M6 odd rev issue

I recently bought a 2010 M6 and can't seem to figure out what's wrong with the thing. It idles fine and the mid range seems good but it won't open up and rev. The max I can get it to do is 7400 with full movement of the powervalves. I'm not sure if it makes a difference or not but the low beams do not work on the sled.

Here is what I have tried. A local dealer had an 09 so we tried the ECU and that didn't change it. I also checked the reeds and they are good. compression is 125 per cylinder. switched throttle bodies with the other sled (TPS and all) still nothing. Tore down the harness and started checking wires and can't come up with anything. Replaced stator due to charge coil 2 only showing 5.2 ohms. I also unplugged the handle bar harness with no luck. When the handlebar harness is plugged in and I hold the throttle in the idle position to rev it it seems to run the cleanest. I have also swapped the tank from my good running M7 and it didn't change anything. I am unsure of what route to go down next. any input would be greatly appreciated!

Here is a link to what it is doing currently. I also tried holding the exhaust valves open with no change.
https://www.youtube.com/watch?v=QwO_tbzym54

still no fix...

I have tried many servo motors and have not checked the clutch. But I would think I would get the revs without the belt on then. the sled has 6k miles on it I'm starting to question top end/ crank seals maybe?

Compression is 110pto 115 mag. crank seals seem fine I have done the spray brake clean around them test several times. I'll give another primary a try. Rode it again today and only got 64-6500 rpm. getting very frustrating!!!!