125cc lifan build


Local time
11:24 PM
May 19, 2023
Hey all! So i decided on my next winter project and have already ordered some stuff that i need. What im planning to do is to fit a Chinese Lifan 4 stroke 125cc engine into a bicycle frame. The reason for this is because i like quirky DIY projects and because i would want a bit more power then my 100cc china doll motor. The big addition would be the 4 gears which would allow me to climb a lot of the hills we have here.
I ordered a Lifan 125cc motor and another motorized bicycle kit (mostly for the hardware since no one ships the kits without engines to Slovenia... At least i will have a spare motor). Im planning on making my own exhaust out of some old scrap tubing. The bike im planning to use would be an older steel pony bike because they are small and have lots of room to mount the engine in the middle. I would reinforce the bike by welding a tube over the engine when it would be mounted. If not for that i could just find a nice large MTB or woman bike frame (they also have more room then an MTB) and use that...
I would probably have to offset the engine to the right so that the chain will run straight with the rear sprocket since i dont plan on using a jack shaft. Hardest part of this would be making strong engine mounts and mounting the engine straight and level because of the oiling system. Then just assemble the bike with the hardware i will take from the motorized bike kit and wire it up!
In the future im also planning to hook up a battery and lights since it has a built in generator coil for 12v stuff.
I have seen some people on the internet do it before and believe i can too. Put a 50cc sticker on the engine case to make it "legal" hehe....


New Member
Local time
5:24 PM
Aug 31, 2023
Sacramento, California
I think this is a very cool idea for the 125 on a bike, it would make a great mountain bike. However, if you are going to ride it on roads I recommend Maxxis hookworm tires, they are thick enough for good stability and can handle some loose gravel but shouldn't scrub you too much speed and acceleration.