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Tacho question
Lightning - 4/2/10 at 12:06 PM

Car nearing completion, I have a small problem of the tacho redaing twice the true reading. This is also with true with the Speedwell. I guess its because its getting the pulse from the coil pack which has a waste spark. Where should I get the pulse from??? ZZR1200 BTW
Many thanks


blakep82 - 4/2/10 at 12:30 PM

what ignition system is it?


Lightning - 4/2/10 at 12:38 PM

The Kawasaki system from the bike. Its on zzr1100 carbs BTW


matt_gsxr - 4/2/10 at 12:42 PM

I guess you have a wasted spark ignition, hence the double reading.

Can you change the setting to make it 2-stroke. That fires each cycle and then it will be fine again.

I don't know of an easy way to halve the pulses (I guess you could build some kind of flip-flop circuit which would halve the pulse rate). The Dyna 2000 ignition units have 2 different outputs for tachos (one every cycle and one with 2 per cycle). Does your CDI not have an appropriate output, sometimes they do.

Matt


BenB - 4/2/10 at 12:43 PM

Yes you could just put a flip-flop circuit in it series. Would cost all of a pound and take about 30 min to make slowly.


Brommers - 4/2/10 at 01:21 PM

The tacho output from the ECU will usually give one pulse per engine revolution (it does on all the bike engines I've played with). Looks like it's a light blue wire coming from pin 23 on the ECU according to the ZX12R wiring diagram I've found here.


matt_gsxr - 5/2/10 at 11:40 PM

Brommers,

Not sure this is the case with Suzuki engines.

Just noticed that you have updated your pages. Nice one. I got a bit bored of looking at those data-log outputs from September.



Matt