Suzuki GT380 - Electrical issues

[eithr]

So, as some of you are aware, my clutch cable snapped on me a couple of weeks back. I ordered a new cable and was beside myself with excitement after installing the cable without much trouble this past Friday after work. I put about 30 miles on the bike before parking it at a friend's house for the weekend. He insisted I ride his more modern GS500 for our ride to and from the Indianapolis Speedway to watch the GP race (ride was from Columbus OH to Indianapolis IN).

That evening, after 6 hours of saddle time and over 12 hours of being outdoors, I hopped on my GT380 to ride home from my friend's house. I got a few miles into the ride, pulled up to a stop light and the bike shut down, all lights went out. It wouldn't start back up. Walked the bike into the nearest parking lot and diagnosed the issue - ground wire had worked itself loose and while fiddling with it, pretty sure I blew a fuse.

I'm just starting to get a grasp of understanding the other systems on the bike... I have no idea how the electrical system works on this thing, but replacing/repairing the ground wire/connection seems fairly straightforward. But, I'm lost about the fuse(s). Anyone mind giving me a summarized explanation of the fuse system? Pretend I'm completely clueless. When replacing fuses, are there different kinds? If so, what should I be looking for? Any reliable sources, online, I can order some from?

Much thanks.

[rbond]

I don't know how many fuses you have, most older bikes had one for everything. There is the AMP rating pressed into one of the silver end caps. 15 AMP is a common size, also maybe a 20 AMP. They are plain glass fuses you can get almost anywhere, WalMart, auto parts houses, etc. If replacing the fuse brings life back, but it won't seem to charge the battery anymore, first culprit could be the rectifier, then maybe the regulator. When the ground let go, it may have fried one or both, if you have any further problems that is. You might just need a fuse nad be on your merry way...

[eithr]

I don't know how many fuses you have, most older bikes had one for everything. There is the AMP rating pressed into one of the silver end caps. 15 AMP is a common size, also maybe a 20 AMP. They are plain glass fuses you can get almost anywhere, WalMart, auto parts houses, etc. If replacing the fuse brings life back, but it won't seem to charge the battery anymore, first culprit could be the rectifier, then maybe the regulator. When the ground let go, it may have fried one or both, if you have any further problems that is. You might just need a fuse nad be on your merry way...

Ugh. Now I'm scared. I have no idea what the rectifier or regulator do. If one or both turn out to be 'fried' what might that mean and how siginficant an issue will the repair be? Would I need to replace stuff? Are necessary parts easily available or am I in for a treasure hunt?

Man I thought I was doing good finally starting to grasp at understanding the other systems. I was not prepared to have to learn the electrical and charging systems this soon.

Thanks for the info on the fuses, definitely helpful.

*Edit*
Did some research, so now I understand what the rectifier and regulator do, but still a little clueless as to how to repair, if necessary. Time to dig thru the threads, but feel free to pass along any knowledge. This newb is doing a lot of learning this summer trying to keep my bike on the road.

[rbond]

The rectifier changes the AC current from the alternator to DC current to regulator, then the battery. I have not looked at the setup on a 380, but if the same as my GT500, a rectifier can be obtained from Radio Shack for about $5.00. The regulator or if you have a combination rec/reg unit can probably be gotten from a guy in Oregon who specializes in these for motorcycles. There is also Electrex in England that can help too. It is really is not scary, but can be time consuming tracking down electrical gremlins.

[eithr]

The rectifier changes the AC current from the alternator to DC current to regulator, then the battery. I have not looked at the setup on a 380, but if the same as my GT500, a rectifier can be obtained from Radio Shack for about $5.00. The regulator or if you have a combination rec/reg unit can probably be gotten from a guy in Oregon who specializes in these for motorcycles. There is also Electrex in England that can help too. It is really is not scary, but can be time consuming tracking down electrical gremlins.

Cool. That is helpful. I'm really hoping that just reattaching the ground and replacing the fuse (if necessary) will solve the problem. After we realized the issue was the detached ground wire, we touched it to the frame and got the lights to come back on for a moment. So, then we tried to secure the wire in place, at least enough to get home, but we got some small sparks then nothing. My buddy assumed we just blew the fuse.

He's wanting to pull the whole wiring mess apart this winter and just completely rewire the bike. Has anyone done this? Built a homemade wiring harness and etc? Any helpful resources? Advice?

[rbond]

I replaced the wiring harness for the ignition part from the stator to the CDI and changed the connectors from the charging coils. The problem is color coded wires. If you do not get factory color coded wires, then it becomes a matter of 'translating' the factory connections to whatever scheme you are using. Keeping it straight in your head and paper can mess with your mind. Take your time and document carefully. It is not rocket science!

[eithr]

Woo-hoo! Replaced the fuse, rerouted the wiring a little, cut and exposed some fresh wire on the ground, crimped it into a new ring doodad, tightened everything into place, kick kick kick, ZING! the Suzuki is alive once again.

My buddy tells me that my ground wire set-up looks a little sketchy. Any one have a photo of their ground wire set-up for comparison?

[Craig380]

Nice job

Haven't got a photo but my main ground from the battery negative is under one of the screws that holds the air filter box in place (just under the back of the fuel tank).

I found it's best to scrape any paint there back to bare metal so the ring connector can make the best earth.

[Coyote]

There should be 3 major grounds. The one that craig described, another bare braided strap that runs from battery neg to any convenient bolt on the motor. Mine mounts near the kicker.
The third is a small wire often overlooked. It runs from one of the coil pack mounting bolts to the front - center cylinder shroud screw.

[eithr]

There should be 3 major grounds. The one that craig described, another bare braided strap that runs from battery neg to any convenient bolt on the motor. Mine mounts near the kicker.
The third is a small wire often overlooked. It runs from one of the coil pack mounting bolts to the front - center cylinder shroud screw.

Cool. Definitely helpful. I'm just getting into figuring out the electrical system and identifying parts and whatnot. I had no idea about the third ground running from the coil to the center cylinder; I'll look for it later to help with my cataloging of everything in my head.

The weekend problem was with the negative (I think) ground. On my bike, it's set up so that that wire leads from the battery into a pinched piece of metal with a ring on one end. The ring is bolted to a bridge of metal between the frame rails just behind the fuel tank. Does that sound correct? It's a 1976 model. My friend wants to spend some time this winter replacing pretty much all the wiring and soldering the grounds into place (if I understood him correctly). Thoughts?

[Craig380]

The weekend problem was with the negative (I think) ground. On my bike, it's set up so that that wire leads from the battery into a pinched piece of metal with a ring on one end. The ring is bolted to a bridge of metal between the frame rails just behind the fuel tank. Does that sound correct? It's a 1976 model. My friend wants to spend some time this winter replacing pretty much all the wiring and soldering the grounds into place (if I understood him correctly). Thoughts?

That bridge is where the air filter box should bolt, that's a good frame ground. It's probably worth soldering the ground wires to the connectors, but not soldering the connectors to the frame.

Also, while the GT550 and 750 triples will have a fat braided ground strap from battery -ve to the motor (because both have electric starters), I've never seen that on a 380 (no electric start = less current draw). Probably wouldn't hurt any, though ....