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1Back to top Go down    Eerie Electrical Gremlin 1988 k100 LT on Wed Apr 20, 2016 1:57 pm

KyleMB

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last year i bought this 1988 k100- 140,000 miles. kept up well and in great shape mechanically and otherwise... i started noticing some odd electrical gremlins such as the cooling fan would cycle on/off with the blinkers! i would randomly lose power around 3,500 RPM? (can't remember exact RPM) until i restarted the bike... of course i checked my connections, grounds, used some electrical lube etc...
last july i had a totaly melt down. on the interstate my tachometer stopped working and i had a battery light on. i tried restarting the bike on the fly and it wouldn't start... eventually i had to push the bike off and thats when smoke poured out from my right handlebar and under the gas tank. quickly shutting off the bike & towing it home i disassembled what was now a worthless piece of crap wiring harness that was totally fried.

after some intense googling and research i tracked down a gentleman and commissioned him to build a new loom for the bike. having replaced the wiring harness with this new one TODAY THE BIKE STARTED UP AND IT SOUNDS AMAZING. Here is a link if you'd like to hear it:

https://goo.gl/photos/2wV5LxRqN1NvUboy5

unfortunately i found some gremlins!
everything checked out except the blinkers, the hazard lights, and low beam would not work. i let the bike idle until the fan came on and then i tried toggling the high / low beam and i noticed the high beam was causing the fan to come on! toggle to low and the fan would turn off, toggle to high beam and the fan is back on!
what the hell is going on with this fan gremlin? all the electricals have been replaces: the entire harness, the fuse box and everything inside, the switches, etc!

i need some k100 guru support so i can get this thing back on the road before i miss this summer too!
thanks in advance.

-K



Last edited by KyleMB on Wed Apr 20, 2016 4:25 pm; edited 1 time in total

    

2Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Wed Apr 20, 2016 3:26 pm

Crazy Frog

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@KyleMB wrote:after heavily some intense googling and research i tracked down a gentleman and commissioned him to build a new loom for the bike.

The answer is very difficult because the loom is not an original and something may be wrong.
BUT......
All the gremlins could come from a simple cause.....
Bad ground and/or the starter!
This is hard to believe, but this is a known problem.
Remove your starter (only 2 screws) open it and check the brushes and collector.
Sometimes a simple cleanup will do the job.

CF


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1986 k75, 1985 K100rt, 1985 K100rt/EML sidecar.
    

3Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Wed Apr 20, 2016 8:38 pm

RicK G

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Did you have the heated grips on at the time it went up in smoke. There is a resistance wire in the harness that sometimes over heats and causes a meltdown.
It is possible the meltdown and problems you were having were unrelated.


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"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

4Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Wed Apr 20, 2016 10:16 pm

KyleMB

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Good news: blinkers, headlights (both high & low) and hazard lights all work!
Looks like the cable was loose under the blinker relay and that was it for the hazards too. i wasn't using the correct switch for the low beam.
so that just means turning the headlight ON was toggling the cooling fan somehow. maybe a bad relay? but how is the headlight interfering with the temp relay?


something else i noticed: when i kick the throttle fast the engine hesitates and nearly cuts out. ( https://goo.gl/photos/S7DpD1TpfGmDST3M7 ) not sure if it just needs to run or what.

my LT has never had heated grips. and yes im sure the meltdown problems were unrelated as that wire harness was the original, had been modified, and was starting to look a bit stiff... my new wiring harness on the other hand is looking great, BUT WHERE IS THAT GREMLIN?

also took apart the starter, cleaned the brushes. looks good.

    

5Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Thu Apr 21, 2016 3:21 am

Holister

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As far as I can see from the wiring schematics, the power for the fan (which is switched inside the temp controller) comes from the load shed relay along with the headlight power. If your h/lights are 'always-on" as they are here in Oz then this would indicate that the contacts for the fan inside the temp controller are stuck on and the fan spins whenever the power is on. Someone else may be able to give you some advice about pulling the controller apart to see if you can repair the contacts if that's the case but I'd also suggest if you can get a spare, try swapping the temp controller with a good one.

Another suggestion would be to check the temperature sensor.
A question for the Krew here.... Can resistance on the temp sensor for the controller be assessed in the same way as the sensor for the FICU? or being the one sensor with two outputs, does the measurement at the FICU relate also to what's being sent to the temp controller?
If the sensor is indicating hotter than normal, the temp controller may be switching the fan on from the get-go. Just a thought.

All this is assuming there's nothing wrong with the new wiring harness as CF points out above.

As for the poor throttle response. Most probably a mixture issue. Could be any number of problems. For anyone to help with that, more information would be needed.
Have your checked the air filter?
Have you replaced the fuel filter?
How well does it start?
What do the spark plugs look like? This tells a lot about what's happening with the fuel and ignition.
Poor throttle response is one thing but what's the response like higher up the power band? Does it pull well above 4k rpm?
Have the valve clearances been checked?

You could have an air leak in the air intake. This is very common. Crankcase breather, throttle body rubbers, oil filler cap o-ring, injector o-rings.

If the timing has been fiddled with, that could be out. That should not need touching generally.

Take your pick. You just need to work your way thru these till you get her running sweet. Just ask for help with any of this.
Cheers



Last edited by Kaptain Holister on Thu Apr 21, 2016 4:20 am; edited 1 time in total (Reason for editing : typo)


__________________________________________________
1988 K100RT VIN No. 0094680
1989 K100RT VIN No. 0097367 (naked)
1996 K1100RS VIN No. 0451808
Fuel: 95 Octane
Engine Oil:Nulon Full Synthetic 15W50
Gear Box Oil: Nulon Synthetic 75W90
    

6Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Thu Apr 21, 2016 9:05 am

Dai

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Time to own up: I built that loom - see http://www.k100-forum.com/t10428-comberjohn-s-ghost. The right-hand switch is European, so the lights aren't on permanently. It was well-tested here, so in theory there's nothing wrong with it. In theory. The only deviation from standard is that it has two separate relays fitted for the headlight; the power for the headlight now comes from the normally unused fuse 4. The wiring diagram is in the thread. At the end of the day, the only thing I couldn't test thoroughly was the temperature sensing relay so KH may have something there.


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

7Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 12:09 pm

KyleMB

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This will be the second time cleaning the starter for hopes that this is the issue for the gremlin. Again, when the radiator fan turns on and I activate the blinkers, the fan cycles on/of with the blinkers. I agitated this symptom the other day and the bike shut itself off. It wouldn't restart until I reconnected the battery.

Anyway, here are some detailed photos of the starter:

https://goo.gl/photos/QdsX4PNnMZieUvLk8

    

8Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 4:10 pm

Holister

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Those brushes look worn to me. Especially the one connected to the terminal. 6mm is the service limit.
As they wear down the spring pressure behind them decreases until electrical contact becomes intermitant.


__________________________________________________
1988 K100RT VIN No. 0094680
1989 K100RT VIN No. 0097367 (naked)
1996 K1100RS VIN No. 0451808
Fuel: 95 Octane
Engine Oil:Nulon Full Synthetic 15W50
Gear Box Oil: Nulon Synthetic 75W90
    

9Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 7:18 pm

Dai

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Confirms my thoughts...


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

10Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 8:01 pm

Two Wheels Better

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Carbon brush set rear, 12 41 1 459 567 is $15.48. Carbon brush set forward, 12 41 1 459 297 is $13.58 from US dealers, unless you can locate an auto electrician supplying them. It's a very common type of ND starter motor.


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1987 K100RS, '93 K11/K12 hybrid 'Big Block', '09 K1300GT, '07 K1200R, '04 R1150RT, '95 R100 Mystic, '77 R75/7.
Have we accomplished half of what we dreamt we would? There may still be time.
    

11Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 11:01 pm

Holister

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.... or you can buy the complete Starter Repair Kit bearing, o-rings and brush set.


__________________________________________________
1988 K100RT VIN No. 0094680
1989 K100RT VIN No. 0097367 (naked)
1996 K1100RS VIN No. 0451808
Fuel: 95 Octane
Engine Oil:Nulon Full Synthetic 15W50
Gear Box Oil: Nulon Synthetic 75W90
    

12Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Fri May 20, 2016 11:08 pm

KyleMB

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Holister (KH) wrote:.... or you can buy the complete Starter Repair Kit bearing, o-rings and brush set.
yea i just got that!

i will post results

    

13Back to top Go down    Re: Eerie Electrical Gremlin 1988 k100 LT on Mon May 23, 2016 4:38 pm

KyleMB

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i replaced the brushes and the gremlin still lives. check out this video of all the bugger the fan experiences. could it be the fan is going out? the temp relay? the load shed relay? any other relay?


https://goo.gl/photos/pmgo6BYnRYrsErn36


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1988 K100 LT
    

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