The misfire or splutter is just over tickover, and it is till 2k revs, I have had the carbs apart 3 times, I have just ivanised the carbs which has made no difference. The misfire I mentioned was the spark plug wells full of water, I have fitted new plugs because of water in the plug holes, and the plugs starting to corrode, I know the plugs were not at fault, I did have an issue with no2 spark plug cap not sitting right but that is now slitting properly.