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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: Chicken Creek Customs on May 27, 2025, 09:57:44 PM
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Hey all,
New to the group and hoping someone can help clear a couple things up:
-I've converted a K75C to a GSX front end and plan to use the GSX controllers.
-The starter works fine.
-The bike no longer delivers a spark, so I'm wondering if the kill signal to the ECU is still being sent somehow due to the GSX wiring alignment with the K75 harness
-I've tried to follow the diagrams I've seen here for 100s, but I can't make out the wire colors due to low resolution of the images
I've attached the Control wiring (GSX) and the plug I'm converting (K75). Any help around this would be appreciated. Items like the Hall Sensor, plugs and harness have been replaced, so I'm thinking its finalized wiring that may be telling it not to spark.
Thanks!
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Power to the kill switch is GRN.
Power out from the kill switch is GRN/YEL.
Lots of wiring diagrams: https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/kwiring/kwiring.htm
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Have you used anything other that the complete original wiring from the k?
No spark -assuming spark plugs- can have many causes in this matter. So take us along the ride with all the modifications done, disconnects, reconnects, relays, fuses.
I do believe there was another forum user who went into gsxr(r) Controls and came to the conclusion that the killswitch works differently. As in, if you were to connect the wires one on one the killswitch from the gsx is "inverted" meaning using the off position sends the killswitch activated signal to the k and vice versa.
The K breaks the signal as in removing (if i recall correctly) ground from the circuit and the gsx model create a circuit to kill, sending a kill signal.
This could be fixed by using a relay.
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In addition, you can not re-route the cables on the control to invert the signal because the difference is still a circuit made or broken.
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Power to the kill switch is GRN.
Power out from the kill switch is GRN/YEL.
Lots of wiring diagrams: https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/kwiring/kwiring.htm
These have been very helpful in understanding the K-bike. The challenge is the new diagrams outlining the connection of Suzuki controls to a K harness.
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Have you used anything other that the complete original wiring from the k?
No spark -assuming spark plugs- can have many causes in this matter. So take us along the ride with all the modifications done, disconnects, reconnects, relays, fuses.
I do believe there was another forum user who went into gsxr(r) Controls and came to the conclusion that the killswitch works differently. As in, if you were to connect the wires one on one the killswitch from the gsx is "inverted" meaning using the off position sends the killswitch activated signal to the k and vice versa.
The K breaks the signal as in removing (if i recall correctly) ground from the circuit and the gsx model create a circuit to kill, sending a kill signal.
This could be fixed by using a relay.
This is where I am. The image I believe is correct to use is the attached. It shows only three wires used from a Suzuki to the K harness. The bit to the left (replacing the signal relay) has been done. But I can't determine the colors from the Suzuki or to the K, as noted in the drawings. When you try to get them large enough to read, the colors aren't understandable.
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In addition, With the key in the on position, I'm seeing power to pin 10, which should be the kill switch signal. I would think that the kill switch wouldn't allow the engine to turn over, but it does, and injection works, all lights work, signals work, hazzerd works, speedo lights up, etc. Also thinking it should NOT send signal to the ECU, but I'm not a BMW bike guy and continually find interesting approaches to the way this bike is designed. I've spent the better part of 40 years on Japanese bikes.
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No spark could also just be a poorly connected wiring harness to the ecu. You wouldnt be the first to not connect it correct.
Also, try starting with the killswitch turned both on and off (after checking if the wiring loom being plugged into the ecu fully)
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ECU is tight, and I've tried kill both ways. Any ideas of the correct colors for the image I dropped in? They're indicating a three wire jump, but can't tell which actual colors are used on the K harness in the image.
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I've circled the colors I can't determine here.
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Does anyone know if you can just bypass the kill? Or does the ECU need a signal?