Weird problem after rear brake locking up

[TheFieryMan]

I have been doing much needed caliper rebuilds on my 82 Aspencade. Fronts went great and rear went fine as well but while test riding I found that the rear brake was still dragging hard and nearly locking up. That happened a couple times before but I attributed it to the rear caliper. But after rebuilding it, it still had the same issue. So, now I suspect the rear master cylinder. In any case had to get it home but that caliper got very hot and smoked pretty bad. I let it cool down outside for a couple hours and went out to pull it in the garage. Thats where the weird problem started.

I went to start it and it just clicked and dropped all voltage. Tried again there's no voltage. No lights no dash lights. Nothing, then it comes on super dim, then suddenly full on. I go to start it and it just clicks again and losses all voltage again. After closer inspection I can hear that its the Stater solenoid/Main fuse that makes the click sound. Is it possible that heating up that rear brake caliper and rotor some how damaged the starter solenoid/main fuse module? The fuse is fine and there is no corrosion on any of the contacts. I made sure there is good connection on all the different contacts.

[Track T 2411]

The brake issue sounds like a clogged 'spooge' hole in the rear master cylinder. If you're not familiar with it, it's a tiny hole next to the larger fluid supply hole in the master cylinder body. It's pretty common for it to clog up over time.
Another cause could be a sticking brake pedal, or a combination of the two. If the brake pedal is sticking, the brake light would stay on, drawing constant power. I can't think of any other relationship between that and the electrical issue you describe.

[TheFieryMan]

The brake issue sounds like a clogged 'spooge' hole in the rear master cylinder. If you're not familiar with it, it's a tiny hole next to the larger fluid supply hole in the master cylinder body. It's pretty common for it to clog up over time.
Another cause could be a sticking brake pedal, or a combination of the two. If the brake pedal is sticking, the brake light would stay on, drawing constant power. I can't think of any other relationship between that and the electrical issue you describe.

The pedal is fine. Brake light comes on when pressed and goes off when released. I have the rebuild kit for the rear master cylinder which I planned to do today but now I'm tracking this issue down.

Battery is reading 12.5V at rest and when the key is on.

I just ordered a new starter solenoid which should come tomorrow.

[Rambozo]

Power issue sounds like a bad/dirty connection on a main power or ground wire. Works on low current but high current arcs and breaks the connection. You can trace it with a volt meter or just inspect and clean all of them. Probably long overdue anyway.

[TheFieryMan]

Power issue sounds like a bad/dirty connection on a main power or ground wire. Works on low current but high current arcs and breaks the connection. You can trace it with a volt meter or just inspect and clean all of them. Probably long overdue anyway.

I immediately thought the same so I checked all the related connections and they are all good. I'm an electrician and an old 12V car audio guy so Im pretty knowledgeable in this area. My Fluke multimeter is like an extension of me. Ha ha.

[TheFieryMan]

Well I solved it but this was a weird one. Battery was reading about 12.6V consistently whether the key was on or off. All connections were good and continuity tested normally on everything. I had just been using it right before I had this issue so I knew there was no way the battery was the problem.

It was the battery.

I grabbed another battery I had sitting around and the bike started right up. I took the old battery to a couple different parts stores to be load tested and they were so confused how it would read 12V and then drop to zero as soon as they put a load to it. Then it would come right back up to 12.6V.

$130 later I have a battery.

[Track T 2411]

Batteries can do some weird stuff, all right. I am curious, does the bike still have the 'dogbone' main fuse? If so, I would change it out with a modern blade fuse/ holder. It may not have contributed to the battery issue, but those fuses can be unreliable and cause some funky electrical issues. My 2 cents...

[TheFieryMan]

Batteries can do some weird stuff, all right. I am curious, does the bike still have the 'dogbone' main fuse? If so, I would change it out with a modern blade fuse/ holder. It may not have contributed to the battery issue, but those fuses can be unreliable and cause some funky electrical issues. My 2 cents...

No it was changed to a normal fuse by the previous owner.