This seems to be a never ending project but I have finally got my mini bike running smooth with no problems.
I started playing with motors about 3 years ago and attempted putting a motor on a bicycle frame. It worked, but not very well. I was forever having chain problems and it just sucked. I then found the web page minidoodle, and thats when it all started. Just over 1 year ago i got the opportunity to build a mini bike frame at school. I learnt many things throughout the construction process, the main thing being, never let people tell you it will wont work. Well I started looking at just about every minibike i could find, I ended up drawing about 3 sets of plans.
The original wheels were from a pocket rocket, which were excellent because they had disc brake setups. I had an old 4hp briggs that i could have used, but it smoked and wouldn't have lasted long. So after some research I chose to get a honda gx200 clone off ebay. If i were to buy another motor I would look into getting an old motorbike motor, mainly because they have inbuilt gearboxes.
So the first few pictures below are of the mini bike just after the frame was complete. The motor was box stock and it had a cheapy comet centrifugal clutch. At first i thought the motor had enormous power, but i soon got used to it. The rear sprocket soon ripped out of the hub because the pocket bike wheels are only made for 3-4hp motors. I ordered a new rear wheel setup which helped allot. From the beginning i always had chain problems, because of the length of the chain it stretched and rattled around lots from the motor vibrations, this caused the chain to frequently come off. I kept the bike in this setup up until about 1 month ago. I then decided to get the bike to work properly. I bought a comet 30 series torque converter and welded up a jackshaft. This shortened the length of the chain which fixed my chain problems.
Allong the way I have done some modifications to the motor. I have put on a gx160 head, 1.2:1 rockers and a 22mm mikuni carb. I plan on buying a good header soon.
Below are pictures of the bike in order from start to finish.
ENJOY
I started playing with motors about 3 years ago and attempted putting a motor on a bicycle frame. It worked, but not very well. I was forever having chain problems and it just sucked. I then found the web page minidoodle, and thats when it all started. Just over 1 year ago i got the opportunity to build a mini bike frame at school. I learnt many things throughout the construction process, the main thing being, never let people tell you it will wont work. Well I started looking at just about every minibike i could find, I ended up drawing about 3 sets of plans.
The original wheels were from a pocket rocket, which were excellent because they had disc brake setups. I had an old 4hp briggs that i could have used, but it smoked and wouldn't have lasted long. So after some research I chose to get a honda gx200 clone off ebay. If i were to buy another motor I would look into getting an old motorbike motor, mainly because they have inbuilt gearboxes.
So the first few pictures below are of the mini bike just after the frame was complete. The motor was box stock and it had a cheapy comet centrifugal clutch. At first i thought the motor had enormous power, but i soon got used to it. The rear sprocket soon ripped out of the hub because the pocket bike wheels are only made for 3-4hp motors. I ordered a new rear wheel setup which helped allot. From the beginning i always had chain problems, because of the length of the chain it stretched and rattled around lots from the motor vibrations, this caused the chain to frequently come off. I kept the bike in this setup up until about 1 month ago. I then decided to get the bike to work properly. I bought a comet 30 series torque converter and welded up a jackshaft. This shortened the length of the chain which fixed my chain problems.
Allong the way I have done some modifications to the motor. I have put on a gx160 head, 1.2:1 rockers and a 22mm mikuni carb. I plan on buying a good header soon.
Below are pictures of the bike in order from start to finish.
ENJOY
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