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K100-forum.com » Technical, repair and troubleshooting » Electrical » Another K75 Gremlin

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1Back to top Go down   Another K75 Gremlin Empty Another K75 Gremlin Sat Feb 06, 2021 1:35 am

jjefferies

jjefferies
Life time member
Life time member
This past Wednesday I dropped by a friend's shop. Got ready to leave, helmet on, earplugs in, I get on my K75 and start it up. Makes an odd whirring sound starting but it does start and with helmet and ear plugs in I don't hear anything too unusual. I hit the freeway and notice that my turn signal indicators aren't indicating, and hi beam indicator isn't indicating either. Choice is to turn back to the shop or continue home. I opt for home. Halfway there the low fuel light comes on. Fine should be able to make it. Bike is doing the usual surging like when the fuel is low and rapid acceleration/stopping causes the gas to roll around in the tank. I get home put it up on the center stand and leave it running. As suspected there were no headlights or running lights, brake light, or turn signals. I turn off the main power switch. Bike keeps running. Sounds like it's dieseling. Uh Oh!. Ok, I now do something stupid and forget about the KILL switch. Just not used to thinking of it. It was like the machine was possessed and refused to stop. So I pop off the fuse cover and remove all the fuses. Bike's still running with weird sound like it's dieseling. I hop up on it, put it in gear, put on the rear brake and let out on the clutch slowly stopping it. Now I think about the kill switch and hit it. Bike is stopped. Wheww! Back on center stand, replace all the fuses, add 1/2 gallon of fuel, turn it on and start it. Everything is normal. Well the clock is reset to 0 as I had pulled its fuse. Test the kill switch. It stops everything correctly. Now I don't know whether I trust this machine. Possessed motorcycles are the worst.  Suggestion is that I give it half a tank and go ride a couple hundred miles to see it it repeats the behavior. Not sure I want to get that far from home. Any suggestions or helpful comments about what to look for?

It had been a totally weird day. Started with the throtle advance/choke light staying on. Turned out the cable had been pinched. Such things I can deal with. And there were other oddities. But demons possessing my bike ....

    

2Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Sat Feb 06, 2021 1:58 am

MartinW

MartinW
Life time member
Life time member
Dirty starter motor brushes cause all sorts of weird problems. You can sometimes get a temporary fix by back spinning the starter motor. With the engine off roll the bike backwards in 5th gear and pop the clutch do this a couple of times. However it is best to remove the starter and pull it apart and clean it also check the length of the starter brushes and replace if necessary.
Regards Martin.


__________________________________________________
1992 K75s
    

3Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Sat Feb 06, 2021 4:02 am

Suzi Q

Suzi Q
Life time member
Life time member
Sounds like it might be your starter relay sticking in. Happened to me once, and it's apparently not uncommon for the k. Something to do with a low battery current allowing the relay contacts to oscillate and weld themselves together. They can unstick - hence the problem seems to cure itself.

The whirring sound on starting might have been the starter continuing to turn. It'll do it during your journey and it wouldn't have been under load whilst the engine was running - the starter freewheel allows that.
Once you try and stop the bike it'll just keep on turning.
Pulling fuses will make no difference, because there's no fuse in the starter high current circuit.
Full beam, indicators won't work because the LS relay will still be de-energised - its coil negative will be at the 12v still on the starter motor terminal.
Hitting the starter relay with a toffee hammer works. A bit.


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

4Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Sat Feb 06, 2021 7:26 am

Dai

Dai
Life time member
Life time member
Turns it into toffee, does it Chris?


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

5Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Sat Feb 06, 2021 7:27 am

Dai

Dai
Life time member
Life time member
But yes, I'm with the 'suspect the starter relay/motor' guys. It's easy enough to pop the top off the starter relay and inspect the contacts.


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

6Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Sat Feb 06, 2021 1:51 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Yep, starter brushes and dirty commutator. As long as you have things apart and cleaning stuff, if you haven't done it already, pull the ignition switch and clean it as well. That is another source of strange electrical happenings.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

7Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Mon Feb 08, 2021 12:22 am

jjefferies

jjefferies
Life time member
Life time member
Thanks for the suggestions guys. I'll leave Silver alone until I can pull the starter and clean it. Which might take a while as I've got a new to me, 1986 K100 project bike. It's been sitting in an apt. garage for the past 10 years and I just got it home and parts are spread about. So will ride the Red K75 for the moment.

J.

    

8Back to top Go down   Another K75 Gremlin Empty Re: Another K75 Gremlin Mon Feb 08, 2021 6:46 am

92KK 84WW Olaf

avatar
Life time member
Life time member
Maybe pull the starter motor out of the project bike and refurb it and drop it on. And take the relay too.

It does so very sound like starter/starter relay issue.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 49,200 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

Bruce Petterson

Bruce Petterson
Silver member
Silver member
jjefferies wrote:This past Wednesday I dropped by a friend's shop. Got ready to leave, helmet on, earplugs in, I get on my K75 and start it up. Makes an odd whirring sound starting but it does start and with helmet and ear plugs in I don't hear anything too unusual. I hit the freeway and notice that my turn signal indicators aren't indicating, and hi beam indicator isn't indicating either. Choice is to turn back to the shop or continue home. I opt for home. Halfway there the low fuel light comes on. Fine should be able to make it. Bike is doing the usual surging like when the fuel is low and rapid acceleration/stopping causes the gas to roll around in the tank. I get home put it up on the center stand and leave it running. As suspected there were no headlights or running lights, brake light, or turn signals. I turn off the main power switch. Bike keeps running. Sounds like it's dieseling. Uh Oh!. Ok, I now do something stupid and forget about the KILL switch. Just not used to thinking of it. It was like the machine was possessed and refused to stop. So I pop off the fuse cover and remove all the fuses. Bike's still running with weird sound like it's dieseling. I hop up on it, put it in gear, put on the rear brake and let out on the clutch slowly stopping it. Now I think about the kill switch and hit it. Bike is stopped. Wheww! Back on center stand, replace all the fuses, add 1/2 gallon of fuel, turn it on and start it. Everything is normal. Well the clock is reset to 0 as I had pulled its fuse. Test the kill switch. It stops everything correctly. Now I don't know whether I trust this machine. Possessed motorcycles are the worst.  Suggestion is that I give it half a tank and go ride a couple hundred miles to see it it repeats the behavior. Not sure I want to get that far from home. Any suggestions or helpful comments about what to look for?

It had been a totally weird day. Started with the throtle advance/choke light staying on. Turned out the cable had been pinched. Such things I can deal with. And there were other oddities. But demons possessing my bike ....

    

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