- The power on the project scooter is down a little, but it sounds good. The fact that it can idle without using the choke is a good sign that the seals aren't leaking.
- Note: Some suggest a test that you can do on the flywheel side. You can rock it back and forth and feel how much play is in the bearing. A little play is going to be normal because it's got to be able to move, but if it were real excessive that's a sign that the bearing is probably worn and it might require going into the engine.
- The modifications suggested include a new pump to increase the volume it puts out, a larger carburetor, a larger cylinder and a new performance exhaust.
- Slide the engine onto a stand, where the engine swing arms slip right onto the stand stud, and secure it with a bolt.
- Start by removing the old carburetor.
Carburetors are referred to with a millimeter dimension. The dimension is the size of the Venturi, where air and gasoline are mixed. The size of the project-scooter carburetor is 11mm, but it's going to be replaced with a 24mm carburetor.
- Remove the bolts that hold the carburetor in place.
- The carburetor is ready to come free from the engine and be replaced with the larger carburetor, which is going to give the scooter a boost in power.
Older carburetors get some wear around the slide and that creates a vacuum loss and cuts down on efficiency. When the engine has the ability to burn/use a larger amount of fuel there's a point where the stock carburetor must be re-jetted or replaced to allow more fuel and air into the engine cylinder.
- Place the new carburetor back on the engine, but before it's completely installed, hook up the throttle linkage. Tighten the threads putting light, even pressure to avoid cracking the casing or even the carburetor.
Any time you make changes to your scooter's engine, you must select the correct jets. Consult with the place you purchased your engine parts to get a recommendation on the correct jetting.