Time to retire the 50cc Polini Gr2 Nikasil version. It needs a full service, piston ring, maybe piston, gaskets, variator.
This kit was as powerful as any Bidalot 50cc engine in the straight.
Too bad it's discontinued...
Super reliable race after race @12,500 rpm all day... using my favorite and cheapo stock motobecane cdi ignition which I put to the test against the MVT premium external rotor, then against the HPI internal rotor advanced timing... the motobecane smashed them both throughout the entire range.
The Moryama is a reference, such a simple but powerful ignition unit designed by the Japanese way back. I use it on all my setups under 13,000 rpms.