leeross Posted July 15, 2011 Share Posted July 15, 2011 when revs are dying down almost back to idle there is a knock/pop (metal to metal sound) coming from the head. Sounds as if the piston is hitting the head?! taken it all apart. Piston/Rings seem fine. No play in big end bearing. Slight play with small end bearing when you move it side to side but thats normal so im told. checled carb/exhaust all seem ok. When you rev, its revs up fine. Poping/knocking only hapens when revs dying down. i run 75ml castrol tts per 5 litres unleaded. Help. Quote Link to comment Share on other sites More sharing options...
leeross Posted July 16, 2011 Author Share Posted July 16, 2011 Problem solved. checked timing, cleaned carb, new plug, new (thick) base gasket, new head gasket - now runs like a dream!! Quote Link to comment Share on other sites More sharing options...
grib Posted August 1, 2011 Share Posted August 1, 2011 How thick was the new base gasket? My 240 makes this noise with normal unleaded petrol but seems better with Super unleaded, I'm not sure it's completely gone though. Quote Link to comment Share on other sites More sharing options...
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