Torque setting

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mrlsi

mrlsi

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good afternoon all , is there a torque setting for the 4 through bolts , barrells to crank case , carnt see one in the service book. 1975 850mk3 , thank you in advance
 
Torque setting
 
Gtiller: (or anyone)
I'd like to see a chart showing what wrench sizes are required for each of the head bolts. Particularly for the MK3.
Got anything?
Jaydee
 
1/4 Whitworth for the bolts and nuts from the top and the #2 nut at the rear. The hex studs at the front bottom should be 7/16" (or maybe 3/16 Whit which is close). That's for a MKII, if it changed for the MKIII I'm sure LAB will correct me.
 
I have just updated the Cylinder Base graphics to include spanner sizes.

I have based this on the hardware on the Andover parts diagrams, so I'd appreciate it if someone can confirm them for me:
  • pre-1972 750 (and older bikes like the Atlas)
  • post-1972 750 (Combat onwards)
  • 850 (with the through bolts, which will cover the Maney barrels too)

Hope this helps!
 
I also bought a new stronger 750ccm barrel with 850` design and through bolts.
Do you use some Loctite or other stuff for this 4 throughbolts? me just thinking when you don`t reach them after the cylinderhead is installed.......
 
gtiller said:
  • pre-1972 750 (and older bikes like the Atlas)
  • post-1972 750 (Combat onwards)
  • 850 (with the through bolts, which will cover the Maney barrels too)
Click to expand...

The update has deleted the links.
However...
granttiller.com

Norton Commando Cylinder Head Tightening Order and Torque

This graphic shows the best tightening order and required torque settings for the Cylinder Head on a Norton Commando 750 and 850
granttiller.com granttiller.com
...the spanner (socket) size for 'J' and 'B' is 1/4WW.
'I' and 'C' (the sleeve nuts) was 1/4WW early, and 3/16WW (or 7/16 AF) late.


Wouldn't it be simpler to mark each fastener with a letter in order of tightening so the sequence would be A-J, not A,F,H,E, etc. but why use letters when numbers are normally used and are easier to follow?

Twin Cylinder Head Tightening (2) | Norton Owners Club

www.nortonownersclub.org www.nortonownersclub.org
Torque setting
 
Last edited:
Thanks Les,

The Andover head fasteners kit is described as:

06.7097​
CYLINDER HEAD FASTENINGS KIT 750 & 850 (FROM ENGINE 122436)​

I put engine number 122436 down as pre-Commando, so had assumed that the same sleeve nut was used right through Commando production?


The links are still there in post #7 - they haven't changed.


I used letters based on the Old Britts tightening sequences, which is what I have always used.
I am happy to change them to numbers if that's what people would prefer to see?
 
The factory service manual shows them as numbered, and that's how they're usually referred to. Everybody knows what the "Number 2" nut is.
 
Last edited:
gtiller said:
06.7097CYLINDER HEAD FASTENINGS KIT 750 & 850 (FROM ENGINE 122436)
I put engine number 122436 down as pre-Commando, so had assumed that the same sleeve nut was used right through Commando production?
Click to expand...

"From engine 122436" I'd guess was when the head bolts changed from 5/16" to 3/8".

The parts books list sleeve nut NM24260 to 1972 which has a 1/4"W hexagon...
www.rgmnorton.co.uk

CYLINDER HEAD SLEEVE NUT

USED ON ALL 750 ENGINES, 3/8" X 26TPI THREAD. FITS THE TWO FRONT STUDS LOCATED IN THE CYLINDER HEAD. 1/4" WHIT SPANNER SIZE. LSO SEE 063192S FOR
www.rgmnorton.co.uk

...063192 '73-on with reduced hexagon and which supersedes NM24260 which is why 063192 sleeve nuts are included in the kit...
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

...therefore what is now 7 & 8, the hexagon/spanner size can be 1/4"WW or 3/16"WW (7/16" AF which is a better fit in my opinion).
 
Thanks Les - I have added a note on the drawing, since that seems to be the only change to the head during the life of the Commando
(and one I knew nothing about!)

Esme - thank you! I have numbered them now, so everything is covered (I think)

Thanks all!
 
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