Trail tech vapor and tach... Does it work for you?

[CoconutPete]

I'm considering the trail tech vapor. The guy from trail tech says the points ignition of the xs is too noisy to get a good reading for the rpm's. I dug through the archives and only found:
A: people who said it worked (but no details)
B: people who said it didn't work

So... Is there anyone out there using one who is willing to share how you got the tach to work?

Thanks

 

[TwoManyXS1Bs]

Maybe you'd like to pursue a trigger input filter, between the coil's grounding side and the digital tach.
If you look at my Timing light circuit, post #11 in this thread:

http://www.xs650.com/threads/an-led-ignition-timing-light-experiment.44586/

The components D2, C2, R5, and R6 form a filtering type of 'capture-and-hold', reducing the kettering ringing to a single, positive pulse. I would expect that a good digital tach would already have something like this implemented, knowing that kettering ignitions have been around a long time and always had this characteristic ringing. When I hung a scope on member DogBunny's TCI ignition, there was much less ringing, but still enuff to require input conditioning.

You could show that thread, with the scope snapshot and the circuit, to your TrailTech rep, see what he thinks...

 

[grizld1]

This is the second thread on this topic in as many days. So here's the same answer again. 2M, you know more about electronics than I'll ever learn, but this is based on experience.

Spiking due to electronic noise is a common problem with aftermarket tachs. Expensive ones like the Veypor data logger from Nonlinear Engineering have programmable filters. Cheap ones like Trail Tech and Acewell instruments don't, but the solution is simple. Install a 1 megohm resistor in the line that carries the signal from coil to instrument right after the coil. If you still get spikes, add resistors. If response is to slow, try less resistance. That's all you need to do.

I should add that this is only an issue with breaker point and the cheaper aftermarket electronic ignitions that are just about all that's still available for the XS650. The Probe ignition that I currently use has a tach signal output from the igniter box, and no damping is needed. Because XS650 and other vintage Jap bike owners were unwilling to pay an extra $50 or so for quality, Probe Engineering has discontinued production of motorcycle ignitions in favor of operations that carry their own weight. If you have a Boyer ignition, remember that when your timing plate warps.

 

[TwoManyXS1Bs]

Griz, I'll always bow to experience and successful field fixes.
Otherwise, I'm just guessing, and seeing if stuff sticks to the fan blades...

 

[grizld1]

I can't take credit for the fix, 2M; that goes to the tech people at Electrosport, where I bought the Acewell gauge (I was using a Boyer ignition at the time). Electrosport no longer sells Acewell gauges, which have almost doubled in price since I bought mine. They're currently available from Dime City Cycle.

 

[CoconutPete]

I realize there are many threads about the trail tech and about aftermarket tachs in general.

What I couldn't find in any of my searches was feedback from someone who had actually installed a trail tech vapor and done the resistor fix and reported that the tach worked.

I did look at the Acewell gauges, I just don't like the 524423234 LED's they have in them. I'd love to get a tach/speedo combo in a round housing, OEM style, but they seem to be sparce.

So if I read your diagram correctly, this is what you are suggesting:

(in this order)
Rectifier diode
330pF, 500V capacitor
1 meg, 1/4 W Resistor
100K, 1/4 watt Reistor

 

[TwoManyXS1Bs]

...So if I read your diagram correctly, this is what you are suggesting:

(in this order)
Rectifier diode
330pF, 500V capacitor
1 meg, 1/4 W Resistor
100K, 1/4 watt Reistor

Well, not that one, specifically. It's a food-for-thought concept. That particular circuit conditions the coil signal to a level suitable for my device, converting a ringing +/- 150volt signal to a single, positive pulse of about +15volts. So, it both removes the 'noise', and drops the volt spike to about 1/10 its value. I don't know what the Vapor expects for a trigger signal, that's for the TrailTech rep to determine.

Now, if I wanted to put one of those things on my bike, I'd probably crack the thing open (happens a lot over here), and reverse engineer the input stage to see whut's goin' on in there...

 

[bikefreak69]

Good info,my Trail Tech tach has never worked correctly from day one.The rest of the unit works just fine.I will try the resistor and let ya know if that cures the tach jumping all over the place issue.