Small two-wheeled scooters powered by kicking have become popular among kids. For older, more responsible riders, more expensive scooters with gas motors are available. If you want to build your own gas-powered scooter, the motor from a chainsaw will do the job for you.
Get a small two-wheeled scooter. A generic children's scooter from toy store won't do, however, especially if you plan to take the scooter off-road. You need to find one with inflatable wheels and hand brakes because these can handle rougher surfaces and are easier to stop.
Remove the chain and bar from a gas-powered chainsaw. You should leave the rest of the chainsaw together, as keeping the motor inside the housing will make it easier to mount onto the scooter.
Decide how you will connect a bicycle or similar chain to the chainsaw's crankshaft using a sprocket. The crankshaft is what the bar and chain were connected to. If you want to remove the centrifugal clutch (the round dish-like device connected to the crankshaft) to make this easier, do it now. You can also keep the clutch on if you can attach the sprocket to the clutch bell and put the chain on there.
Bolt one sprocket onto the crankshaft/clutch and another one onto the scooter's rear axle. Depending on the type of scooter, you may need to modify the rear wheel mount before doing this.
Place the chainsaw motor on the scooter's riding platform. Make sure it's in a place where the sprockets are in line with one another so the chain won't drag against the scooter's edge. Drill a hole into the platform and the motor housing and bolt them together.
Connect the chain to the sprockets. You will probably need to remove some of the chain links with an extractor tool so the chain will wrap tightly around the sprockets.
Install a dirt bike hand accelerator to one of the scooter's handlebars. Wire this accelerator to the motor's on/off wires. The hand accelerator should be able to control the power to the engine.
A chain or gear guard will help protect you while riding. Attaching one can prevent anything from getting caught in the chain while riding.
There will be problems with using the motor without its centrifugal clutch. You'll need to lift the rear wheel off the ground to start it up. If you're using a two-stroke motor, you can also risk burning out the motor because the clutch helps add a fuel-oil mixture to lubricate everything. Consult a hardware expert on the safest place to drill a hole in the chainsaw motor housing. This is especially true if the housing is plastic. If you put the hole in the wrong place, or use the wrong size washer with the bolt, the bolt will rip through the housing while riding.