Engine Trouble GT90 Conversion Kit Won't Start

[Phabbits]

One thing I noticed on the gt90 is that it has a windowed piston and trench port that are not needed for a case reed.You may want to try a reg (non windowed) piston also make sure that the piston crown doesn't come down below the intake at all.

That's very interesting, I thought that the window was necessary for the fuel to reach the top of the piston, after a little research I see that's not true. So I should make sure that piston crown never goes below the intake, it will need to use the slot in the cylinder then right, I forget exactly where that slot was.

with piston at top, check that rotor of mag has its key slot at about 1 o'clock and the flats in the rotor are about level with the ground

Now that's a great tip, when you refer to the rotor, that would be for the magneto right? So have the non-rounded sides level to the ground?

This is really helpful information guys, thank-you so much! I think I might create a document to help beginners like me on how to set up the GT90.

 

[Tyler6357]

As I understand it, the windowed piston are only required if the reed valve is connected to the cylinder intake but for a case reed valve like you've got it is not necessary. Ummmmmm, I think that's how it is. Also, I agree with Crassius, 1 o'clock for the rotor mag key at top dead center for the timing.

 

[Phabbits]

Thanks for all the advice!

Hopefully I will be able to try all these things out next week, and get 'er going.

 

[Phabbits]

Just for closure on this thread, I finally had time to go back to this bike and try to get it working, two years later. I had to replace a rear flat innertube, and a broken plastic throttle, which should have no affect on the starting of the bike I believe, before attempting to start. I then tried to start the motor and it started! I ran it for about a minute with the choke on, and then I could turn the choke off. I have not had any issues starting it since.

 

[Wrench]

Just for closure on this thread, I finally had time to go back to this bike and try to get it working, two years later. I had to replace a rear flat innertube, and a broken plastic throttle, which should have no affect on the starting of the bike I believe, before attempting to start. I then tried to start the motor and it started! I ran it for about a minute with the choke on, and then I could turn the choke off. I have not had any issues starting it since.

Who ever thunk by fixing the throttle the bike would start

 

[Frackerboy]

You got your fuel line on the wrong connector!!

 

[FatherMoonMan]

im not familiar with ur exact carb but if its anything like mine where its either fully open or fully closed then that could be ur problem, if its closed and you cant figure out how to open it again try giving full throttle and at the same time pressing down on the little arm.

 

[DAMIEN1307]

You got your fuel line on the wrong connector!!

im not familiar with ur exact carb but if its anything like mine where its either fully open or fully closed then that could be ur problem, if its closed and you cant figure out how to open it again try giving full throttle and at the same time pressing down on the little arm.

You guys both know that the chances of a reply to your statements here are between zero and none, RIGHT ???...lol...The thread your on started in Feb of 2018 and last reply was a year ago and Phabbits hasn't been seen on the forums since June 26th 2020...lol...However, welcome to the forums anyways...DAMIEN

Ps...FatherMoonMan...You have had quite a few replies to your first thread posting in May 15th 2021...You might want to re-visit that thread to tell us your progress.

 

[FatherMoonMan]

You guys both know that the chances of a reply to your statements here are between zero and none, RIGHT ???...lol...The thread your on started in Feb of 2018 and last reply was a year ago and Phabbits hasn't been seen on the forums since June 26th 2020...lol...However, welcome to the forums anyways...DAMIEN

Ps...FatherMoonMan...You have had quite a few replies to your first thread posting in May 15th 2021...You might want to re-visit that thread to tell us your progress.

i could have sworn i replied to the thread, but i guess i got caught up with school and forgot to

 

[Phabbits]

Hey All!

Thanks for the further advice! Although the engine does start, it still has a large air leak issue: I need to keep the throttle open to keep the engine alive and even then it runs rough and quits unexpectedly. It has been a while since I tested with soapy water to find where the air is coming in from, but I will try that again soon.