My nice little engine lives again after it sucked in a circlip through the cab a couple of years ago. It’s the best one I have built from scratch and sounds sweet and smooth. Fortunately no real damage was done but I had to strip it right down to check everything. One thing threw me for a while as no 1 cylinder was intermittent. Narrowed it down to ignition and checked from the coil outwards and got to the spark plug. The plugs are iridium and do not need adjusting but when I checked it there was no spark gap so the rogue circlip must have hit the plug closing the gap. Looks like the engine is headed for an Abarth replica.