Subject: Re: Tappet clearances - why the variation?
Quote by H 54 John:... the flaw in my assumptions is that the thermal regime is unchanged - it must be the case that the more mixture in, the bigger the bang and the more heat produced. So it will have been perfectly reasonable to play safe and increase the gap, thereby ensuring that the valve definitely closes under all circumstances...
Ah, but I think there is a flaw in this argument also - the instruction book gives a gap of .004 hot OR cold! So it may not be as susceptible to temperature variations as you imagine?