There's room for improvement everywhere on any build. Best to start with the basics and tune what you have and when the limitations are found change parts but until then persevere with what you already have. A lot can be improved with just advance curve work (timing) and carb (fuel)
What spark plugs are you using and what gaps are they set at.
How do they look?
Does it hesitate or bog or run rough anywhere in the RPM range?
What fuel?
Forget about spending any money first make sure you have the basics ironed out (Air Fuel Ignition) before grabbing the wallet.
