I have recently joined the club with a GT5 Super Rat on a cruiser frame. Myself and another forum member are having the same problem, or so it seems. Both our motors bog out at higher rpm's. Mine also seems to "load up" on fuel and you have to baby it up to speed a bit. I already put the spare head gasket on due to blow by gas, tried the spare spark plug, and brought my octane to at least 93 without ethanol, 25:1 mix. The only thing that seemed to help was the octane boost (NOS brand, full 6pt boost), it helped a bit with performance and reduced pinging a bit. The other member I mentioned said he tried another carb with the same results, I will soon try this to when I meet a buddy this weekend. I do wonder though if the main jet is just too big. I lowered the clip one notch to the middle, and it seemed a little worse. This leads me to think it might be the new built in CDI. Hopefully i can soon rule out the spark plug with a NGK this thursday, via autozone. Although I am still keeping the carb as the possible problem, I'm leaning towards poor ignition at high rpm's. Here's a great link to an ignition upgrade I want, not sure it will work with my ignition setup though. But I am awaiting a reply from the guy.
link:
CDI Ignition for the Chinese 48cc HT engine
link:
CDI Ignition for the Chinese 48cc HT engine
Last edited: