Sounds like you're possibly running lean, deal with that soon. Burnt valves do not need to happen. With synced and properly jetted carbs, adjusted valves and the right sprocket ratio for your riding style, you may not need all these costly upgrades. 790 s have a hot cam to begin with, but a 904 kit with 10.5 to 1 pistons and you will definitely be able to go faster.
