Upgrading 49cc flying horse 5G 4 stroke to a 79CC predator.

[Chippa]

I have the FH-5G-4Stroke:STD on my bicycle now, been running for over 2 years. Everything is fine.

I just need a we bit more power. I would like to drop in a Predatory 79cc from Harbor freight.

Can I just swap the motor out, or will I have to get a new Transmission? I seems like I can just get a new clutch flyweight, so that I can go from the tapered shaft to the straight shaft.

Does anyone know?

Thanks.
Chippa

 

[waynesdata]

I am working on a predator build now. The predator transmission is always listed alone. Do not think it will interchange.

 

[Chippa]

Did your predator engine come with dimensions for the screw hole mounts surrounding the output shaft?
I can't seem to find any dimensions on the internet, all I can find is pictures and screw hole sizes.

 

[Geordan White]

Hello ..I just did this same upgrade with my Onex 29er. I would definitely change the transmission. The transmission for my 49cc was completely different. I ha to change ... the engine mount, the engine and the transmission. And then I had to play with the gearing. I’m running the standard 79cc Gasbike CNC transmission with a 56 tooth CNC sprocket and adapter.. and this seems to get off the line good with little vibration and chattering.. but I also elected to change the spring in my centrifugal clutch from standard to a “ green spring “ engages at 2000-2200 rpm.. the standard spring engages at like 1800-2000 and I still had chattering off the line....so with all those changes... I have lots more torque and speed for sure.