you need to get all the stuff the clutch side of that pedal shaft first.
38mph with a stock a35 top end and a hunter pipe is great. it's what I am getting out of a bike that i've built for a customer, GPS bike speedo verified. I'm geared at 26x22 on a 2.25" Mitas B8 tire.
I'm using a stock tomos cylinder head and the stock tomos airbox and intake and oil injection, too.
38mph is right where you should be. I would say get a stock a35 cylinder head and adjust your timing back to where it was and blast.
if you have a timing light and a dial gauge indicator, you could figure out exactly what your timing is set at, instead of just moving the stator. I'm like 99% sure that cdi will have a timing curve, which is pretty cool, but the only way you'll know is with a timing light!