Is my brake master cylinder OEM?

[stanky]

I'm having trouble identifying if my set up is stock (new owner of the bike). I'm trying to order a rebuild kit for my master cylinder due to bad pressure (system has been bled multiple times, it's just old as hell and i figure it needs a rebuild) and I'm seeing conflicting things when Look at the parts breakdown on bikebandit. On bike bandit it shows a square style master cylinder with a sight glass for this motorcycle, but you'll see in the pictures that I have a different style master cylinder reservoir. Were there different applications for different bikes? Clarification would be great.

The bike is a 1981 GS650G
Sorry for the picture quality, I had to zoom in on pictures I already had.

[Nessism]

The original master for your bike should use a rectangular reservoir according to the OEM parts fish such as on Partzilla.com

[stanky]

That's what is confusing me. I don't really want to buy a new master cylinder set up if I can just do the rebuild instead. It seems the 1981 GS650L had a master cylinder with a round reservoir. Is there any identifiers on the cylinder or brake set up itself that would help me identify what I have?

Thanks for the quick reply.

[salty_monk]

If I was you I'd just pick up a 2nd hand EX650 one from Ebay. Cheaper than a rebuild & better to.....

Note the newer EX one would work too but doesn't have a mirror mount. https://www.ebay.com/itm/32470672167...oAAOSwLiVg5mZZ

https://www.ebay.com/itm/334124345962?hash=item4dcb5cea6a:g:ciUAAOSwt-lhJGsF

[stanky]

Thanks for the suggestion. I'll look into it.

[rphillips]

Hey stanky, where in Tennessee, it's a lonnng state??? & salty, will the Kawa. master have the switch for the brake light??

[phydeauxmutt]

Is there a chance that your bike is really a GL?

If you don't have a picture of the bike, please answer a few questions.
1. Front axle. At the bottom of the forks or in front of the bottom?
2. Front fender. Chrome or painted?
3. Headlight. About 6" across or 7" across (the glass)?
4. Fuel tank. A rounded rectangle or fully-rounded "peanut" tank?
4a. Tank capacity?
5. Seat. Straight or stepped?
6. Tail light. Covered by a tail fairing or bolted to the fender?
7. Rear fender. Plastic or chrome?

[stanky]

Hey, sorry for the late reply. I took some pictures, but the site won't let me upload them as they are "too large".

https://ibb.co/0r5nqff

https://ibb.co/DfN1qLW

https://ibb.co/YbMbrGM

Those three links show side/front/rear profiles. By all metrics it is a G650G. I'm hoping it's not a frankenstein. Let me know what you think!

Also @rphilips: I'm in chattanooga.

[adamdaz]

This is all interesting. Your front master cylinder is identical to mine, but I have a gs650gl. One thing that I see often is that the 81 model year is different from the 82-83 model years for some parts for the gl. Maybe that true for your g?

[Who Dat?]

It's a little hard to see, but it's possible that the angle of the master cylinder bore does not match with the G handlebars. It appears that it is angled with the outlet downward, indicating that it's meant to mount on handlebars that would make it more level. Like GL bars.

Your M/C is likely OEM Suzuki, but not for that particular bike.

One other thing to note: the GL versions of the 650 only had a single disk, which takes a smaller m/c. As others have suggested, it might be best overall to just source a new unit.