Author Topic: Dying K75  (Read 2564 times)

Offline Wirelic

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Dying K75
« on: August 17, 2020, 10:00:10 AM »
Need some help.  I just got an 86 K75.  It runs ok if I keep driving it, but if I stop at a stop sign, it dies.  As long as I ride at speed, it runs fine.  Stooping the bike and it dies.  Any ideas or suggestions?
Thank you very much for helping
  • Green Bay, WI
  • 88 K75, 77 Bonneville

Offline Laitch

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Re: Dying K75
« Reply #1 on: August 17, 2020, 10:37:04 AM »
How many miles on the odometer? Have you looked into the empty fuel tank to determine its condition? If you don't know the age of the fuel filter, replace it immediately. Check on the condition and tightness of the fuel tank hoses and their connections.
Report back.


  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Chaos

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Re: Dying K75
« Reply #2 on: August 17, 2020, 10:45:51 AM »
Fresh gas, run some Techtron, check the crankcase vent hose for cracks, (back left side of engine) what Laitch said
  • 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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Offline The Mighty Gryphon

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Re: Dying K75
« Reply #3 on: August 17, 2020, 12:03:08 PM »
+1 on the crankcase vent hose.  Also check the rubber caps on the throttle body balancer ports.  Make sure they are all there and none of them are cracked.

When was the last tune up with valve clearance check and throttle balance done?

Keep your fingers crossed that the throttle body bushings aren't cracked and need replacing.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

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 Wirelic

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  • Posts: 21
Re: Dying K75
« Reply #4 on: August 18, 2020, 11:56:33 AM »
Thanks very much, guys.  I’ll check on those suggestions.  It might take awhile, though, as I’m quite busy right now.
  • Green Bay, WI
  • 88 K75, 77 Bonneville

Offline volador

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Re: Dying K75
« Reply #5 on: August 18, 2020, 12:52:42 PM »
add a litre of Kerosene or Diesel a few tank fills flush system
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline Laitch

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Re: Dying K75
« Reply #6 on: August 18, 2020, 03:19:54 PM »
Diluting gasoline with ~5% kerosene or diesel fuel seems pointless and repeated use in ratios of that magnitude could cause carbonification and power loss in a Brick.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline volador

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Re: Dying K75
« Reply #7 on: August 19, 2020, 12:15:28 AM »
Diluting gasoline with ~5% kerosene or diesel fuel seems pointless and repeated use in ratios of that magnitude could cause carbonification and power loss in a Brick.

What's the point of running Techtron?
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline Laitch

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Re: Dying K75
« Reply #8 on: August 19, 2020, 11:32:42 AM »
The point of using Techron is to take advantage of lubricants and solvents contained in its proprietary formula to reduce deposits throughout the fuel system. If the idea is held that Techron contains no effective proprietary formula and only consists of repackaged kerosene, diesel fuel, or Stoddard solvent, there is no reason to use it; however, a 10fl.oz. container of Techron amounts to only slightly more than 1% of a 22L fuel tank's contents.

Gasoline combusts in mist droplets but kerosene combusts in vapor so should be preheated for complete combustion. Until the chamber is hot enough for kerosene to vaporize, it will deposit carbon in the chamber and elsewhere which will interfere with performance if enough of it accumulates from cold starting. A proportion of 5% kerosene or greater in fuel contents will likely cause accumulation of carbon.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline K1300S

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Re: Dying K75
« Reply #9 on: August 19, 2020, 01:09:48 PM »
when was the last time the bike got a complete tune up?  if you don't know the answer or it has been a few years, it is time.
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline Wirelic

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Re: Dying K75
« Reply #10 on: August 19, 2020, 04:50:39 PM »
I don’t know when it last got a tune up.  It’s new to me.  I’ll sort thru everyone’s suggestions and let you know what I find out or what turns up.   Sounds like it’s overdue for a service.
  • Green Bay, WI
  • 88 K75, 77 Bonneville

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