06-25-2012, 08:17 PM #1
Kawi ZXi1100 tachometer on a sl650?
I bought a ZXi tachometer here
It has 3 wires and my polaris sl650 requires a 3 wire connection.
Polaris wires are black (ground), yellow (stator rpms), orange (ignition)
Zxi wires are Black/white (ground?), Red/white (?), gray (ecu rpms signal)
Right now I have black to black/white, yellow to gray, and orange to red/white. The gauge goes straight to 6k rpm at about 1200rpm idle and will increase/decrease with throttle.
A tough question but any gurus have any answers?
06-25-2012, 11:00 PM #2
- Join Date
- Jul 2007
- near Toronto, Canada
The Polaris engines utilize the Yellow wire for double duty. First function is to control the battery charging.
The LR voltage regulator module manages the AC current flow to ground from the Yellow wire (yes, alternating current) to control the battery charge voltage on Red/Purple. The result is a funky half sine wave AC signal on the Yellow wire that changes frequency with engine RPM.
That brings us to the second use of the Yellow wire - to drive the RPM indicator (tachometer).
Going from memory, I think the Polaris stator produces 6 voltage 'pulses' on the Yellow wire per crank revolution. So at 600RPM the engine delivers 3600 pulses in one minute. The Polaris MFD takes those Yellow wire pulses, divides by 6 and displays the result as RPM.
It would appear your Kawi tachometer is expecting only one pulse per engine revolution, not six. So the Kawi reading is roughly six times higher than actual.
Since the ignition system in the Fuji engine (with the exception of the Pro 785) is wasted spark, even the CDI operates at three times the actual engine RPM. There is no electrical signal on the Fuji engine that pulses once per revolution, as best I can tell.
There are aftermarket tachometers that have an adjustable setting for exactly this purpose, to tell the tach how to divide the pulses to produce an accurate RPM reading.
06-26-2012, 10:41 AM #3
Great info! thank you
So I am actually idling around 1000rpm then. Now how do i divide that signal by 6?
06-26-2012, 12:05 PM #4
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