Starter engages while at high RPMs

Romi3 · Jan 4, 2016

Happy new year everyone!

Was hoping someone out there would be able to help me out. My 75 MKIII starter has been working perfectly for the past few months as I have been mostly communing to work and going on short little rides. Well yesterday I took a ride up to Pasadena to meet a buddy and when I got on the Freeway and got the bike up to 4,500 RMPs I heard a noise but as soon as I backed off the throttle the noise stopped. It happened twice on the way up there and when I did arrive and tried starting my bike the solenoid just clicked. To avoid any major issues, I took a 10mm and disconnected the heavy gauge wire to the starter and taped it up. On the way home I was jamming on the freeway at high RPMs and it didn’t do it again. Anything like this happen to any of you?

Any help of feed back is appreciated.

Thank you,

Nater_Potater · Jan 4, 2016

Romi3 said:
Happy new year everyone!

Was hoping someone out there would be able to help me out. My 75 MKIII starter has been working perfectly for the past few months as I have been mostly communing to work and going on short little rides. Well yesterday I took a ride up to Pasadena to meet a buddy and when I got on the Freeway and got the bike up to 4,500 RMPs I heard a noise but as soon as I backed off the throttle the noise stopped. It happened twice on the way up there and when I did arrive and tried starting my bike the solenoid just clicked. To avoid any major issues, I took a 10mm and disconnected the heavy gauge wire to the starter and taped it up. On the way home I was jamming on the freeway at high RPMs and it didn’t do it again. Anything like this happen to any of you?

Any help of feed back is appreciated.

Thank you,

Yikes! A starter engaging at that rpm could cause some serious damage to the primary drive, not to mention the end of the crankshaft. Since it stopped once disconnecting the cable, I'd be inclined to believe it has something to do with vibration getting after the starter's electrical circuit, most notably the green button and/or associated wiring to same. Hook a test light to the wire that would normally be connected to the starter, and run the engine up to 4500rpm while sitting in the driveway. If you note anything, do the same at the small lead at the solenoid that comes from the green button. I suggest a test light as that is easier to discern than your typical DMM in a dynamic sense.

Nathan

Romi3 · Jan 4, 2016

Good input. I initially thought it was the electrical but then I got to thinking that the crank may have been spinning so fast that it engaged the sprag clutch. The last time it happened, I was on a side street and turned the key off which stopped it, then I turned the key back on and bump started it while I was still going about 45MPH. Again, after I disconnected the main wire on the starter, it didn’t do it again, which makes me think it would be electrical.

I’ll try your test tomorrow when I get a minute. Thanks again!

Jerry Doe · Jan 4, 2016

Yes thats scary. My problem during the holidays was that i accidentally pressed the start button while it was running. It was at idle, but destroyed the sprag. It sounds like the solenoid was firing for some reason, but if it were me i would look in the primary at he sprag to make sure its ok as well. Even if it was originally an electrical issue, it could have damaged the sprag.

Starter engages while at high RPMs

Romi3

Nater_Potater

Romi3

Jerry Doe

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