GS650E '82 - warped rear disc?

[suziscrambler]

Hi GS owners!

First of all, what a great source of info this community is! I wanted to introduce myself as an owner of a GS650E 1982 model. I live in Australia and they are considered to be fairly rare bikes the GS650 series.

I have however, recently noticed a drive chain noise close to my counter sprocket. I have adjusted the chain to the correct slack, as well as align the swing arm as best I can. The noise only occurs in low speeds, say 20kmp/h. When I place the bike on the center-stand and rotate the rear wheel forward, I do hear some rubbing between the calipers and rear rotor on a particular part area of the rotor. Brake pads looks fine and evenly worn. I have two questions:

1. Can a warped rear disc mis-align the drive chain hence causing the rubbing sound at low speeds?

2. I have found a spare GS850G rear brake rotor. Will this be interchangeable on a GS650E?

Thanks

[tom203]

As to ?1.. I'd say no to warped disc causing chain noise

As to ?2... Part number 59210-18450 (rear disc) seems to be used on a bunch of models: see this parts fiche and backup to other years and models

http://www.partsoutlaw.com/oemparts/...a1f/rear-wheel

[steve murdoch]

Welcome to the site.
Has the rear brake caliper been cleaned and flushed in the last couple years.
Could be the piston isn't fully retracting and scuffing the rotor or maybe just the pads themselves binding up.
It doesn't make sense that the rotor contact would affect anything that would make a noise near the countershaft sprocket.
Easy enough to remove that cover and have a look.