Does anyone knows what the balance factor of singles was when the
engines left the factory?
I have a1956Mod. 19 with a modified big end and the actual balance factor is 43%
I am going to re-balance the crank but I don?t want to drill too much so I can?t go back to
a original big end when that time comes
According to P L Garrat's book Norton Motorcycles (he worked at Norton's) the balance factor for the Mod. 19 is 50%. My ES2 runs at this balance factor and is pretty smooth.