Neutral light question




bpcough

Registered
I have built a mini-dragster powered by a hayabusa. I had to completely change the wiring system because i use a motec ecu.
I need to add a neutral light on the dash to make it legal for the drags.
It seems to me that the neutral sensor is on the clutch side of the motor. There is a red, blue and black wire running out of the sensor.
Can anyone tell me how to wire up a neutral light?
thanks
Bryan
 

twotonevert

Member of P.E.A.
Moderator
Donating Member
Registered
Man, wish I knew, someone will chime in. Welcome to the oRg. :beerchug: I think that signal comes from the "gear position switch". Still looking. Maybe the black wire, someone confirm?
 

fiend

Formerly fiend44444
Donating Member
Registered
Welcome to the org.! I'm thinking the GPS to is where it would be.
 

bpcough

Registered
thanks guys. I put 12 volts to the red wire with the motor in neutral and tried
a test light on both the blue and black wire and got no light.
I am a bit puzzled. I wil post some pics as soon as i figure out how to.
Bryan
 

dadofthree

Seasoned Beef
Donating Member
Registered
B/W is negative, P to P on the ECU, Bl to Bl on ECU wiring diagrams 8-14 and 8-15 online manuals for 99-07.
 

omslaw

Michelle owns my Busa
Staff member
Administrator
Registered
When you release the clutch and it doesn't move...it's likely in neutral :poke:

Umm - Yeah, smithabusa would probably be able to tell you right off.

Take this with FWIW, though. I've never taken the GPS apart, but what I've read...I believe it's more or less a bunch of resistors. The 3 wires that you're referring to on the clutch side are the GPS... I bet one is ground, another is +5V DC and the 3rd is a 'sensor' wire. The ECU is reading the voltage off the sensor wire. Each gear has a specific resistor - 6.8K for 5th, 15K for 6th, etc. By reading the voltage on the sensor, the ECU knows what gear the bike is in. Now, all that said, I don't know what the value is for neutral...this is where smithabusa may be able to help.

My guess is that you would have to build something that will trigger at a certain voltage...

Or here's another thought, get a gear indicator, such as a GI Pro, Acumen, or even one that smithabusa builds... Then you would know all your gears as well as neutral. ;)
 



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