I see you put a 30 series TAV on your souped-up HS40 engine. You also mentioned that it did not perform as well as you like. Did you originally use the 20 series Comet style driver and driven before. I heard the 10% overdrive of the 30 series can sometimes bog engines with additional load especially on large wheel bikes.
here is a setup on my fox thunderbolt and works great with this bike off road on trails. I still runs a cast steel flywheel so I don't get any unwanted vibration. not like some people are experiencing with using billet flywheels. just a good strong motor that pulls a easy 6000 rpm's. I like it a lot. pull the motor off that bike last year to use the cam and couple other things. building a new motor this summer with a stock steel cam with a compression release and going to install a set of 1.3 rockers ,22mm carb ,header,hot coil....etc and see how it does.