Originally Posted by blee

You may try Picco no. 6 Turbo plug

I prefer Orion plugs:
ORI88825 CRF Turbo Plug No. 5 (Hot)
ORI88826 CRF Turbo Plug No. 6 (Medium)

For my experience, Picco engines need to have more head shims (from 0.5 to 0.7 mm, 16% nitro). You'd better try different shims thickness in order to get the best performance.