Author Topic: sudden shut down`  (Read 829 times)

Offline All6ofus

  • Motobrick Curious
  • Posts: 16
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sudden shut down`
« on: October 08, 2018, 06:34:42 PM »
I came across an issue while riding today.  I was cruising along at about 75mph and had a sudden complete no-run situation.  Is it possible for the side stand switch failure to cause this situation?  Also, is it possible for it to be an intermittent failure?

Just thinking about options.  I'm planning on checking/cleaning the ignition switch and four-pin connector tomorrow.  Too frustrated to mess with it today.

I have a new fuel pump, fuel filter, fuel pump relay, battery, ignition coils, plugs and wires as of 2k miles ago.  Swapping in a different ECU from a donor bike didn't resolve the issue (thankfully...?) 

It never sits for more than 2 days without riding and she was doing great until today.  I ride year round in Oregon and 60% of the time, there's rain involved.   
  • Portland, OR
  • '94 K1100 RS

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5766
Re: sudden shut down`
« Reply #1 on: October 08, 2018, 06:54:26 PM »
. . .  had a sudden complete no-run situation.   
Does that mean nothing worked—no starter, no headlights, no instruments, no sound of fuel pump priming, or that the engine would crank but not start?
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline billday

  • ^ SuperNatural Motobricker
  • Posts: 933
Re: sudden shut down`
« Reply #2 on: October 08, 2018, 10:14:58 PM »
A bad ground in the starter can cause a sudden shutdown. In my case it was the terminal post with a brush on one end that passes thru the starter body. It needs o-rings to insulate it from grounding on the starter.
  • New York State, USA 10977
  • 1985 K100

Offline The Mighty Gryphon

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  • Posts: 3966
Re: sudden shut down`
« Reply #3 on: October 08, 2018, 10:47:14 PM »
My K75RT ignition switch cuts out occasionally, shutting everything down.  Has done it now twice in the past two weeks.  Shutting off and turning it back on gets everything running again.  Looks like I will need to go in there when I get home.  Was in there 4 years, 30,000 miles ago.    The design of that switch does not impress me.

BTW, do you have a key fob or key chain on your ignition key?  The RT only tolerates naked keys.  It's almost impossible to keep the ignition on when the key has anything hanging off of it.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '92K100RS White, '94 K75S Dakar Yellow
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'94 K75S "Cheetos"
'91 K100RS "Moby Brick Too

Offline All6ofus

  • Motobrick Curious
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Re: sudden shut down`
« Reply #4 on: October 09, 2018, 01:04:50 AM »
Still have all electricity, starter cranks fine, but its not engaging the fuel pump.  Normally when I turn the key I can hear it prime the pump.  Nothing now, and no fuel delivery.  Just dry cranking.  I guess if the side stand switch went bad I wouldn't have any starter operation...  Fresh eyes tomorrow should help.  Thanks so far though!
  • Portland, OR
  • '94 K1100 RS

Offline All6ofus

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Re: sudden shut down`
« Reply #5 on: October 09, 2018, 01:11:21 AM »
No key fob or dangling garbage hanging.  Bare naked key in the ignition.  Ill take a good look at the ignition and starter and get back to y'all.
  • Portland, OR
  • '94 K1100 RS

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5766
Re: sudden shut down`
« Reply #6 on: October 09, 2018, 08:16:51 AM »
Ill take a good look at the ignition and starter and get back to y'all.
Fuse #6 is the fuel pump. Check the fuse.

According to my 1995 copy of the K1100 riders manual, the side stand switch will shut off the pump but still allow the starter to engage. Find the switch and jump its leads
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline The Mighty Gryphon

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  • Posts: 3966
Re: sudden shut down`
« Reply #7 on: October 09, 2018, 08:23:01 AM »
The connector for the side stand switch is on the right hand side of the frame, near the rear brake reservoir.

It could also be a bad fuel pump relay:

http://www.motobrick.com/index.php/topic,536.msg1309.html#msg1309
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '92K100RS White, '94 K75S Dakar Yellow
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'94 K75S "Cheetos"
'91 K100RS "Moby Brick Too

Online Martin

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Re: sudden shut down`
« Reply #8 on: October 09, 2018, 05:14:40 PM »
Also check the infamous 4 pin connector which supplies power to the fuel pump. It resides under the right hand side of the tank. You can try cleaning it with DeoxIT, however if faulty the best solution is to replace it with a 4 pin waterproof connector.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline CNRED

  • ^ Proficient Motobricker
  • Posts: 128
Re: sudden shut down`
« Reply #9 on: October 10, 2018, 07:42:44 AM »
I had the same symtoms on a '90 K75rt.
After alot of teeth gnashing and colorful language, three trips home on the trailer and the replacement of the fuel pump, filter, and fuel lines, my problem was with the fuel sender inside the tank.
Replace the sender and the bike ran beautifully from that point forward.  The sender was losing continuity to the fuel pump when the bike got hot, shuting off the pump. When it cooled down, community was restored and the bike would run until it got hot again. 
  • Scottsdale, AZ
  • 1990 K75rt, 1992GSPD

Offline stokester

  • ^ Proficient Motobricker
  • Posts: 411
Re: sudden shut down`
« Reply #10 on: October 10, 2018, 08:08:38 AM »
Also check the infamous 4 pin connector which supplies power to the fuel pump. It resides under the right hand side of the tank. You can try cleaning it with DeoxIT, however if faulty the best solution is to replace it with a 4 pin waterproof connector.
Regards Martin.
That would be my first check.
  • Yorktown, Virginia
  • '94 K75S - '93 K75S - '91 R100RT - '78 R100S

Offline All6ofus

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  • Posts: 16
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Re: sudden shut down`
« Reply #11 on: October 12, 2018, 04:40:56 PM »
After checking the 4 pin connector, ignition, cut off switch, and side stand cut off, everything checked out.  Finally I decided to pull the pump and bench test it.  Turns out the negative terminal was loose causing intermittent failure.  Ugh.  The intermittent issues always get overlooked when you're frustrated.  Lesson learned...take a breath, slow down, and double check everything. 

Feeling confident that the pump itself is the issue. 

Thanks for all the input though folks.  I'll get another waterproof connector and get a better ground on the starter so this sort of thing doesn't happen again. 
  • Portland, OR
  • '94 K1100 RS

Offline pinhead

  • ^ Motobrick Curious
  • Posts: 74
Re: sudden shut down`
« Reply #12 on: October 18, 2018, 05:51:56 PM »
I don't know if this is applicable but I will share.  I had severe corrosion on my kill switch.  The strangest thing was sometimes, the bike would start up as soon as I turned the ignition on.  No touching of starter button needed.   I used to think it was one of those "advanced design" features of the K bike (its a 1985). When I finally got around to disassembling the kill switch I found a shitload of corrosion all over (the bike was stored outside before I owned it).  Cleaned it all up and it didn't do that anymore.  Strange.........
  • sacramento, ca
  • 1985 RT 100

Offline johnny

  • TrailBrakingThrottleWhacker
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  • Whacking...n...Chopping Sliding...n...High Siding
Re: sudden shut down`
« Reply #13 on: October 18, 2018, 06:38:32 PM »
greetings...

everyday you ride a motobrick you gotts to work the switches on and off and on and off several times including hi low ho low beam flash to pass and includes turning the key full lock cw and ccw... its a simple method the keep them in good shape...

also getts a contact ring on that sidestand switch...

j o

  • i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin...
:usa#1

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