Tired of tuning and guessing, I mounted a O2 meter. It is fantastic, I can not take my eyes off it when driving. It gives very clear answers to my carb tuning. I will share a video and my tuning data here. Maybee it can help others.
What I have learned today is that the mixture screw doesnt affect the other circuits much (mostly engine braking and idle mix), and that the white spacer might be inserted again. My main jet was way to lean, and the cruising O2% was a bit rich and outside optimum.
Specs: Opened dyna muffler (app 40% light opening in the wall), home made angeled connection fro header-muffler, KN kone air filter
Mix Pilot Main Spacer
Carb settings 1/2 CCW 52,5 150 3 washers
Results o2%
Idle 10,50 %
Crusing 11 %
Engine braking when crusing 16 %
Half throttle 14-16% (Optimum)
3/4 throttle 18 %
Full throttle 20 %
Full throttle+ high rev Over 20% (out of range)
I think about trying bigger main and replace the white spacer.
Video:
https://vimeo.com/48299080