1. Removing intake air flow restrictor

This is the 2010-later carb, with red silicone over idle mixture screw. The PHVA14 has an idle speed screw, with a big knob sticking out for the rider to use occasionally, and a idle mixture screw, recessed with a slot head, for the service technician to use.

The “elephant trunk” restrictor is exposed, a hidden part of the junction sleeve 233748 that joins the air filter/silencer to the carburetor.
2. Replacing the rear sprocket
Sprint, ST and LX models come with 28 tooth. Replace that with 22 tooth and subtract 3 chain links.
Revival and Streetmate models come with 31 tooth. Replace that with 24 tooth and subtract 4 links.
3. Shortening the stock exhaust
Only welders and metal workers can do this. But the benefits are huge. Speed increase from 37 to 43 mph.