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GT 80


kirkmears
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Hello everyone

I've had the bike for many years, but just now really started working on it and able to start it for the first time. I've tried two different carbs, the first one didn't even fit. I had the tank vatted and cleaned and installed a new fuel filter. The carb could be dirty or the petcock is the wrong direction since I don't understand which direction is which :blink: . The bike finally started and was running fine for several minutes (5+), then it revved up and hasn't been running right since. Now it's difficult to start, but when it does, it just revs up and dies (<10 seconds). Is this tale-tale signs of an air leak? I am mechanically & electrically inclined, but this is my first time to even mess with a two stroke. The individual that had the bike before me had removed the lights and the bike even started without using the run/stop selector (it's been rigged). Are there online wiring diagrams for these? My best guess is that it's a '79ish model. I did find this link, but my symptoms are just a little different...

:help:

Thanks for any suggestions! :)

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Hello everyone

I've had the bike for many years, but just now really started working on it and able to start it for the first time. I've tried two different carbs, the first one didn't even fit. I had the tank vatted and cleaned and installed a new fuel filter. The carb could be dirty or the petcock is the wrong direction since I don't understand which direction is which :blink: . The bike finally started and was running fine for several minutes (5+), then it revved up and hasn't been running right since. Now it's difficult to start, but when it does, it just revs up and dies (<10 seconds). Is this tale-tale signs of an air leak? I am mechanically & electrically inclined, but this is my first time to even mess with a two stroke. The individual that had the bike before me had removed the lights and the bike even started without using the run/stop selector (it's been rigged). Are there online wiring diagrams for these? My best guess is that it's a '79ish model. I did find this link, but my symptoms are just a little different...

:help:

Thanks for any suggestions! :)

First thing you should do is get fresh gas and fresh two stroke oil. Premix it at 32:1 for now.

Disassemble and clean the carb out thoroughly with a good carb cleaner (keep that stuff away from the rubber parts). Poke a soft wire through all jet orifices and be very thorough. Ensure the throttle is not stuck, slide is in the right way, float height is correct and needle is in the right way.

If the problem still continues, ensure that the autolube line on the carb or mainfold is connected to the autolube pump and make sure you clean out the oil tank and renew the oil.

Worst case scenario: purchase 1mm gasket paper, replace the bottom end and manifold gaskets, anneal the copper head gasket and replace the magneto side crank seal. That should rule out an air leak.

Good luck. I had two of these and they're neat little bikes.

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