Bike Tachometer for Onan

[Theroundhousernr 589]

Ok I want to add a tachometer to my 416H Onan snow machine. I found these dual fire ignition tachometers made for twin cylinder bikes at an affordable price on eBAY and Amazon.

 

   Why you may ask, that I want a tachometer for my garden tractor? Cuz I am a big kid and like seeing things spin around and move lol. You know ... oooooooo , aaaaahhhhhh. So now that we got that out of the way.

 

 

  The wiring diagram with the tach shows a setup with a coil and distributor. The signal wire from the tach goes to the negative side of the coil. What doesn't make sense is why they show a coil and distributor. I thought a dual fire ignition throws spark out of a dual wire coil at the same time reguardless of compression stroke or not. SO NO distributor right? Just points/or ignition module and condenser. No distributor..... I think. That's how the onans are . NO idea about a Harley.

 

  So is this just a silly kindergarten drawing or am I missing something.

 

  Second , the onan coil is wired a little different with the positive side going to the condenser. Is this where I would hook up the signal wire on an onan?

 

   Thanks guys Kyle

[Theroundhousernr 589]

Anybody done this? How about that darn squirrel. If not I'll just order and find out I guess. I can always return. Am I aloud to post a link to amazon?

Edited October 1, 2014 by Theroundhousernr

[bmsgaffer 2,043]

I dont know about Bike tachometers, but several people have successfully puts tachs on their machines.

 

Searched for "tachometer":

[Save Old Iron 1,563]

send me the links - if the coil used by the engine has one trigger input (+ and - on the coil), it is still considered a single cylinder from the standpoint of a tachometer.

[Save Old Iron 1,563]

  

  Second , the onan coil is wired a little different with the positive side going to the condenser. Is this where I would hook up the signal wire on an onan?

 

   Thanks guys Kyle

Onan engines pickup the tach signal from the AC signal off the stator. The 520 tachometers are calibrated to stator output frequency and not directly to "points" opening and closing. The stator frequency ends up being incompatible with 4/6/8 cylinder switch selectable settings.

 

Make sure the tach you choose can condition the points signal (300+ volt negative spikes) and is meant to be hooked directly to points and not an inductively coupled style pickup (pickup wrapped around a spark plug wire).

 

Most of these efforts fail due to motor bike tacks having a readout scale from 0 to 10,000+ RPMs.

The Onan will idle at 2000 and peak at 3600 RPM. Reading the actual rpms on such a large scale meter is rather useless, especially for any diagnostic purposes. The full Onan rpm range may compressed to an inch or so of the meters full range. Trying to tell the difference between 3400 and 3600 RPM may not be possible.

Edited October 1, 2014 by Save Old Iron

[baerpath 517]

I see quite a few of these on the pullers. Thinking of getting one for Marylou's twin for next year. Can hook it up both ways Works on singles twins or more.     http://andytach.com/shop2/index.php/tachometer/tachometer-hourmeter-sensor.html

[Save Old Iron 1,563]

I see quite a few of these on the pullers. Thinking of getting one for Marylou's twin for next year. Can hook it up both ways Works on singles twins or more.     http://andytach.com/shop2/index.php/tachometer/tachometer-hourmeter-sensor.html

 

those would work either way, magnetically triggered or wraps around the spark plug wire  

[Save Old Iron 1,563]

Kyle, got your links

 

ignore the distributor, it has nothing to do with the frequency the tach sees UNLESS you pickup the tach signal from wrapping the sensor around one of two (or more) spark plug wires.

Edited October 2, 2014 by Save Old Iron