So little brother went for a long ride this afternoon after I put his 80G back on the road. He came back complaining that it was intermittently running okay and then missing really bad. His girlfriend said she could smell gas while riding behind him, and he wanted me to go back into his carbs.
I was pretty sure I had the carbs right, so I pulled the plugs instead. 1 and 4 looked fine, but 2 and 3 were wet and looked like they weren't firing. It's got brand new Dyna DC1-1 coils, so I pulled the plugs on the TCI and checked the resistance to the pickup coils. The resistance looked a little higher than it should, but it was the same on both pickups.
Since the resistance wasn't in spec, I pulled the timing cover off, and found something interesting. There's a little clip where the wires enter under the timing cover, and that clip is supposed to hold the wires. The wires were not in the clip, and one of the pickup coil wires was resting against the timing wheel. I felt around on that wire, turned it over, and sure enough there was a bare spot that had just worn through enough to expose the wire.
I opened the clip up, put the wire where it was supposed to be, and put a little electrical tape over the bare spot. It must have been jiggling around in there and intermittently shorting out on the timing wheel, but with the wires held by the clip they won't be able to get close to the timing wheel again. He took a little ride to test it and said it was running like it should again.
Total time to fix - about ten minutes. The look on his face was priceless. Kind of a "I've been riding around on two cylinders all afternoon, and that's all that was wrong with it?!" type look.
I'm still a little concerned about the higher than spec resistance readings at the tci, though. They were reading about 800 ohms, and they should be 720. I'm thinking that additional resistance may be due to old parasitic electrical connections, and since I just bought a couple terminal kits from Cycleterminal.com, I might just go ahead and replace all the electrical connections.
Those kits are nice. One comes with 100 2.8mm tin plated brass terminals plus a bunch of connectors, and the other one comes with 80 6.3mm brass terminals and connectors. When you start rewiring those 35 year old plastic connectors a lot of times the plastic is kind of crumbly, so I much prefer to put new connectors on. And they even come with a terminal extraction tool.
Anyway, this is what the kits look like -
2.8mm kit
6.3mm kit
I was pretty sure I had the carbs right, so I pulled the plugs instead. 1 and 4 looked fine, but 2 and 3 were wet and looked like they weren't firing. It's got brand new Dyna DC1-1 coils, so I pulled the plugs on the TCI and checked the resistance to the pickup coils. The resistance looked a little higher than it should, but it was the same on both pickups.
Since the resistance wasn't in spec, I pulled the timing cover off, and found something interesting. There's a little clip where the wires enter under the timing cover, and that clip is supposed to hold the wires. The wires were not in the clip, and one of the pickup coil wires was resting against the timing wheel. I felt around on that wire, turned it over, and sure enough there was a bare spot that had just worn through enough to expose the wire.
I opened the clip up, put the wire where it was supposed to be, and put a little electrical tape over the bare spot. It must have been jiggling around in there and intermittently shorting out on the timing wheel, but with the wires held by the clip they won't be able to get close to the timing wheel again. He took a little ride to test it and said it was running like it should again.
Total time to fix - about ten minutes. The look on his face was priceless. Kind of a "I've been riding around on two cylinders all afternoon, and that's all that was wrong with it?!" type look.
I'm still a little concerned about the higher than spec resistance readings at the tci, though. They were reading about 800 ohms, and they should be 720. I'm thinking that additional resistance may be due to old parasitic electrical connections, and since I just bought a couple terminal kits from Cycleterminal.com, I might just go ahead and replace all the electrical connections.
Those kits are nice. One comes with 100 2.8mm tin plated brass terminals plus a bunch of connectors, and the other one comes with 80 6.3mm brass terminals and connectors. When you start rewiring those 35 year old plastic connectors a lot of times the plastic is kind of crumbly, so I much prefer to put new connectors on. And they even come with a terminal extraction tool.
Anyway, this is what the kits look like -
2.8mm kit
6.3mm kit
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