Suzuki GT500 Electrical Problem

[bigmick49]

I have a 1976 GT500 with 2 electrical issues.
No spark with the ignition turned on but healthy spark with the ignition turned off. The kill switch works as it should but only with the ignition in the off position.
Replacement blinker unit will only work with the earth lead disconnected. Connect the earth lead and the neutral light blinks and the blinkers do not work disconnect the earth wire from the blinker can and the blinkers and neutral light work OK.
I have a replacement after market ignition switch which for all intents and purposes is identical including the wiring. With the ignition switch in the first position all works including blinkers (with the earth disconnected) and all the lights and horn. The ignition switch in the 3rd position nothing works.

[jabcb]

You may have the wrong ignition switch.

On the T500 & most other Suzuki two stroke street bikes from the 1970s, the ignition is powered by the battery.
The ignition switch connects the battery to the coils in only the on position.

The GT500 has PEI ignition, which is self-powered.
In the off & parking positions, the ignition switch grounds the PEI ignition to prevent the bike from running.
In the on position, the ignition switch does not connect the PEI ignition to anything.

Use a multimeter to map out how your ignition switch works & compare it to the wiring diagrams.

The T500 wiring diagram is:
The GT500 wiring diagram is shown as a change to the T500 wiring diagram & is:



Do you have an aftermarket turn signal flasher?
If so, which one do you have?

[bigmick49]

You nailed it mate the switch is wrong. When the switch is on it turns on the electrics but grounds the ignition circuit. And when off well its the opposite.
As for the blinker can it is aftermarket and is just simply a 3 wire replacement for the original so the included paper work indicates.(no brand)
I will have to source the right switch although searching the part No I have ( 37110-25317) is proving difficult unless there is an updated part No.

Cheers

[jabcb]

The latest part number is: 37110-25319

The ignition switch is still available from US Suzuki.
http://www.buymotorcycleparts.com/suzuk ... 6021140020

There are a few listed on eBay too.
Suzuki used PEI on a bunch of dirt bikes, so don't be put off if the listing includes TS-model bikes.

-----------------------------------

There are two types of flashers.

The stock flasher is load dependent.
This type flashes correctly only when the turn signal bulbs are the correct wattage & both work.
For this type of flasher, you need a flasher matched to the bulb wattage.

Load-independant flashers do not rely on the bulb wattage to flash.
They flash even if one of the bulbs is burned out.
You can get one of these flashers at an auto parts store that will work on your bike.

Is your flasher for a vintage british bike?
Your bike has negative ground. Early british bikes are positive ground.
A flasher for a vintage british bike might have to be wired up differently for it to work on your bike.

[bigmick49]

Thanks for the part number I have seen that part No on eBay and yes it was for a dirt bike and given that I am from Australia eBay is my best option.
As for the blinker the replacement is load dependant 2 x 21w and 1 x 1.7w but for some reason does not work when the earth lead is connected. The blinker is being used on the GT500 Suzuki.
I take it that the ignition switch you mentioned has orange and red contacts open and the black/yellow and black/white contacts closed when in the off position?
And I though the Can Bus system on my BM was a pain.

Thanks for your help

[jabcb]

red => battery +
orange => hot that powers the bike in the on position
So red to orange contact is open when in off & park positions.

black/white => ground
black/yellow => PEI
So black/white to black/yellow contact is closed when in off & park positions.

Additional contact is to power taillight in park position.

[Alan H]

Is your flasher for a vintage british bike?
Your bike has negative ground. Early british bikes are positive ground.
A flasher for a vintage british bike might have to be wired up differently for it to work on your bike.

Not sure which British bike had positive earth and indicators, and I've had Britbikes back to late 50s.
But unless it has a diode in the circuit, it would probably work anyway.
Earliest I remember was an Ariel Leader (early 60s) with fitted indicators standard.
Most early British bikes were 6v - up to mid/late 60s anyway.

[jabcb]

Is your flasher for a vintage british bike?
Your bike has negative ground. Early british bikes are positive ground.
A flasher for a vintage british bike might have to be wired up differently for it to work on your bike.

Not sure which British bike had positive earth and indicators, and I've had Britbikes back to late 50s.
But unless it has a diode in the circuit, it would probably work anyway.
Earliest I remember was an Ariel Leader (early 60s) with fitted indicators standard.
Most early British bikes were 6v - up to mid/late 60s anyway.

I don't know if any British bike has positive-ground 12V + turn signals.
Just included it as a possible reason for his problem.

I have a modern Triumph but am definitely not an expert on vintage british bikes.
Have never even actually ridden a vintage british bike.