I hope Google translate doesn't mess this up but that thing desperately needs a carb sync with a set of vacuum gauges. I haven't worked on a V- Max since the 1980s but you should be getting around 148 BHP if the jetting is right and 210 bhp isn't too difficult with a few more modifications. If you want more than that fit a turbo or supercharger for around 450 bhp
Needs carburetor syncing, and if you have the stock air filter box from the vmax engine use that it will run better you need the air inlet restriction. The air filter box creates bit of under pressure that makes the the throttle open better and also it sucks in fuel better. I had the same issues with Honda engine. Else its good to see the progress.