Having a motorized bike can be great fun. If you are looking to build a weed eater bike here are a few pointers to make your case simple-
How does it Work?
The whole process very simply involves installing a motor on your bicycle and powering your bicycle using the motive force generated by the motor. The motor is usually a 2-cycle variant and runs on a different fuel mixture that is not routinely available at all gas outlets. It is quite cost effective though.
The motor that you plan needs to be mounted suitably on your bicycle. For this you might have to weld the motor in place to the bicycle. Welding the motor directly is not a great idea. You will need to use metal straps to hold the motor and then weld these on to your bicycle.
Using Bicycle Motor Kits
An easier option is directly purchasing a motor that is specifically meant for powering bicycles. These will come with a proper attachment bracket and all you need to do is fit the attachment bracket over the rear wheel using the simple bolts provided with it.
Bicycle motor kits come in with a complete instruction manual and this can be very helpful if you have never done this before.
With a ready made motor kit all you need to do is take out the rear wheel, attach the provided ring (this is a large circular structure that can be easily mounted over the wheel) over the spokes and fit the wheel back the way you removed it. Next, you install the attachment bracket over the rear wheel and position the motor over it, fixing it with the provided bolts.
When this is done, you will need to simply put on the driving belt over the motor rotor and the ring you just fixed on the spokes and the assembly is complete. Lastly, you will need to complete the wiring circuit. These kits come with a throttle and engine kill switch that you can suitably attach on the bicycle handle bar with clips. You will need to attach wires from the motor to the throttle and the engine kill switch. While planting the wire make sure that it does not have any kinks and carefully tape it along the body of the bicycle to reach the throttle.
Your weed eater is now ready to use, after you pour in the fuel. The fuel generally used is gasoline that is mixed with lubricant oil. Having the correct proportion is important. You can create the exact fuel mixture on your own using a 1:1 ratio of gasoline with any good quality motor oil that is meant for use with a typical 2-cycle motor engine.
Motors are usually installed on bicycles as an aid to pedaling. However, you can also use custom motors of greater power to generate a good speed and thrust. Before you do this, it is recommended that you verify if this is allowed in your state, especially the limit of CCs you can have in the engine meant to be used for bicycles.