behind the top eye. I currently run some Konis and they have the same offset bottom eyes. I run them the same, left one stepped out, right one stepped in.

 

[RPC3]

Thanks again - you make it much easier to own an xs650, appreciate it.

 

[5twins]

I believe those shocks you have are the ProLift brand, at least that's what mine were. If you remove the springs, there should be 3 dampening adjustment settings. I ended up putting a normal single spring on mine from an old BMW shock, along with alloy spring covers.