1975 XS650. Fully stock head-to-toe, except a Pamco + e-advancer, and a solid-state regulator/rectifier.
Last year, I had this weird issue where every once in a blue moon the starter button wouldn’t work. I would push it, and either absolutely nothing happened, or I would hear a click. So I would just kick it. The starter gremlin eventually happened more often, to the point of where the starter button did not work 9/10 times. So I was kickstart-only for about a year. Bike always ran fine otherwise. Got really, really good at kickstarting!
So two months ago, I thought I should finally fix the starter issue by pulling out the safety relay and cleaning the contact. It already looked clean, weird. I simply put it back. It seemed to work because now everything worked fine.
But then two weeks ago, the start button stopped working intermittently again. OK, I thought, it may be the solenoid, I’ll get around to it soon. But then last week, the bike sputtered and died at idle in traffic. Starter button not working either, as in, no click, no response, nothing. Kicked it, but it was way more stubborn than usual. It kept sputtering. I found that revving it kept it “awake,” managed to get it home by keeping the revs above 2K. It sputtered very similar to having clogged carbs. So, I thought, OK, clogged carbs and a bad solenoid.
Cleaned the carbs, swapped the solenoid and the relay. Started right up, then when I revved, the bike gurgled then died. Pressed start again — no response at all. Kicked it, nothing. Waited a minute, start button suddenly works again, bike idles fine but sputtered, gurgled when revved, cylinders unevenly took turns not firing, then died.
These symptoms are really bizarre. The symptoms at first glance *act* like a combination of a dirty start button + clogged carbs + fouled plugs. But it’s not that.
I know this has to be an electrical issue, but I don’t know where to look. One thought could be the Pamco wiring, but that doesn’t explain the start button. Is it the main harness? Is it wiring near the kill switch? Does anyone have any ideas? Thanks!
PS: Here are all the things I troubleshooted below —
Probably not the Pamco, coil, plug cables or anything to do with timing. This is because the symptoms have usually been at the point of starting, as starter button doesn’t even respond sometimes.
Probably not the starter button itself, because the problem also happens when kickstarted, plus the horn works and the starter button *does* work sometimes.
Not the spark plugs. Bought new plugs.
Not the carbs. I cleaned the hell out of them, twice. They’ve also always have been synced and tuned to a T.
Not the grounding of the handlebars. The horn always works solidly.
Not the battery or its direct connections. I tried a fresh, new battery, triple-checked its connections.
Not a fuse issue, bike uses just one fuse for everything.
Not the solenoid. I bought a brand new replacement.
Not the safety relay. I bought a fresh N.O.S. replacement.
Not the key ignition assembly. Bought a replacement.
Last year, I had this weird issue where every once in a blue moon the starter button wouldn’t work. I would push it, and either absolutely nothing happened, or I would hear a click. So I would just kick it. The starter gremlin eventually happened more often, to the point of where the starter button did not work 9/10 times. So I was kickstart-only for about a year. Bike always ran fine otherwise. Got really, really good at kickstarting!
So two months ago, I thought I should finally fix the starter issue by pulling out the safety relay and cleaning the contact. It already looked clean, weird. I simply put it back. It seemed to work because now everything worked fine.
But then two weeks ago, the start button stopped working intermittently again. OK, I thought, it may be the solenoid, I’ll get around to it soon. But then last week, the bike sputtered and died at idle in traffic. Starter button not working either, as in, no click, no response, nothing. Kicked it, but it was way more stubborn than usual. It kept sputtering. I found that revving it kept it “awake,” managed to get it home by keeping the revs above 2K. It sputtered very similar to having clogged carbs. So, I thought, OK, clogged carbs and a bad solenoid.
Cleaned the carbs, swapped the solenoid and the relay. Started right up, then when I revved, the bike gurgled then died. Pressed start again — no response at all. Kicked it, nothing. Waited a minute, start button suddenly works again, bike idles fine but sputtered, gurgled when revved, cylinders unevenly took turns not firing, then died.
These symptoms are really bizarre. The symptoms at first glance *act* like a combination of a dirty start button + clogged carbs + fouled plugs. But it’s not that.
I know this has to be an electrical issue, but I don’t know where to look. One thought could be the Pamco wiring, but that doesn’t explain the start button. Is it the main harness? Is it wiring near the kill switch? Does anyone have any ideas? Thanks!
PS: Here are all the things I troubleshooted below —
Probably not the Pamco, coil, plug cables or anything to do with timing. This is because the symptoms have usually been at the point of starting, as starter button doesn’t even respond sometimes.
Probably not the starter button itself, because the problem also happens when kickstarted, plus the horn works and the starter button *does* work sometimes.
Not the spark plugs. Bought new plugs.
Not the carbs. I cleaned the hell out of them, twice. They’ve also always have been synced and tuned to a T.
Not the grounding of the handlebars. The horn always works solidly.
Not the battery or its direct connections. I tried a fresh, new battery, triple-checked its connections.
Not a fuse issue, bike uses just one fuse for everything.
Not the solenoid. I bought a brand new replacement.
Not the safety relay. I bought a fresh N.O.S. replacement.
Not the key ignition assembly. Bought a replacement.
