Tachometer

that last one needs a electric sending unit and drive ratio thing,if you get a tach you want everything included and make sure its for your type of engine.
 
Hey guys, can i take a tachometer out of a car and put it on my bike? If i find something within the rev range of the bike obviously im just wondering if a car one needs more of a pulse from the coil than the bike does? I mite go get one from a junk yard and do some experimenting unless im told its impossible.
 
not only that, there 4 strokes so they only fire every other revoloution where as the 2 stroke fires every revoloution.. and they also require 12v feed... theoreticly a 2cyl 4 stroke tach would work and read correctly on a single cylinder 2 stroke but that still leaves you without the 12v supply
 
Cabinfever1977 said:
12v cordless drill battery recharges in 1hour last for days $18 walmart.
Click to expand...


should have specified more... car tachs use a 12v signal ( along with a 12v feed ) ( DC ) from the - side of the coil. it switches on and off and the tach 'counts' those pulses..couldn't use it on a High voltage A/C signal, like that of a magneto.
 
IMHO Tiny tachs are a waste of money.. they read in digital and because of that, they have a 2.5s response time.. that means if your running without a governer, you could grenade the engine from over revving because the tach will always be 500-1,000 RPM below actual on a steady increase..

hit up the go kart racing sites, they have fast acting analog tachs that will run off inductive timing on single cylinder 4 strokes
 
Ok, I'm a real "Johnny-come-lately" on this thread, but I've just checked into this meter (from 2 different sources) for my 66cc 2-cycle "Jet" kit and find that its' update time is a whopping 2 seconds! Seems waaay too slow. Small diameter tachs are available for the Harleys for under $40 on eBay...2 cyl., 4 cycle = 1 cylinder 2-cycle?...right? I just don't know what the pickup method is..?...probably not Hall Effect or inductive, the (only?) 2 types that might work with the 2-strokes...? The Whizzer now has an accessory, std. on their "Ambassador" model, # WK-400NE Hall Effect tach kit for $71.75, but that's a 4-cycle (also 12 volt), so no-go on a 2-stroke. Anyone have any luck with the Harley item?
 
my thinking is 2 cyl 4 stroke would work for our china engines if it were the right pickup type.. problem I see is, Harleys use a 12v coil, and the tach likely needs a 12v feed as well as the switching 12v signal from the - side of the coil...

I'll agree, with a 2.00-2.50 second response time, Tiny tach's are worthless..your engine could be blown b4 the tach will show what's going on
 
RPM-meter

Does anybody know how to measure RPM's? Has anybody some electronic circuit diagram representing measurement on LED's line or LED display? If I would have it I could make and test this device.
 
Re: RPM-meter

Digital Tachometer Kit

Look in the PDF for the actual schematic. I don't think it includes the hall-effect sensor, so you'd have to add that yourself. The Melexis 90217 is a good one.

Edit: Not to hijack the thread, but could you possibly run an inductor in parallel with the HV spark plug wire to "sense" when it fires the plug? Just a thought.
 
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Re: RPM-meter

I use something called Tiny-Tach. It shows RPMs and Engine Hour run time. When I hit 10 hours I change the oil (4 stroke).
 
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