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85 K100 LT Dies and funny starter action.

goodwrench

Hand crafted
This is a weird one. Working on a friends bike and it died on him several times and he says the dash lights were off when this happened and then would turn the switch off and restart. When I got it I noticed that sometimes when you held the starter button on it would engage the starter for a split second then disengage and in a cycle of every 1 second or so it would engage and disengage. I could feel the starter relay with my hand engaging and disengaging. I put a test light on it and it was pulsing. One time it engaged and wouldn't stop cranking even with the emergency stop switch off, so I had to disconnect the battery. The fuel pump runs when I hit the starter. I don't have a manual. I checked pin one on the ecm for ground and it was good. Battery seems strong. fuses are good. Any ideas?
Jerry
 
Check battery voltage during cranking.

Sounds like a low battery.

Other possibilities include; bad battery cable connections, dirty contacts inside ignition switch, dirty commutator in starter.



:dance:dance:dance
 
I think I may have a fix. Took it for a ride and at the turnaround it died and the starter wouldn't engage and the dash lights were on. Started wondering if they run the starter relay off the fuel pump relay. When I got back to the shop I turned it off and tried to restart and no crank. While I had my finger on the starter button I tapped on the fuel pump relay and she started. So I got a relay ordered as they are configured different than most little Bosch relays.:dance
 
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