I am rebuilding the cylinder head of my 1959 ex Paul Smart 600cc Dommie but I am not sure what the valve springs should be although I have checked the main dealer websites (Andover/RGM/Norvil).
The Smart bike had been totally (professionally as far as I know) rebuilt less than 500 miles ago but it was leaking oil so I took the head off. Although the valve springs were changed during the rebuild I am still going to change them but there are variations in the sizes. The existing valve springs fitted vary in length, the outer springs from 49.7 to 53.0 mm (Haynes manual says 43.18 mm!) and the inner from 42.6 to 44.5 mm (manual says 38.9 mm!). I am concerned about the big differences in sizes between the springs fitted and that shown in the manual, RGM give spring sizes but those do not seem to tie up with what I have got. Thanks in anticipation. Ken
Hello again Ken - please…
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Hello again Ken - please remind me, has that PS bike got the semi-downdraught cylinder head or the usual pre-d/d 99SS big-valve head ? The d/d head has shorter but stronger valve springs than the previous head. Cheers, howard