Rectifier burned

[Axelhe]

Hello! I´m totally new to this bikes. Just bought me a fun little GT125, that I hastily destroyed :/
The battery was dead so in order to test the electronics I removed the battery and hooked the bike up to a car battery.
However, I managed to reverse the poles(!) with smelly smoke as a result. I think the smoke originated from the rectifier.
Now the bike is dead, all the lights that worked before still works, but the bike wont start however much i kick.

My theory is that the coils runs on battery-power, but the battery is dead and the rectifier burned so there is no sufficient power to the coils, therefore no spark.
What do you think? Can it be that I burned something else?

If it is the rectifier, where can i find a replacement? Would it not be possible to use a cheap rectifier from another model and make of bike?

[jabcb]

What year is your bike?

Do you have the wiring diagram?
Is it kick start only?
Is it 12 volts?

If it is kick start only & has an alternator like the GT250, then you can use an aftermarket rectifier/regulator that costs something like $50.

[Alan H]

Doesn't the gt125 have a dc generator/starter like the gt185?
If someone posts a diagram, we can work something out.
Reverse battery polarity won't take out a rectifier, but if there's a regulator, it might shag that.

[Axelhe]

The bike is from 1980

It is kick start only (I think it is just the GT185 and the really big ones that has a starter.)
It is a 12V system

The smoke seemed to come from the rectifier, but I'm not sure.

However! Some tinkering yesterday yielded good results! After replacing the dead battery with a brand spanking new one i got good spark! So the coils seems fine. But she was totally drenched after my futile tries to start. So I disconnected the fuel tank and kicked like a maniac and... WROM! She starts! Phew

But when measuring the voltage over the battery with the motor running the voltage jumps around erratically from 12,30V to 3,0V and everything in between.
Something is not working as it should.

I can´t find a electrical diagram for the GT125, but here is one for the GT250, I think they are similar.
http://www.oregonmotorcycleparts.com/Di ... T-250A.JPG" onclick="window.open(this.href);return false;

[pearljam724]

I've burned a rectifier also. It's wise to make sure all electrical connections and wires are very clean. A connector or wires may need replaced due to age alone. If not. Rust, dirt, grease, accumulation will cause electrical resistance. The result can be parts not working properly or destroyed due to heat.

[jabcb]

Is there an online parts diagram for your 1980 GT125?