My ‘77 GS750 is finally coming back together. I tore it down to address a number of safety concerns after riding it one day last fall.
Tires front & rear were weather cracked, steering-stem bearings shot, chain rusted, no rear brake installed, front brake barely worked, plus plenty of rust throughout & the fact that the bike wouldn’t idle.
These are my 3 final steps before I can take a test ride on the GS, to see how my improvements perform; as well as reveal what other surprises are still hidden preventing the GS from getting back on the road finally.
1. Install Rear Brake… well technically I could ride it before this is done, but not as safe of course.
2. Resolve new Electrical problem that has arisen.
3. Get Carbs back & installed.
1. Rear caliper frustrations. I had boughten this caliper off of eBay because one of the bleeders from my original caliper was stripped out. While I was rebuilding the eBay caliper, I managed to drop the caliper off of my work bench, onto my concrete floor. Afterwords, my banjo bolt wouldn’t thread back into the caliper because the caliper landed on the part where the banjo bolt threads in. So once again, my co-worker friend helped me out, he tapped the threads to make them round again. His advice was to always leave the banjo-bolt threaded in when the caliper is off the bike, to prevent something like this from happening again.

So last night after getting my caliper back from my co-worker friend, I was excited to install the caliper, braided-steel brake line & then bleed the rear brake. This would get me down to approximately 2 tasks before I can take the bike out for it’s first test ride this year.
After I got the brake & brake-line all installed, I went to bleed the rear brake. I ended up having a leak in my rear caliper while bleeding the inside bleeder! It was dripping onto the ground. This is getting frustrating… I’m anxious to take the bike out for a ride this year. But I know, piece by piece, I’ll get it there, plus it is rewarding working on the bike.
Off hand I’m not sure if when I separated the two halves of the rear caliper, upon reassembly, is there supposed to be some kind of a sealer or o-ring, I do not recall either of them when I dissembled the caliper. I just looked at the fiche on-line… it looks like there is likely an o-ring or something where the bolt threads into the caliper, to attache the 2 sides of the caliper together. Makes me feel a little dumb to not have noticed either way up assembly of the caliper. Well I’ll just separate the two sides of the caliper once again & check it out… hopefully I can get this resolved easily & then get it mounted back onto the bike w/o any leakage of brake fluid.

I will also need to come up with a way to mount the rear master cylinder reservoir… since the stock ‘77 750 reservoir is all one piece with the master cylinder. The master cylinder that I’m using now is from a GS1000 and these have a separate mounted reservoir. The original 750 master cylinder on this bike was junk from sitting so long that the brake fluid dried up inside of it. For now, I can at least bleed the brakes with the reservoir leaning up against the frame, and I can put the side panel back on the bike to pretty much hold the reservoir in place when I take it out for its test ride. In the end though, I should attach the reservoir somehow so it stays sitting flat, instead of leaning like it is now.

2. To install my new steering-stem bearings, I needed to completely pull the front-end of the bike off of it. So this meant that I needed to disconnect a number of the wires from the wiring harness, these wires all connecting inside the headlight bucket. Upon reassembly, the Ignition Switch Connector within the headlight bucket is messed up, when it wasn’t before I took it apart. Now, when I turn the ignition key, there isn’t any power to the bike at all. Electrical work is one of my strongest weaknesses, so this kind of sucks. By feeling around & moving/squeezing wires, I was able to track down where I needed to move/squeeze to get the power to come on, but it would cut out once I let go of the wire. It is the Ignition Switch Connector that seems to be causing my lack of power to the bike. Upon further inspection of this connector, I found that 1 of the 4 wires going into the connector was loose, and that I could actually just pull the wire out of the connector w/o any effort.

So off to my co-worker friend for advice, he told me how I can remove the little metal pin inside of the connector & then just solder the wire back onto that metal pin, and finally just re-install the metal pin & wire back into the connector. Well I haven’t soldered since I was a little kid, so I figured this is a good opportunity to relearn how to do that. I went & bought a basic soldering kit, & hopefully this resolves my electrical issue. One thing that makes me question if there is more then one wiring issue going on… when I squeezed the wires & there was power to the bike, when I turned my ignition key from the first position, to the 2nd (where I can actually start the bike), the power then cuts out again. I wonder if it’s possible that I might need to improve a couple other wires in the headlight bucket, but we’ll see as I progress along.
3. The last issue is still that I don’t have my carbs back from my co-worker friend. He has them because my Idle-Adjuster is broke from corrosion & me reefing on it to try & get it to turn. He says that he has been bidding on some racks of carbs, that he’ll snag me the idle-adjuster from one of them that he wins, plus he wants some additional carbs for his own needs. Once I get my carbs back, I can install them, & fire the bike up, presuming that I have my Electrical problem resolved. I am guessing that my jetting is fat (rich), based off of my plug readings last fall… but I never really did get to ride the bike much last fall, so we’ll see. The big test though is that when I’m able to turn up my idle speed, that I’m hoping the bike will actually idle on its own… it wouldn’t do that last year.
Oh, another form of frustration that I’ve been having when working on the bike is that all of a sudden this last week now, my radio station that I listen to in my garage doesn’t come in, it cuts in & out with mostly static… that has gotten real old.
But on the bright side, I did receive a bench grinder for my birthday from my wife, so that is cool. I’ve casually wanted a bench grinder for a few years now.