BMW K bikes (Bricks)

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1Back to top Go down   Disabling ignition spark. Empty Disabling ignition spark. on Fri Aug 09, 2013 5:25 pm

weez

weez
active member
active member
I'd like to safely check the injector spray patterns on my '87 K75 and NOT have a fire (like I did last year when a couple injectors popped out of the rail, gas got sucked into the injector ports and ignited the left side of the bike!) and also not damage any ignition electronics. Is anyone aware of an easy method with no danger of either? Is taking the secondary coil connections off OK with the ignition control unit?


__________________________________________________
1987 K75T 326K aka Uncle Fester.
2000 KLR 685
2000 KLR 650
1997 ST1100
2000 DRZ400E
    

2Back to top Go down   Disabling ignition spark. Empty disconnect on Fri Aug 09, 2013 9:42 pm

ibjman

ibjman
Life time member
Life time member
disconnect the tiny small wires from the ign. coils and put a bit of tape around the ends to insure they can arch to ground.

With no primary power the coil can't spark.

regards, Ibj....

    

3Back to top Go down   Disabling ignition spark. Empty Re: Disabling ignition spark. on Sat Aug 10, 2013 5:37 am

weez

weez
active member
active member
Many thanks for the reply. I'm taking this to indicate there's no risk of damaging ICU? For some reason I have it in my head you're not supposed crank engine without plugs grounded because it can damage "something" but can't remember what or even if this is correct info.


__________________________________________________
1987 K75T 326K aka Uncle Fester.
2000 KLR 685
2000 KLR 650
1997 ST1100
2000 DRZ400E
    

4Back to top Go down   Disabling ignition spark. Empty Re: Disabling ignition spark. on Sat Aug 10, 2013 7:53 am

RicK G

RicK G
VIP
VIP
That is correct that you can damage the ignition module if you dont ground the plugs but by disconnectig the coils you isolate the ICU from the source of the damage.
Withiut the plugs grounded you can induce very high voltages into the primary windings of the coils which in turn will fry the final switching transistors in the ICU, but as ibj said make sure the wires are insulated from shorting to the frame or engine as the high current draw can be just as dangerous.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


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

5Back to top Go down   Disabling ignition spark. Empty Re: Disabling ignition spark. on Sat Aug 10, 2013 8:54 am

weez

weez
active member
active member
@RicK G wrote: by disconnectig the coils you isolate the ICU from the source of the damage.
Thanks for explanation Rick. This is exactly what I was looking for.

For the spray test I'll use extreme caution this time and shrink tube the connectors/zip tie well away from any possible arcing paths.

For any others who ever do this test please take heed from my bad experience:  when you hit the start, fuel pump pressure can instantly pop one or more of the injectors out of the fuel rail and spray the side of the bike and YOU with a large amount of gasoline from the fuel rail. Then ANY source of ignition is all it takes. I was extremely lucky I didn't get sprayed and that I had a dry chem extinguisher. Without it I doubt I could've put this out and I likely would've lost my house when this happened last winter.


__________________________________________________
1987 K75T 326K aka Uncle Fester.
2000 KLR 685
2000 KLR 650
1997 ST1100
2000 DRZ400E
    

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