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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Wirelic on August 17, 2020, 10:00:10 AM

Title: Dying K75
Post by: Wirelic 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
Title: Re: Dying K75
Post by: Laitch 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.


Title: Re: Dying K75
Post by: Chaos 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
Title: Re: Dying K75
Post by: The Mighty Gryphon 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.
Title: Re: Dying K75
Post by: Wirelic 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.
Title: Re: Dying K75
Post by: volador on August 18, 2020, 12:52:42 PM
add a litre of Kerosene or Diesel a few tank fills flush system
Title: Re: Dying K75
Post by: Laitch 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.
Title: Re: Dying K75
Post by: volador 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?
Title: Re: Dying K75
Post by: Laitch 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.
Title: Re: Dying K75
Post by: K1300S 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.
Title: Re: Dying K75
Post by: Wirelic 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.