Short history, finished a 70cc A35 setup with Estoril. Up-jetted to I forget what. The thing pulled like mad at 45 and would hit 50. After moving the jet around trying to find the sweet spot, it never goes past 44.
This evening it's cool out. I start it and leave the drive, withing a 100 yards or so, I'm at 45 and thinking I shouldn't be pushing a cold engine so hard. But there is power past 45. It really feels good even a touch rich.
So the difference to prior trials is I'm blasting right up to top speed on a cold pipe. When the pipe gets some heat, I'm held back to about 44. What is going on here?