Technical knowledge of electronics

Discussion in 'Some Assembly Required' started by Andyvh1959, Jan 11, 2021.

  1. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    I have some very basic understanding of electronics, like what goes on inside transistors, diodes, CDI, or inside the engine ECM. But only very basic stuff that I learned back at MSOE in the early 90's. Perhaps other brighter minds here can teach us details on how some systems on our bikes work?

    For instance, I am trying to install an electronic gauge set from a Vulcan VN1700 into a fairing I am installing on my Vulcan VN1600. I'm working with another home wrench doing likewise on his VN1600 Nomad. He has the gauge set mounted and has most features working, but has yet to get the speedo and tach working. The VN1700 gauge set is very shallow, all the inputs are electronic, and do the automotive style "sweep" when fired up. The ECMs for both bikes are similar, but not enough. For example, both the VN1700 and VN1600 have a speed sensor at the tranny output shaft sending a signal to the ECM and on to the gauges. But each puts out a different signal because of the sensor coil and number of teeth on the output shaft.

    So, am I right to assume all these gauges function on some sort of a voltage signal? The sensor produces a signal to the gauges, water temp, oil pressure, voltmeter, even the speedo, as a voltage signal that is calibrated to show what we need on the gauges. I'm assuming the ECM modifies or refines the signal to a smooth trimmed voltage signal to the gauges so we don't see flutter or twitch on the needle. So on the VN1700 gauges, getting a signal from the speed sensor on the 1600, the signal should cause the speedo to react, but perhaps not at the right calibration relative to the bike road speed?
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  2. VX Rider

    VX Rider Long timer

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    Lets go to a more basic question.

    Do the original gauges function properly when they are installed?

    Do you know 100% that the ones you are attempting to install work properly?
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  3. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    Yes and yes. The original gauge set on the VN1600 (tank console like a Harley) work fine. The gauge set from the VN1700 respond to powering up, all the meters do the power up sweep common to many vehicles these days. The 1700 has an inductive speed sensor (two wire), and the 1600 has a Hall effect speed sensor (three wire). The Hall effect sensor requires a power input to create an output signal. The inductive speed sensor does not require a power input.
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  4. Beezer

    Beezer Long timer Supporter

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    I would put an O-scope on the output signals and get plots for comparison. might have to run on rollers or something
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  5. Fast Idle

    Fast Idle Since the Sixties Supporter

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    Sounds like you'll need to use the 1700 inductive pick-up (AC signal) and not the 1600 (DC square wave). You've got apple and oranges.
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  6. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    Hmm. The VN1700 does have the two wire inductive speed sensor, so that makes sense it's an AC sine wave output. Perhaps the VN1700 ECM trims the signal to make it work for the speedo. The VN1600 has the three wire sensor, which does have a power input from the speedo/ECM, so it would be DC. Good point, I may have to check into the VN1700 speed sensor.
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  7. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    For that matter, it may not even have to be a Kawasaki VN1700 inductive speed sensor. Just a somewhat standard two wire inductive style sensor with the right diameter, depth reach, and mount to suit the VN1600 setup. I found one hunting the web, available at O'Reilly's that may suit. Since Kawasaki and nearly everyone else buys their speed sensors from other suppliers its likely something from Wells or other similar suppliers could fit and provide the needed signal.
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  8. Beezer

    Beezer Long timer Supporter

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    is there a calibration operation on the OEM speedo? there is on aftermarket units. you can adjust the instrument for the proper pulse per mile to get accurate speeds. there are ways to reshape the wave form
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  9. Fast Idle

    Fast Idle Since the Sixties Supporter

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    I just re-read your first post. If the speed sensor signal goes to the ECM and the ECM drives the gauge then switching sensors probably will not work. The ECM is getting the input signal it's designed for. Is it that way on both bikes?
    If the sensors were wired straight to the gauges then yes using the right sensor would probably fix it.
    If the ECM is driving the speedometer and tach it my be by digital data. Know any Kawasaki techs that might could help you?
    It sounds like a cool conversion if you guys can get it to work.
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  10. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    Little update. I was wrong about the speed sensor on the VN1700, it is not an inductive (two wire) speed sensor. On both the VN1700 and VN1600, they do both use a three wire Hall effect speed sensor. The sensor in each case is powered by a 5-volt output from the ECM, and each sensor produces a 5v amplitude square wave output signal. Each sensor has a ground connection, a power connection to the ECM, and a connection to the speedometer. The test for the speed sensor for both bikes is identical per the Kawasaki factory manual for each bike. The output for each sensor is different because the number of teeth each reads on the tranny output shaft is different. The change in square wave frequency is what the speedo correlates to the speed of the bike

    The tach? Well that may be a bit more of a challenge. The VN1700 tach gets a signal from the inductive style crankshaft sensor. The VN1600 has no tach, but it does have two inductive style crankshaft sensors. Hopefully one of those has an output signal the VN1700 tach will respond to and show the actual engine speed.
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  11. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    More update. I found an inexpensive signal generator (SG) on Amazon for $13. It outputs a low voltage square wave, with an adjustable frequency range. I set up my VN1700 gauge set on the bench, figured out how to connect the SG, as the instructions said nothing about hooking it up. Once I got the SG powered and connected to the gauge the speedo fired right up, and the odometer started counting up! So I upped the frequency to 877Hz which the VN1700 factory manual specs for 60mph. Bingo, spot on. Found out the miles on the odo was 18524, and climbing. So I cranked the "speed" up to 100 on the speedo and let it run. Since Friday morning my test has "traveled" close to 2,000 miles and the lawn tractor battery has only dropped from 12.5 volts down to 12.09 volts. All lit up and the speedo holding 100 mph takes very little power.

    I studied the VN1700 manual and I see no schematic connection between the crankshaft sensor and the tachometer. The crank sensor has two wires going to the ECM, and then only two wires from the ECM connect to the gauge set. The schematic does not directly indicate the two wires go specifically to the tach. But, since I now know the speedo/odometer work directly off the speed sensor, and all the other gauge set connections go to fuel sender, oil pressure sender, directionals, cruise, shift indicator, I may try those two wires for input to the tach, but I suspect that won't work. There are two CAN-BUS connections to the VN1700 gauge set, and some electronic tachs get the signal from the ECM, which I think is through the CAN-BUS.

    The VN1600 has two crankshaft sensors, which both output to the ECM on the bike. But there is no tach on the VN1600, and no CAN-BUS either. So I need to dig around on the 1600 to see if either crank sensor can signal the engine speed to the VN1700 tach function. Aftermarket tachs often get an inductive signal from a spark plug wire, or from a positive or negative signal from the coils. Not sure the VN1700 tach can operate directly off that signal.
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  12. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    Latest update. I have been working with Mark Olson, owner of Accutach in California. Mark is persistent and methodical to the point he determined how to isolate the tach from the VN1700 circuit board on the gauge panel, and then designed a controller to use the signal from the crank sensor to drive the tach. Best part is it works! He's had me test the first two prototype tach controllers, which is now able to operate from the crank sensor signal or from the coil input signal. The coil input signal is, um, "dirty" in that it causes some tach needle over-sweep accuracy on strong throttle blips. To get the tach to respond was no easy feat as Mark did not have access to the Kawasaki logic code, so he developed his own control logic to get it work. I'm now mounting the gauge set into the Pacifico Shadow fairing I'm modifying to mount on my VN1600.
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  13. c1skout

    c1skout Long timer

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    Cool! Glad you're getting a workaround to move forward.
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  14. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    I can say that Mark Olson at Accutach in California is the guy to call when you're trying to make a tach or gauge work on whatever vehicle you have; be it a 65 Mustang that you want to install electronic gauges or 53 Morris Minor, or a Kawasaki Vulcan 1600. He knows his stuff.
    #14