Author Topic: 1987 K75 keeps starting  (Read 5138 times)

Offline brianhinton

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1987 K75 keeps starting
« on: May 06, 2017, 08:23:14 PM »
So.....I decided to change the rear shock on the K75 finally. After I was done, I really wanted to take a test ride. I hit the starter and it coughed then kept trying to start as I switched off the ignition. This has happened before so starter relay had fouled up. I ordered a new one from euromoto and it arrived today. I installed a new Odyssey PC 680 and the the relay. Battery was at 12.75 volts. Got it all buttoned up and hit the starter, it cranked right up. I let it idle for a minute and then decided to do something else so I switched it off.....and when I did, it kept starting!!! Dang! Does this mean maybe I got a faulty relay or can you gurus point me in another direction?


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  • Wetumpka, AL

Offline Martin

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Re: 1987 K75 keeps starting
« Reply #1 on: May 06, 2017, 10:18:22 PM »

Try Deoxit on your starter button it could be jamming on, you might have to pull it apart.
regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline The Mighty Gryphon

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Re: 1987 K75 keeps starting
« Reply #2 on: May 07, 2017, 11:04:22 AM »
There is a plastic connector on the side of the start relay.  Does the starter stop running when you pull the connector off? 

If it stops, the problem is in the start button or the wiring from it to the relay.

If it keeps running, the problem is in the relay or the starter wiring.

I agree with Martin, the problem is probably in the start button, but before you start working on it, pull the connector to make sure.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
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Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline kioolt

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Re: 1987 K75 keeps starting
« Reply #3 on: May 07, 2017, 12:02:34 PM »
If it's still cranking with the ignition switch off it's not the starter button.  The ignition switch kills power to the starter button so it wouldn't matter if the button was stuck.
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1991 K100LT 128,700 miles,1982 R100RT 106,900 miles
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Offline brianhinton

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Re: 1987 K75 keeps starting
« Reply #4 on: May 07, 2017, 01:50:00 PM »
Yeah, it's not the switch. Back in the relay, just sucks that it's right out of the box and faulty....


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  • Wetumpka, AL

Offline Filmcamera

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Re: 1987 K75 keeps starting
« Reply #5 on: May 07, 2017, 02:03:18 PM »
Hmm that seems unlikely to me, is there anything that might cause a relay to fail like that? Or maybe another cause other than the relay.  Two relays on the trot - dunno just feels wrong somehow?
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Offline Martin

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Re: 1987 K75 keeps starting
« Reply #6 on: May 07, 2017, 02:46:10 PM »

If it's not the starter button, it comes back to the relay. The relay normally jams on due to low battery voltage. I would charge your battery then pull apart your original relay and clean up the points. Once you have done this replace your new relay with your old one and see what happens. Warning I have blown out the side of a battery, caused by a relay sticking I now have a battery isolator switch wired into the battery earth lead.
Regards Martin.

  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Chaos

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Re: 1987 K75 keeps starting
« Reply #7 on: May 07, 2017, 03:27:51 PM »
did you charge the battery before installing it?
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline brianhinton

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Re: 1987 K75 keeps starting
« Reply #8 on: May 07, 2017, 09:47:50 PM »
Fully charged battery, one good whack on the new relay and life is good


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Offline Martin

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Re: 1987 K75 keeps starting
« Reply #9 on: May 07, 2017, 10:25:19 PM »

 :2thumbup: The points stuck, clean up your old relay as a spare. And possibly have a look at fitting an isolator switch.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Chaos

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Re: 1987 K75 keeps starting
« Reply #10 on: May 07, 2017, 10:43:04 PM »
a well placed whack can work wonders!
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

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