Can Anyone Identify This Norton Head?

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arch

arch

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I am still trying to figure out how to post pictures so I will have to just describe the Norton head.

The oil lines attach in the side of the head like a Commando.

It has 28mm intake ports

There is the number “4” (not RH4) stamped on the head, near the center not near an exhaust cover

The intake valves are the same size as those on my RH 10 Head. I didn’t check the exhaust valves.

Any ideas?
 
Sounds like a '68-'71 750 Commando head. I don't know why it is stamped with a "4" though. Might not have been done at the factory.
 
arch said:
I am still trying to figure out how to post pictures so I will have to just describe the Norton head.

The oil lines attach in the side of the head like a Commando.

It has 28mm intake ports

There is the number “4” (not RH4) stamped on the head, near the center not near an exhaust cover

The intake valves are the same size as those on my RH 10 Head. I didn’t check the exhaust valves.

Any ideas?
Click to expand...
Have a look at Dyno Daves site atlanticgreen.com has a good write up on heads and how to differentiate the type.
 
I think Ron L nailed it.

I did check out Dyno Dave’s website but didn’t see anything in his chart that matched.

After Ron’s post I looked further and did find more info that described this head on Dave’s website.

My bad

Thanks for the replies!
 
arch said:
I am still trying to figure out how to post pictures so I will have to just describe the Norton head.

The oil lines attach in the side of the head like a Commando.

It has 28mm intake ports

There is the number “4” (not RH4) stamped on the head, near the center not near an exhaust cover

The intake valves are the same size as those on my RH 10 Head. I didn’t check the exhaust valves.

Any ideas?
Click to expand...
RM 1?
 
nailed it?
Heads RH1 are 68-70 then 71-72 core (besides port size) are a bit different.
Pix of bottm and of side picket fence tells all.
 
dynodave said:
nailed it?
Heads RH1 are 68-70 then 71-72 core (besides port size) are a bit different.
Pix of bottm and of side picket fence tells all.
Click to expand...
sorry RH1 ...mine is an RH1 head supplied on a late 71 bike bought new.
 
oldmikew said:
sorry RH1 ...mine is an RH1 head supplied on a late 71 bike bought new.
Click to expand...
Typo RH or RM is not the issue presented on my site. It is that there is an early RH1 AND a late RH1 for those interested in knowing how to tell them apart. Not 100% but generally follows 20M3 early and 20M3S + 72 is later RH1. Combats use the later core for big port 750.
 
Here are pictures of the head in question’
 

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Definite early RH1. Early picket fence pattern between rockers, 28.5mm ports. Nice head
06-0380 # sticks out "positive", late is sunk into surface "negative".
4 adds nothing
all 750/850 commando heads have the same size valves.
early small bolt patterns heads have .1" smaller intakes
 
I do not remember the Burco logo , but its a long time since the head was off. This presumably was the foundary insignia, maybe when Nortons moved from the old AMC factory at Plumstead to Andover they changed suppliers?
 
Isn't that the oval BIRCO logo also on the back of all 750 and 850 barrels. 62-75?
 
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