The best way is to find a kit made for your moped. They will give you all of the parts you need along with a step by step manual. You could also have a dealer do it for you if it is to hard. But if you bore the bike out, you will probably want to gear the bike a little higher, so the extra power is used well. I would look for a kit to do this.
what determines when should bore and engine
The Bore of an engine is the tube that the piston goes up and down in.
std bore is 4.050
The Bore of a 350 cid engine is 4.00, the stroke is 3.48 inch..
4.000" the engine bore size
The bore size refers to the diameter of the cylinder in which the piston moves, not the piston itself. It is a critical specification in engine design, as it impacts the engine's displacement and performance. A larger bore typically allows for a bigger piston, which can increase an engine's power output.
yes
4"
Primarily the bore size. The 305 has a bore of 3.74 and the 350 is a 4.0 bore. They share the same stroke on the crank. And no, you can't bore a 305 to a 4.0 bore.
.7853x bore x bore x stroke x #of clyinders
I assume you mean engine displacement? To calculate engine displacement, use this formula: Bore x bore x stroke x .7854 x number of cylinders.
Engines are classified as small bore or large bore based on the diameter of their cylinders. Typically, a small bore engine has a cylinder diameter of less than 100 mm, while a large bore engine has a diameter greater than 100 mm. This classification affects the engine's performance characteristics, including power output, fuel efficiency, and torque characteristics, with large bore engines often providing higher power and torque at lower RPMs.