rev counter

[ccrxxx]

hi, i have a gs550 ,i bought an aftermarket rev counter ,people say i wire it to the coil is this correct???????? thanks

[tone]

Yep it picks up from the coil pulses but may read at twice engine revs or half revs depending on what it was originaly made for

give it a go & see what happens :-D

[ccrxxx]

thanks, it has two wires so asume one to the coil and the other is for the light?

[SPARKSS]

thanks, it has two wires so asume one to the coil and the other is for the light?

I wouldn't "assume" anything but would research or look at case/terminal markings or disassemble to find out for sure. I'll guess that you're looking at some sort of electronic tachometer. Ones made for spark ignition engines often have a coil wire (goes to the switched side of the coil), another may go to power source for internal circuitry or merely lighting. Case may be ground.

What it will read is another issue.....because it's simple to connect, I'd try it first and verify with either a mechanical or phototach.

Electronic tachs are made with a variety of input circuitry, expecting to see various numbers (and amplitudes!) of signal which are USUALLY averaged to provide a meter deflection or digital representation. Very rarely are they actually frequency counters. A tach made for a 4 cylinder 4 stroke, distributorless ignition system, using double ended coils (much like your bike) would be a good choice. Picking one coil of your bike and looking at it's switched primary lead will see 1 pulse per crankshaft revolution. For comparison, a tach made to look at the pulses of a 4 cylinder 4 stroke distributor (1 coil) automotive engine is expecting to see 4 pulses per 2 crankshaft revolutions or 2/crank rev so installing one on your bike (assuming similar dwell) may read twice as high. A similar tach made for more cylinders would read correspondingly higher. A compounding problem is that automotive tachs may not typically read high enough, even with the correct logic, for some bike uses! A 2 stroke spark ignition tach which looks at one cylinder would be worth looking at as it expects an ignition event/crank revolution (same as your bike with it's double ended coil feeding 2 cylinders) AND the usual operating range is closer to what your original tach. For example - I've recalibrated the scale of a 4 cylinder tach as described above, to use on an 8 cylinder engine such that it then reads half it's original reading for a much better normal-driving range on a truck (0-8000 range becomes 0-4000 rpm full scale).

Occasionally, electronic tachs have 2/4 cycle and multi-cylinder switches and even calibration pots that can be customized for specific uses. Once again look it over closely or research.

There are other electronic tachs out there made, usually, for diesel service which expect to see an AC input from an inductive pickup coil off the crankshaft or even a special alternator output terminal. These are calibrated to lower rpm operation which may help identify them.

Hope this sheds a little light on the subject to get you started.

[ccrxxx]

nice one, ill have to study your reply.cheers for the help.