80cc Bicycle Electrical

Model H2-80 (this is the latest, more robust version)

Kill Switch
The controls all went smoothly, but I recommend filing the sharp edges from the kill-switch housing. I got a cut on my knee from it.



The instructions say to wire the kill switch across the wires to the ignition module. This is scary because it shorts the magneto output, and the forums say this is a major cause of magneto failure. I removed the yellow pushbutton and replaced it with a small DPDT or SPDT slide switch with the screws supplied with the switch under the original pushbutton housing. Of course a rectangular hole must be made for the side. This switch is then wired in series with ONE of the ignition module wires.


Note that the output from both the blue and white wires is AC current.


First I made this test circuit to determine what the actual rectified voltage is. The 170 ohm resistor was chosen to simulate the trickle charge load on a fully charged battery pack.


The resistor value is determined by the desired trickle charge current. From experience I believe 40 ma continuous will not harm the batteries I am using. Note that chassis (the bike frame) is positive ground.


These are high intensity LEDs rated at 3.5 to 3.7 volts, 20 ma.


Finished assembly measures about 7/8" X 1"


Headlight on. These is a drawback with this... Oncoming motorists keep their bright lights on wondering what is making a very tiny bright light.

The battery pack is ten LiMH cells in series attached to the top of the "trunk" lid with aluminum flat stock. Then polyurethane glue was trickled in between the cells to keep them in place.

The crescent shape at the top houses 4 LEDs behind the red reflector to serve as tail lights.

Ignition module

The ignition module has two ears that are meant to accept small, long bolts. I saw the ears were starting to bend before it was held in place tight enough for me, so I replaced the bolts with a nylon cable tie with inner tube rubber between the module and frame.

Spark plug gap 

Some say theirs works better with the gap set at .020, others .040, others, .030. I left mine at the original .032. My guess as to why it varies is the type of gas (some has ethanol) or type of oil. The motor was shipped with a Weixing Z4C plug. You can use (and it is recommended for better performance):

NGK B6HS

Autolite 425

Champion L86C

Links

MotoredBikes.com Lots of info. This is my favorite.

Kings Motor Bikes Instructions, parts

Spooky Tooth  parts, forum

MotorBicycling.com Excellent forum

Gordon Jennings Archive Two stroke handbook (free)



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Copyright Bill Weller, 2008 All rights reserved.