1. Removing intake air flow restrictor
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.