Magneto interfering with aftermarket lighting system?

Discussion in 'Electrical' started by P3_Takuto, Sep 7, 2015.

  1. P3_Takuto

    P3_Takuto New Member

    So I have a brand new Skyhawk GT5A 66cc engine and I've got it running great, so it's now the end of the day and I have an aftermarket headlight, brake light and turn signal setup on my bike and so I turn on the system and nothing out of the ordinary, now I start the engine and as it kicks in the turning signals wouldn't work which never happened before with my older engine so I cut the engine and it was working again. So I'm thinking that since its a new engine it's vibrations are effecting the switch, so I remove the computer from the frame and start the engine, same result so i reattached it thinking ill get to it later. i start riding home (carefully i add) i found something strange. Out of habit I try the signal switch to turn and my finger bumps into the engine kill switch and the signals start working again until I release the button. So now I know that the only way I can signal is by holding the kill switch to cut the electrical current to the engine. Could it be the magneto causing an electro magnetic interference? It never acted like this with my old Skyhawk engine with probably a weaker magneto. Just trying to think of any way I can get around this and has this ever happened to anyone else?

  2. butterbean

    butterbean Well-Known Member

    Hmm, I'm assuming your lights and your killswitch are both grounded to your frame? If you can electrically separate your lighting system from your frame, thinking this may solve the problem.
  3. jaguar

    jaguar Well-Known Member

    how close is the high voltage coil (which is an integral part of the standard CDI) to the electronics for the signals?
  4. P3_Takuto

    P3_Takuto New Member

    Ill try rewiring the ground to another location and the CDI is aprox 2-2.5 feet apart
  5. jaguar

    jaguar Well-Known Member

    that is far enough away to not cause interference.
    probably is due to a voltage change when the kill switch shorts out a portion of the stator coil. I would look into what that voltage change is with a good voltmeter. Maybe you will need a voltage regulator
  6. HeadSmess

    HeadSmess Well-Known Member

    this is the key... common earthing issue.

    the magneto utilises AC current/voltage. the frame has a resistance, and any voltage across it results in a current through it. when that coil sparks...a few thousand volts across a small resistance still makes for a fairly large (spiky) current.

    it alternates, it is not just a negative earth! positive on the charge cycle, negative on the discharge... or vice versa... you should get the idea.

    whereas your indicators and such forth are DC powered.

    not sure what differences you have between former engine and this one, but im with the bean...separate your earths. use the frame for the engine/ignition, as that is necessary. (spark plug is earthed through the head...there has to be a return path to the cdi!)

    use twin wires for the other electricals.

    you could try decoupling capacitors and diodes but its seriously over complicated compared to adding a wire.

    as for magneto interference... get an led torch, hold it close to the cdi and see how far it will get before it starts turning on by itself...usually 6 inches or so. could try wrapping the cdi in a nice little copper box to suppress any EMI...
  7. butre

    butre Well-Known Member

    after my first bike I don't ground anything to the frame. ended up with a 12v SLA battery pushing a little under 17 volts before any symptoms showed up, only thing I can figure is that after the electrons from the ignition system were done doing their thing they ended in my battery.
  8. HeadSmess

    HeadSmess Well-Known Member

    electricity is WEIRD.:wacko:

    i fiddle with lil tube amps for the guitar because i can... have to use them or the few factories still producing will shut down,
    2... its fun seeing what sounds you can get from a weird obsolete tube that will never ever serve any other purpose... collected enough. might as well use em!

    where was i?...

    oh. now, i can bias a tube so a 4 volt input will overdrive it, but can set it up so its own voltage drop due to the input will allow it to take a 20volt input before overdriving as it adjusts its own bias...

    static versus dynamic characteristics. ouch. i thought making tuned pipes ate up paper? printing out the same graph 20 times eats paper! i cant work on a puter when it comes to this stuff.

    and the maths! oh my lawd, the maths! f*c*(Rl/Ri)!!!!

    but makes for a really nice controlled overdrive :)

    yeah! try and do THAT with ya silly chips! pffft. transistors...
  9. butre

    butre Well-Known Member

    audio guys still love tubes for the warmer tone they give over transistors, so I don't think they'll be going anywhere anytime soon. it blows my mind that they used those imprecise and often downright weird things in computers for so long. given the fuzzy sound that tube based audio equipment has I'd hate to see what kind of screwy **** it did with the ones and zeroes
  10. HeadSmess

    HeadSmess Well-Known Member

    this is where its peculiar...

    a hifi can cost over 100k... before even buying speakers(add another 75k...each!), but oh my...

    you have to actually listen to a high quality one to realize why someone pays that much.

    a tube can distort, its the whole reason music got to the point it did in the 80's or so, until the synth and the digital revolution made an appearance and destroyed everything. but its the way it does distort thats the key!

    in hi-fi, with a bit of number can get a lot of amplification, a lot of dynamic range, and of course... NO distortion!

    in fact, armed with just a multimeter and a data sheet, you can make a pretty good tube amp, with say, 1-2%distortion (not great but definitely listenable), with absolutely NO MATHS!

    hifi is NOT guitar amp tech though... where you WANT distortion...

    dynamic range is important. transistors will always require several more stages to achieve the SAME gain, with equal distortion...and so lose all the dynamics. each stage compresses the signal. each stage reduces the extremes between soft and loud... each stage attenuates certain frequencies... add it all up and the more stages...the worse the reproduction gets. every component adds noise.

    a 10watt class A tube amp will put even 100 watt solid state to shame for sheer volume... and wont burn out your speakers due to driving straight DC through the voice coil when it starts clipping signals.

    a transistor/solid state is perfect for switching on and off, ie...puters. this is where they really reign supreme. small, low voltage/power, cool running, cheap, and easily made in miniature. they dont require a heater, high voltages or any of the dangers associated with HT supplies. smallest tube i have is still as fat as a pencil and about 1 inch long...

    but they arent so good as LINEAR amplifiers. hard to explain that one to anyone that hasnt delved into theory of tubes much. i had this argument with an electronics engineer, him saying that tubes are obsolete and distort everything... and now he makes top-end tube amplifiers for studios... go figure!

    they distort LESS than solid state. a transistor has a terribly non-linear amplification curve, takes a lot of maths to get it approximating a straight line at all. and then the range it can cover is limited... ie, from 0.6 volts to 0.9 volts...anything below, its OFF, anything above...its ON... all this nonsense about thermal runaways and negative coefficients etc... temperature compensation, yarda this yarda that...

    while a tube can swing from nothing to say, 300volts... and do it fairly well in sync with the input... only a little adjustment here and there and its near perfect.

    the guitar amplifier is just a special case where, in the pursuit of more volume, this side effect, overdrive, started to become apparent...

    not from intentional design, but by accident! all that great music...floyd, berry, clapton, whatever...all due to an accident!

    of course, now its been studied and perfected to the almost nth degree... you can go either way...crystal clear perfect audio reproduction, where you can seriously hear the splices from the tape editing, the guy out the back that coughed halfway through a take, to absolutely filthy shredding sounds...

    solid state distortion, due to the harmonics created, always sounds distinct to tube distortion.

    and theres about five different types of distortion...some pleasant, some not so pleasant. its finding the blend that works best that takes practice.

    this is before contemplating how the speaker itself affects things. thats a whole other kettle of fish!

    they also have the advantage of not requiring any input current. you can have a voltage without any current...thats electrostatics. they can reference the changes in voltage across a resistive divider...without becoming a resistive element that affects the potentials across the divider itself. imagine a multimeter that can take measurements but has no actual circuit inside to affect what its measuring...
    but you cant have a current with no voltage! (E=IR)and all silicon junctions require 0.6v to start conducting... 0.2v for special items like schottky diodes. unfortunately, they require a minimum current to reach that voltage.

    to make an analogy... transistor, to get the valve to open, you have to pour some water down the inlet. so you need to replenish the water supply. (current=flow) this places a load on the signal source. this creates its own type of distortion, and effects the way the signal source operates.

    tube, to get the valve to open, you simply have to lift the cup up, no need to spill any...(voltage or potential=height) this places no load on the signal. no load, no distortion or unexpected effects.

    my head hurts. :wacko: