Hello everyone! Looking for some help

[50ccSwapper]

Hello, I have gotten some great info here in the past and have run into a problem i could use some help with.


I am swapping a 50cc kazuma engine into a ct90 frame, the engine has 4 forward gears and is electric start only, it has 5 wires coming out of the crank case.

Now that i have it running I don't think the battery is charging. When I rev up the motor it shows about 12.8 volts with the battery in place, without the battery it reads 5- 7.5 volts. The yellow wire going into the regulator reads about 10 volts ac. I thought it might have a 6 volt regulator so I swapped it but the voltage remains the same.


Is the stator going bad, or a wiring problem? any help is appreciated, Thanks!

[stewbrash]

I don't know if this helps but on my Z50 clone the yellow (and the white) wires each put out 20 volts AC...which then goes to the transformer/rectifier to come out 13-14 volts DC...so it's possible you have a 6 volt system or it's 12 volt and it's bad. Check the white wire too. The blue with a white stripe wire is for the ignition trigger puck, the green is the ground and the black goes to the other end of the trigger puck (although I've seen those 2 switched.) Also - 12.8 volts should almost be enough to keep it charged, if you ride it enough. Mine is always sitting at 12.3...not running.

[lokie56]

Just a comment about my old '67 Ducati's aged electrical system, that I'm presently running. I bought a regulator from a local motorsports store years back for one of Schwinn's 150cc scooters as a back-up if one of my clone bike's regs blew.

It was too big for mounting to my old Honda Cub with the pitbike engine, but I noticed when I got my Duc running, that the open circuit voltage of the lighting AC coil would rise above 11 volts at about 3000/3500 rpm, generally this circuit runs a 6 volt, 35 watt/6watt pair of headlight and taillight incandescent bulbs and the voltage drop is really obscene with the stock lighting. French mopeds have better lighting than this old Italian bike.

I converted the Duc over to a new, 12 volt wire loom and headlight reflector shell and Ba-15 LED headlamp/1 watt parking/running lamp Ba-9 LED bulb at about 10 watts and a 2 watt dual brightness 1157 LED corncob tail/brake, and when hooked up this magneto's circuit to the Schwinn regulator and a 12 v 7 ah sealed battery, I could easily keep the charge above 13.2v at normal riding RPM with the headlights, tail light and turn-signals all running ( LED too.) It was charging the battery fine in normal use. I never found that this battery would fall below 12.6 volts on this anemic old 6 volt AC lighting circuit. Which makes me wonder what other bikes from this era could also be converted to 12 volt LEDs?

Where I'm going with this little novella is:.. You might look into converting your running lights to 12 volts LED lighting as an 8 watt equivalent LED headlamp's lumens output is close to 50 watts of Halogen incandescent lighting. This will require some advanced electrical fabrication and automotive electrical background.