Do I have performance issues or do i just expect to much?

I think that you are dealing with the limitations of the engine set up and the gearing. One thing you might try is looking at a "tuned "pipe. It effectively doubled my horsepower, But it set it up so that the power curve was a lot steeper.

Something else you might look at is the rear cog. I went with a 36 tooth. It requires more pedaling but it goes faster.

I went with a higher pressure tires with a smaller diameter cross section. Lower rolling resistance and less mass to get moving.

Lastly what I did was to try to get the body position lower and more like a road bike. The biggest amount of power once you get above 15 mph is the air drag. I dropped my handle bars by three inches and gained five miles an hour.

mike

I have a 48cc grubee angle fire with only slight mods. and get 31 to 32 on flats,with the stock 44 tooth sprocket. The only mods are cleaning up the intake and exhaust and matched them to the ports, sbp air filter and the muffler end cap extra exhaust tube. Main jet drilled to a #64. On mine the mid range is very good, when we ride as a group when climbing hill I can pull out and pass two others I ride with even though I out weigh both.