Upgraded Rectifier blows fuse 1973 GT250

[sethrobb16]

Hello everyone! I just upgraded my rectifier on my 1973 GT250k to a Tympanium Regulator/Rectifier. I hooked everything up and it was working great, electrical system was good and my battery was being charged- but when I turned on my headlights, my fuse was blown.

I connected one yellow wire from the tympanium to the red with green trace wires (there are 2) from the Suzuki original wiring. The red with green trace connect to different coils of the stator. One comes there directly and connects the DAY coils so that it charges with the lights OFF. The other set of coils are wired through the light switch so that when the lights are ON, the other set of coils is connected to charge the battery faster. The set of coils are green/white at the stator and switch to red/green at the light switch.

The other tympanium yellow connected to the yellow with green trace which is the other side of the charge coils

Tympanium red goes to battery and also to the main line with the fuse

Tympanium black goes to battery and grounded on my bike

How can I fix the wiring so turning on my headlights doesn’t blow a fuse?

[jabcb]

The alternator has a charging coil and a lighting coil. The lighting coil is switched on only when the headlight is on. That's how the GT250 can get away without having a voltage regulator.

There are 2 ways you can wire up the GT250 with a modern rectifier/regulator like the Tympanum. You can continue to have the lighting coil switched with the headlight. Or you can wire up the lighting coil so that it is always on, which is the way we did the 73 GT250K cafe build.

Diagrams for both ways are in my old post here:
http://www.suzuki2strokes.com/forum/vie ... or#p121472

The T250 & GT250K have the same wiring.

[sethrobb16]

Those diagrams are great! Thanks so much. I hope bypassing the light switch entirely will prevent the fuse from blowing every time I try to turn them on with how I have it wired now. Ill be sure to update after i complete the re-wiring

[sethrobb16]

Also out of curiosity, is it the sudden addition of charge coming to the rectifier that blows the fuse? Rather than it constantly flowing all the time by having the lights up to be on all the time?

[jabcb]

With everything correct, having the lights on all the time is not an issue.

I didn't think through how you wired it up to identify the issue. Lots of people have asked about the modern rectifier/regulator upgrade. So I made these diagrams to make the explanations easier.