RH 10 HEADS, ONE YEAR ONLY

Does anyone know why Norton made the 850cc heads with the smaller 30mm intake tracks for only one year? I belive this head is designated RH 10 only the 1974 Commandos were equiped with them. Prior to and after 1974 all 850 heads had the larger 32mm intake tracks.

Thanks,

Jason

Head Pages

Jason,

Dyno Dave has a good web page on some norton heads.

[Broken Link Removed]

I am not sure if it will answer your question but it is a good site for general info about the heads.

Thanks - and a nice web page it is. But it doesn't provide any clues as to why Norton made the RH 10 for only one year.

Jason

:arrow:

DynoDave,

I am no engineer but, maybe after the large porting on the combat heads, norton decided to go with smaller port sizes again.

Don't the "larger" ports in engine heads generally give more usable power in the higher rev range ?

And don't the "smaller" ported heads give more usable power in the low to mid-range ?

Your web page on Heads is a good thing and I am sure many others like myself appreciate the work you have shared with the world. I have often used it looking for information on norton heads, thank you.