First off, every bike is different. The other thing is that a Shinko on the dyno will hurt you to the tune of 10-12 rear wheel horse. Consider that a Gen 2 with stock compression at 4 pounds of boost will make 220-230. A Gen 1 has lower stock compression, so you can expect it to make less. That is why Stage One kits for the Gen 1 will usually come with an 8 pound spring - good for 240-265 rear wheel, depending on the bike, the mileage, the tune (if it is a conservative tune with timing pulled, the number will be lower), and the tire you are using. Lastly, is that number SAE, STD, uncorrected?
Regardless, your mph does seem low, and you should look at your gearing and your clutch.