6) – HARLEYS” PURPLE WIRE TO RPM GAUGE OR NEGATIVE COIL: Route the purple wire to 1 of 4 signals on Harley’s depending on the year model:
Harley’s Made Before 2003 – You can attach the purple wire to the negative side of coil crimp on the spade connector. (not the spark plug wire) If you are not sure which is the negative lead, try one, if incorrect no damage will occur. When testing, if unit fails to operate simultaneously, simply move the wire to the other coil lead.
Alternately this can be connected to a Hot Pink wire the tachometer signal is best. This hot pink wire covered with a black boot about 1” long under the dash on the tank or behind the headlight or in a harness under the seat.
Harley’s Made in 2003 to 2010 electronic ignition- have a blue wire with an orange stripe coming off the coil.
Harley’s Made in 2011 and onwards: Connect the purple wire to the gray wire with blue stripe. These wires runs under the seat on the right side of the battery in one of the harnesses connected to the ECM; use the quick splice connector on the signal wire.
Harley Davidson has yellow/green for common positive, blue/orange for the front cylinder, yellow /blue for the rear cylinder.
6A) – “METRIC/FOREIGN” PURPLE WIRE TO RPM GAUGE OR NEGATIVE COIL: Best way is the tach wire harness near steering fork. “If in despair, check with your local dealer to find out which color wire is for tach and where it can be found.” Most motorcycles will have two wires going to each of the two or four coils. Each coil will share one common color wire and will have one different color wire. Or the common color is positive, and the uncommon colors are negative. You want the negative wire that’s the uncommon color.
Yamaha has a red/black wire on both coils- that is positive. The other wire is orange or gray- that is the negative side.
Honda is black/white for positive, blue/yellow and yellow/blue for negative.
Suzuki RPM wire is yellow with blue stripe or has orange/white on both coils as positive, and white or black/yellow as negative.
Kawasaki has red/green for common positive, black or black/green for the negative side. Stick coils are on top of the spark plugs.
For some foreign bikes, it may be easier to splice in to the coil wire.