I’ve been restoring old motorcycles for about four years now, mostly as a weekend hobby in my cramped garage. My latest project is a 1972 Honda CB350 that I picked up for cheap, but the previous owner had already torn it apart and lost half the hardware. I’m finally at the point where I need to focus on the wiring and lighting, and that’s where I keep hitting a wall.
I’ve tried using a standard multimeter to trace the original harness, but the colors are so faded I can barely tell the blue from the green. I also bought a cheap aftermarket wiring kit from a no-name brand on eBay, and honestly it felt like the instructions were written in another language. Not sure if this matters, but the bike came with a mismatched taillight assembly from a Yamaha, so I’m guessing the previous owner was just cobbling things together. My budget is tight—maybe $50 to $80 max for additional parts—and I only have basic hand tools, a soldering iron, and a lot of patience. I’ve considered replacing the entire harness with a universal unit, but I don’t want to lose the original look or make a mess of the connections.
The biggest headache is the lighting circuit. The headlight flickers when I rev the engine, and the turn signals stop working after a few minutes. I swapped the battery with a new Yuasa AGM model, and the charging system seems to put out around 13.8 volts at idle, so I don’t think that’s the issue. I’ve also checked the grounds—cleaned every connection with a wire brush—but the problem comes back after a short ride. It’s starting to feel like a ghost in the machine, and I’m not sure if I’m missing something obvious or if I should just start from scratch with a modern LED setup.
Has anyone dealt with a similar gremlin on these old Hondas? I’m open to trying a simple test like isolating each circuit with a basic switch, but I’d rather not mess up the vintage vibe. What’s your go-to method for tracking down intermittent electrical faults without blowing your budget?
I’ve tried using a standard multimeter to trace the original harness, but the colors are so faded I can barely tell the blue from the green. I also bought a cheap aftermarket wiring kit from a no-name brand on eBay, and honestly it felt like the instructions were written in another language. Not sure if this matters, but the bike came with a mismatched taillight assembly from a Yamaha, so I’m guessing the previous owner was just cobbling things together. My budget is tight—maybe $50 to $80 max for additional parts—and I only have basic hand tools, a soldering iron, and a lot of patience. I’ve considered replacing the entire harness with a universal unit, but I don’t want to lose the original look or make a mess of the connections.
The biggest headache is the lighting circuit. The headlight flickers when I rev the engine, and the turn signals stop working after a few minutes. I swapped the battery with a new Yuasa AGM model, and the charging system seems to put out around 13.8 volts at idle, so I don’t think that’s the issue. I’ve also checked the grounds—cleaned every connection with a wire brush—but the problem comes back after a short ride. It’s starting to feel like a ghost in the machine, and I’m not sure if I’m missing something obvious or if I should just start from scratch with a modern LED setup.
Has anyone dealt with a similar gremlin on these old Hondas? I’m open to trying a simple test like isolating each circuit with a basic switch, but I’d rather not mess up the vintage vibe. What’s your go-to method for tracking down intermittent electrical faults without blowing your budget?
