SM I have a 250 sidepipe engine in a later frame fitted with a PVL ignition,had no problems at all.Having said that I have a 380 still using points also no problems at all.I have read some material in the past with the opinion that the Femsa ignition is a "weak link".Make your ignition single plug and invest in an after market new electronic system such as PVL,friends who have CZs (and run at the front unlike me)have this setup.You can blank off the forward spark plug hole with a suitable bolt or just use a sparkplug.Cheers.