Does anyone know what year they used the finned rocker covers as in photo
Hi Peter - I don't think these are original equipment - rather some go faster parts of the day.
Happy to be corrected.
Regards - Paul.
The covers shown are almost certainly made by Paul Dunstall in 1960 or 1970. A similar version could also be purchased from Ian Kennedy. Both were based in London and after-market suppliers of race, cafe race and special parts for either tuning or enhancing the appearance of most Norton twins.
From 1948 until 1978 plus, the Norton twin rocker covers were identical and could be swopped between models. The only minor change coming in 1960/61 when the very first 650 Manxman engines had a special second breather arrangement as part of the inlet cover stud. This was hollow and vented out of a union held in position by the cover nut.
It was probably this single most important development that led to the Manxman becoming the best motorcycle that Norton ever manufactured...
Finned rocker covers are included in this 1969 Dunstall Catalogue:
Catalogue page 32, pdf file page 17.
As said, the finned caps were aftermarket items. I bought mine in 1965! Many thanks for the Dunstall Catalogue Andy!