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This is not a plea for help, but a recap of today's round of diagnosis and resolution for starting problems on IndyBob's '83 GS1100E -- I figure it might be useful for someone. It also illustrates that there's quite often more than one thing wrong at a time, especially with older machinery.
Problems:
- Poor cranking speed, sometimes no cranking
- Gawdawful "CLACK" noise sometimes from inside the engine when starting
- Intermittent starting -- acts as if starter button isn't making contact, then fires randomly.
We first pulled the stator cover to investigate the starter clutch mechanism. This is a known weak spot -- the three small 8mm bolts holding the starter clutch to the back of the rotor sometimes stretch then back out, with potentially disastrous consequences. We thought the "CLACK" noise might be an early indicator of this problem.
All was found to be well with the starter clutch.
Since the stator cover was off and the gears were out of the way, we tested the starter motor with a known good battery and a set of small jumper cables. The starter spun powerfully, freely and quietly.
Mmkay, nice to eliminate two potentially expensive problems, but that's also two leading theories shot down...
After replacing the stator cover and gasket, we turned our attention to the rest of the electrical system.
With the key off, the battery read a healthy 12.8 volts. However, with the key on, the voltage immediately dropped below 12V, to around 11.5V, and dropped slowly from there.
When trying to crank the engine, voltage dropped well below 9V, and the engine barely turned before giving up altogether.
Using the good battery and jumper cables as a booster, we saw an improvement in cranking speed, but it still wasn't good.
Around this time, we happened to discover that the clutch safety switch was intermittent, which explained that part of the issue. (Easy to bypass or replace with a $10 part)
Operating on the theory that there was some electrical drain and/or a bad connection, we then removed the headlight, tank, and airbox, and spent a pleasant hour or so cleaning all the connectors on the bike (with DeOxit spray, mostly), then reassembling with dielectric grease.
Several lightly corroded connections were found, and the main connector from the stator to the R/R (containing the +12V wire and the three stator wires) was found to have heavy corrosion. We disassembled this connector completely in order to scrub out every bit of the green gunk.
We also found and corrected a loose connection to the battery positive terminal. 
Since we were in the neighborhood, we tested the stator with an ohmmeter, and it tested good: resistance between each pair was the same -- .7 ohm -- with no continuity to ground. (In other words, test stuff whenever the opportunity arises... information is always good, even though the stator doesn't directly affect starting.)
Upon testing, voltage drop with the key on was now acceptable (after all the abuse, the battery read 12.7V at rest, and 12.4V with key on). Cranking was now vigorous, and cranking voltage was around 12.0V.
Conclusions:
- The corroded connections, especially the main power connector from the R/R, were not allowing full power to the wiring harness.
- The loose battery connection seemed to be the primary cause of the weak starting and low-voltage issues
- We probably dodged a bullet big-time by catching the corroded stator connections.
- The starter safety switch is the same crappy low-rent design as the brake switch. I bypassed it on my bike years ago, and we coped on Bob's bike by simply jiggling the clutch lever a bit when the starter button didn't seem to work. This will eventually need to be fixed or bypassed for real, of course.
- Voltage at the ignition coils was still a tad low, although the bike ran fine -- the only electrical connections we couldn't easily clean today were the contacts in the ignition switch itself. We'll address this in the near future.
- The bike arrived at my house on a trailer, but Bob rode home with a huge smile on his face.
Problems:
- Poor cranking speed, sometimes no cranking
- Gawdawful "CLACK" noise sometimes from inside the engine when starting
- Intermittent starting -- acts as if starter button isn't making contact, then fires randomly.
We first pulled the stator cover to investigate the starter clutch mechanism. This is a known weak spot -- the three small 8mm bolts holding the starter clutch to the back of the rotor sometimes stretch then back out, with potentially disastrous consequences. We thought the "CLACK" noise might be an early indicator of this problem.
All was found to be well with the starter clutch.
Since the stator cover was off and the gears were out of the way, we tested the starter motor with a known good battery and a set of small jumper cables. The starter spun powerfully, freely and quietly.
Mmkay, nice to eliminate two potentially expensive problems, but that's also two leading theories shot down...
After replacing the stator cover and gasket, we turned our attention to the rest of the electrical system.
With the key off, the battery read a healthy 12.8 volts. However, with the key on, the voltage immediately dropped below 12V, to around 11.5V, and dropped slowly from there.
When trying to crank the engine, voltage dropped well below 9V, and the engine barely turned before giving up altogether. Using the good battery and jumper cables as a booster, we saw an improvement in cranking speed, but it still wasn't good.
Around this time, we happened to discover that the clutch safety switch was intermittent, which explained that part of the issue. (Easy to bypass or replace with a $10 part)
Operating on the theory that there was some electrical drain and/or a bad connection, we then removed the headlight, tank, and airbox, and spent a pleasant hour or so cleaning all the connectors on the bike (with DeOxit spray, mostly), then reassembling with dielectric grease.
Several lightly corroded connections were found, and the main connector from the stator to the R/R (containing the +12V wire and the three stator wires) was found to have heavy corrosion. We disassembled this connector completely in order to scrub out every bit of the green gunk.
We also found and corrected a loose connection to the battery positive terminal.
Since we were in the neighborhood, we tested the stator with an ohmmeter, and it tested good: resistance between each pair was the same -- .7 ohm -- with no continuity to ground. (In other words, test stuff whenever the opportunity arises... information is always good, even though the stator doesn't directly affect starting.)
Upon testing, voltage drop with the key on was now acceptable (after all the abuse, the battery read 12.7V at rest, and 12.4V with key on). Cranking was now vigorous, and cranking voltage was around 12.0V.
Conclusions:
- The corroded connections, especially the main power connector from the R/R, were not allowing full power to the wiring harness.
- The loose battery connection seemed to be the primary cause of the weak starting and low-voltage issues
- We probably dodged a bullet big-time by catching the corroded stator connections.
- The starter safety switch is the same crappy low-rent design as the brake switch. I bypassed it on my bike years ago, and we coped on Bob's bike by simply jiggling the clutch lever a bit when the starter button didn't seem to work. This will eventually need to be fixed or bypassed for real, of course.
- Voltage at the ignition coils was still a tad low, although the bike ran fine -- the only electrical connections we couldn't easily clean today were the contacts in the ignition switch itself. We'll address this in the near future.
- The bike arrived at my house on a trailer, but Bob rode home with a huge smile on his face.
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