1 is that the 4 Atlas headbolts near the sparkplugs are small, where the Commando are bigger.
And 2 is that Commando heads come in various RH numbers, with different compression ratios
and port sizes.
Before we delve any further into this, perhaps your reason for asking could be useful ?
Spigots on cylinders/heads where fitted to about the 1966/7 season, the 1965 model did have them, double speed oil pump were fitted from 1966 on, it was a common mod to fit these oil pump gears to earlier bikes.
What is less well known is that post 1966 the oil block and holes in the crankcase to the oil pump were increased in diameter, meaning that it was twice as likely to wet sump; don’t ask me how I know when I did this mod.
Sounds like carefully machining the spigots off the tops of the barrels will be necessary. Not sure, but you may need to obtain thin sleeves for the 4 main headbolt holes due the difference in diameter, or maybe that's not critical with all of the other hardware lining up?
The Access Norton Website uses cookies to keep you logged in if you register.
By continuing to use www.accessnorton.com, you are consenting to our use of cookies.