Project: Black Widow
- Thread starter ubernoob51
- Start date
I built a motorized bicycle about 15 years ago with a 5hp Briggs flathead and wanted a lighting/charging system. It's driven like a Whizzer with belt primary and final drive. So my friend Dan machined the jack shaft double pulley with a pocket to fit a Sturmay Archer Dynohub. It usually goes in the wheel hub of a pedal bike and puts out 6v at slow speed, but when it spins on a motorbike it delivered about 87vAC. I looked for a rectifier/regulator for months with no luck. Couldn't find specs on any of the available small engine units. We needed to charge a battery pack hidden in the headlight that fed 6v DC to the LED headlight and tail/brake light. I was at a local swap meet and saw a box full of cell phone and cordless tool chargers for 50 cents each. Each one had listed the AC input and DC output voltages. Of course all were 120v AC input but had a large variety of DC output voltages and amp ratings. I realized that they were basically regulator rectifiers, so I bought a dozen or so with different output ratings and made a test unit with an electric motor to spin a Dynohub at approximate motorbike jack shaft speeds. It didn't take long to find a suitable unit and we installed it under the seat. It's been working ever since keeping the batteries up. I'm not sure you can find one that will suit your 30 AC volts, but it's worth looking into.
the engines on my black widows are the same... HS50 with smaller alloy hs40 flywheel and round blower housing. dellorto ua19s carb and the stock black widow exhaust. governor removed.
i would change to the newer jackshaft style that does not use rollpins. That's the old style. For $25 you can get the new style which is a lot better/easier.
i would change to the newer jackshaft style that does not use rollpins. That's the old style. For $25 you can get the new style which is a lot better/easier.
Running an incandescent bulb with the voltage regulated lighting coil. Waiting on an LED one to come in, one of the filaments in the bulb is burned out. Second pic is of voltage regulator I bought. It needs a rectifier before the regulator though, but single-phase rectifiers are cheap and easy to find.
