Can you use a 2 stroke magneto coil on a 4 stroke engine to run lights???????????????

Discussion in '4-Stroke Engines' started by Samdallas214, Oct 14, 2012.

  1. Samdallas214

    Samdallas214 Member

    This might sound crazy but could you rig a 2 stroke magneto coil to a 4 stroke engine to run a light?

    If not that could add a second 4 stroke coil to run a light set?

    This might sound even more crazy but if you could add a coil/magneto coil the could you add 2 coil/magneto coils 1 for the front light and 1 for the tail light?

  2. Ludwig II

    Ludwig II Member

    Magneto coils powered lights for years, so it's just a matter of matching output to energy consumption and ensuring the bulbs don't blow at high speed or go a dingy brown colour at low speed.
  3. Samdallas214

    Samdallas214 Member

    What is was thanking of doing was to add a rechargeable scooter battery run the coil to the battery and the run the12v LED lights to the battery. that way the battery would stay at 100% charged and you would eliminate the light problems, do ya thank that would work
  4. Ludwig II

    Ludwig II Member

    You'll have to ask somebody who understands ohms and watts and amps, I'm still holding a oil lamp in front of me on a stick.
  5. HeadSmess

    HeadSmess Well-Known Member

    wrap a few turns of wire around the existing coil and attach 2 LEDs opposed to each other. theyll light up.

    your ideas sound, its what the generator coil in a normal momobike with a magneto does. a seperate coil, with less turns...

    simple bit of (laminated-hack apart a transformer) bar with enough wire round it, one end as close to the magnets in the flywheel as possible, bolted down tight. and a rectifier/regulator for 12v DC. $5 on fleabay :)

    leave the ignition coil alone.
  6. Scootmeister

    Scootmeister Member

    Hi Sam. I've done this on three of my engines. I put two coils on my HS 142, one on each of my Homelites. I used a defective HT laminated magneto wrapped with 18 gauge magnet wire. In all three cases the coil works like a champ, not enough juice to run extra accessories, but plenty to run lights and a horn. When I was a kid we had 50cc Ducatis, Bennellis and Cushmans with this setup. My coils will fire indcandescent bulbs, but you get a lot more light from a rectifier and LEDs. I had to modify the plastic flywheel cover on the HS to accomodate the two coils, but the one coil fit within the covers on the Homelites. Once you try this you will never go back to batteries. Good luck
  7. BigBlue

    BigBlue Active Member

    Could you use a lighting coil from a scooter, snowmobile, small engine?

    AKA: BigBlue
  8. Scootmeister

    Scootmeister Member

    You could Chris if the coil in question mates with the curve of your flywheel. In order for the coil to work properly it must fit within .001 of an inch, about the thickness of a business card. Most production lighting coils fit on the inside of the flywheel and the laminated core is shaped accordingly. My custom made coils fit on the outside of the flywheel so I have to grind the core so that both sides are close enough to the magnets to work. For example, the flywheel on one of my Homelite engines is 4 1/2" in diameter. I ground the core on the magneto with a grinding wheel that was also 4 1/2" in diameter to get the same curve. I have already put the Homelite back together, but I will try to post some pictures of my HS142F with the cover removed. Hope this helps.
  9. BigBlue

    BigBlue Active Member

    Pictures are worth a thousand words. I understand what you are saying, but until I see it, I don't fully comprehend.


    AKA: BigBlue
  10. Scootmeister

    Scootmeister Member

    Chris, wasn't able to take photos today because I was too anxious to try out my new coil with a rectifier and new LED tail light, actually a side marker light with two LEDs that I got from Walmart for $6.00. I'm happy to report that it works like a champ and the LED tail light glows like devil eyes. Eventually I will swap the incandescent headlight for a LED light as well. I installed a simple toggle switch in the circuit so I can turn the lights off to charge a battery or cruise in "stealth" mode. I will not be going back to batteries!!!
  11. BigBlue

    BigBlue Active Member

    No problem on the picture - I understand. Look forward to a post of your project.

    AKA: BigBlue
  12. Scootmeister

    Scootmeister Member

    Chris, see if these pictures help you. The first pictures are the coil I made for the HS142F, the second is the coil I made for my Homelite engine. I have read that the more wire you wind on the core, the higher the amperage, so I loaded them up with as much 18 gauge wire as they could hold. You will note that the curve on each coil is different because the mounting position of each is different. In both cases I had to fabricate a mounting plate to hold the coil in proper relation to the magnets on the flywheel. The rectifier on the Homelite bike is a 3-phase unit from a Yamaha motorcycle. I finished the wiring today and it works great. The HS is not being used currently, but bench tests showed it works as well. I'll be mounting it on a new build shortly. Let me know if you have any questions.

    Attached Files:

  13. BigBlue

    BigBlue Active Member


    Thanks for sharing the pictures and ideas - it looks great!

    Is that a stock HS magnetic coil for the HS engine with the plug wire and housing removed?

    Excuse my lack of knowledge on electricity, but couldn't you attach a lighting coil to the arms of the added magnetic coil via two heavy wires. Or mount a lighting coil across the added magnetic coil arms? Looking at Wonderful Creations lighting coils, they just attach the lighting coil to the existing magnetic coil. Wouldn't wire accomplish the same thing? Electricity is generated when the magnetic passes the added magnetic coil up the arms. So if a lighting coil is attached with two wires to the magnetic coil, isn't the same thing happening? Or if you attach the lighting coil directly to the magnetic coil?

    I don't know if you'd accomplish anything better than what you've done, but I just had a thought:idea:

    AKA: BigBlue
  14. Ludwig II

    Ludwig II Member

    Scoot, you just answered all the questions I wanted to ask as well. It'll sort it nicely when I build mine.
  15. Scootmeister

    Scootmeister Member

    Chris, my coil started out as an ignition coil for a HT China Girl. On the two stroke engines, the CDI is separate from the magneto. On the HS engines, the CDI and magneto are integrated into one unit under the flywheel cover. Also, you need to keep in mind that a magneto has two windings, a primary and a secondary. The primary picks up the magnetic field from the magnets and transforms or inducts it to a high voltage current in the secondary coil which is connected to the spark plug wire. The windings are actually wound on top of each other and separated by a piece of non-conduction paper. A lighting coil is one continuous winding that "pipes" the inducted current out the lead wire directly to your rectifier or to your lights if you aren't converting your current from AC to DC. The reason I use a rectifier is LEDs do not like AC current. Incondescent lights, on the other hand, don't care if the current is AC or DC. Hang in there, once you learn this stuff it will serve you well whether you are working on your car or rewiring a lamp!!!!!
  16. Samdallas214

    Samdallas214 Member

    Thanks so much I just knew it had to be possible, the pictures,makes it real simple.
  17. Scootmeister

    Scootmeister Member

    You're welcome, Sam. Let us know how yours turns out.
  18. MotorbikeMike

    MotorbikeMike Member

    Hi Scootmeister, congrats on your lighting coils! I have long believed that someday we will be saddled with the necessity of lights, just to be allowed on the road.
    One of the major beliefs that we have here at EZM is, that we do not ever want to let the lack of any particular engine, stop us Motor Bikers. For this reason we embrace many engines, as power plants, tho I am not familiar with the Homelite, was that a Chainsaw, or backpack blower or?
    Also, I was studying your coil arrangement, you soldered one end of the coil to the horse-shoe bar, Right?
    As I looked at the wire you used, is that 18g solid with plastic insulation, like THHN? Do you have an approximation of how long the wire you used is so that I might try this at home?
    Thanks for your great application of this idea.

  19. Scootmeister

    Scootmeister Member

    Lighting coils

    Hi Mike: I've used two different Homelite chainsaw engines on my bikes. Both are completely stripped of extraneous parts down to the engine core. Both have fully adjustable carbs, reed valves and centrifugal clutches that have been converted to a sprocket drive. One is 3.3 hp and the other is 4.1 hp so they pull pretty well. On the design of the lighting coil, yes one end of the wire is grounded to the steel core so the current can run through the coil. The wire I used is 18 gauge magnet wire which is simply copper wire with a lacquer coating for insullation. I wrapped as much as I could get on the core,, the more you wrap the higher the output. If you use lighter wire you get higher voltage, larger wire yeilds higher amperage. These coils are small so you're not going to get enough current to run accessories, but the rectified current drives LEDs fine. I'm going to put a gel battery on one bike for consistency. Good luck, let us know how your project comes out.