I’m looking to put a Tiny Tach on my son’s Tao Tao 110, I believe it’s got a Loncin 110cc engine on it. Does anyone know if these engines fire on every revolution or only on the compression stroke?

 

It fires on every stroke, including the exhaust.

Are you getting this just to measure RPM's? Or to measure accumulated hours on the engine? Accumulated hours can also be measured by installing a digital bicycle speedometer for a lot cheaper. Then you get a speedometer, engine hour meter, trip meter, accumulating odometer, average speed, peak speed, etc. It is resetable and the battery can be changed. It does not a tachometer function though.

 

Ya; sounds good; I've got a couple of those laying around. How do you mount the magnet and pickup?

 

Hay LynnEdwards the main reason for getting the Tiny Tach is the hours meter function.

BTW nether of the bicycle speedos I have can do engine run time. How is a device that dosn't connect to the engine going to tell me how many hours the engine has been running any way.

Ya know for 45 bucks I'll get the Tiny Tach. Hell I spent more than 10 times that on the quad.

Thanks for the info on how often the engine fires.

 

The way the speedo's measure hours on the engine is by assuming that the quad only moves (i.e. wheels rotate) under engine power, and that you don't spend a great deal of time with the engine running while the quad isn't moving.

I bought my 17 function Schwinn speedo from amazon.com for $14.00 including shipping. Like you, I also bought it to keep track of the engine hours (for oil changes), but I really like the speedometer, and the odometer (both the trip meter and the cumulative (total miles) odometer.

This is the speedo I bought (the big black button is a horn switch unrelated to the speedo):



I mounted the magnet on the axle drive sprocket. I used a couple of stacked rare earth magnets (instead of the wimpy magnet that came with the speedo) glued into an aluminum bar bolted to the sprocket. The sprocket is not hardened and drills easily:



The pickup sensor is mounted on a piece of scrap garolite plastic using existing holes on the quad swing arm. You can use any material for this bracket. Fiberglass, aluminum steel, even wood:



To make the sensor mounting bracket template I used beer cartons and scissors. I arrived at the final design by trial and error. I wittled down the cardboard till it looked about right, and if I went too far I traced the too small template onto a new piece of cardboard while adjusting the perimeter as required. Once you have a cardboard template that fits then transfer it to whatever material to be used for the bracket and cut it out.

You can also see the aluminum magnet mounting bar in the following picture. You could also drill the head of a brass cap screw and mount the magnets in the drilled hole in the hex head. Do not use steel bolts to hold the magnet. You want a far reaching external magnetic field to get picked up by the sensor coil, so use something non magnetic to hold the magnet. A steel backplate (where I used garolite) is OK, just don't have steel shunting the north and south poles of the magnet together.






I installed my speedo about a year ago. The speed accuracy is bang on as measured by the radar speed monitor at my local state run OHV park (you do have to measure your wheel circumference accurately and enter it into the speedo).

The sensor pickup wires are too short to reach from the handlebar to the rear axle. I cut the cable and inserted my own two wire cable to extend it. Polarity doesn't matter. Just hook it up any old way and it works.

All functions work except one. The temperature reading reads way high on both mine and my neighbors quad. Once when we were at Hollister Hills State Vehicle Recreation Area both our quads read 127 degrees F. I'm guessing it was about 110 degrees F, but certainly not 127.

 

I like it but I'm still going with the Tiny Tach. I may do both.