1961 Norton model 50 350cc
- Thread starter fireflake
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robs ss
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I'm not sure exactly what you mean by how engine numbers work - they are the same for all Nortons, the only difference with model 50s is the 13 prefix.
The numbers were used across all models - a reference is: http://www.norvilmotorcycle.co.uk/engrange.htm.
The items above the crankcase are interchangeable between the ES2 and Model 50 for the Featherbed (slimline) years - remembering that the Model 50 has 71mm stroke vs the 79mm stroke of the ES2.
It is reported that the cams for the Model 50 have more lift and longer duration than the ES2 but I can't confirm this.
The cylinder head for the Model 50 is more valuable as it offers more meat to create desirable squish.
The only caveat is the ES2 piston is heavier so the crankshaft requires attention to achieve the same (desired?) static balance factor.
Cheers
Rob
PS The ES2 noted below is really a bored Model 50 to achieve 500cc
The numbers were used across all models - a reference is: http://www.norvilmotorcycle.co.uk/engrange.htm.
The items above the crankcase are interchangeable between the ES2 and Model 50 for the Featherbed (slimline) years - remembering that the Model 50 has 71mm stroke vs the 79mm stroke of the ES2.
It is reported that the cams for the Model 50 have more lift and longer duration than the ES2 but I can't confirm this.
The cylinder head for the Model 50 is more valuable as it offers more meat to create desirable squish.
The only caveat is the ES2 piston is heavier so the crankshaft requires attention to achieve the same (desired?) static balance factor.
Cheers
Rob
PS The ES2 noted below is really a bored Model 50 to achieve 500cc
Thanks for that Rob, I was more interested in the engine # belonging to a 1962 rather than a 1961 model
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The barrels have same fixing stud spacing, so will fit, with possible enlarging of Crankcase mouth. See the 'pushrod performance' website , in the UK, for more info. Pete Ashley also did a site about his mods to a Model 50, also UK based.