Hello everyone, I thought it would be interesting to report the experience I had after replacing the original engine heads hemispherical dome with those produced by Ralf Schipmann.
I had evaluated the carburetion conditions observing the colour of the spark plugs after a few hundred km at variable speed, even without having carried out a real plug chop, the result was as shown in the attached photo.
After installing the engine heads, and after about 70 km I observed the colour of the spark plugs and the result was surprising, also considering that in the meantime I have not changed any carburetion settings.
The performance differences are in favour of the Schipmann heads as far as acceleration and rebound are concerned; I do not yet know the data of the possible variation in petrol consumption, however, the known surging problems remain. Now I have to correct the carburation, especially with regard to the very thin right cylinder; and here I would need the help of the experts of the site to whom I ask for advice to grease the carburation: increase the floating level (currently 23mm), tighten the air screw (currently 1+1/4), raise the needle clip (currently 2nd position) or?...? Thanks to all participants.