Two-strokes, cylinder heads and modern petrol

Modern fuel really isn’t targeted at strokers, and especially not when they’re in their sixth decade! It tends to burn significantly faster than period two-star and is infinitely less tolerant of basic ignition systems; it’s really only viable in vehicles with antiknock sensors and variable ignition timing. Although the AS1 head does feature a squish band unlike some contemporaries, what’s north of it may very well be less than ideal. There’s a very real possibility that the upper section of the bell-shaped combustion chamber may impart too high a compression ratio. This is then likely to promote detonation, which would harm piston longevity. Speaking to engineers highly skilled in the black art of two-stroke tuning and maintenance, we made need to take preventative action. Thankfully I know a man who can.