1971 Cylinder head nuts

rob carter · Sep 6, 2016

I need to tighten the cylinder head nuts on my 1971 commando.I have located 8 of them but cant find the two centre ones.Are they accessed through the rocker coers.
Any help would be appreciated Rob Western Australia

lcrken · Sep 6, 2016

There are only 5 cylinder head nuts. Two on the top at the front, down in the wells in the fins, and three on the bottom. There are also 5 cap screws (bolts) on top, 2 on each side and one in the center.

I think you might be looking for the two at the front. You will see two circular holes in the top fins just in front of the exhaust rocker covers, and close to the center line of the engine. Down in the bottom of those wells are two more nuts.

Ken

rob carter · Sep 6, 2016

thanks Ken the ones i am looking for are 1 and 2 in the workshop manual which are between the cylinders
Rob

Rohan · Sep 7, 2016

No 1 is down a deep dark hole coming in from above towards the front of the cylinder head.
Near the top iso brackets.

No 2 is accessed from underneath, and is accessed through the fins at the top back of the CYLINDER,
travelling upwards into a short deep black hole.

Bert Hopwood must have spent ages figuring out how and where to put those pair there, all Norton twins are the same layout - more or less.
Hopethishelps.

rob carter · Sep 7, 2016

Thats great thank you so much i have been racking my brains to figure it out

Rob

rob carter · Sep 7, 2016

I managed to find all the nuts and bolts,i found that all my spanners did not fit exactly and i will require whitworth ones.I also noticed that the one round the back has a special spanner made for it which is a ring spanner.
My question is how on earth can you tighten up them all with a torque wrench.

Rob

pommie john · Sep 7, 2016

People do make adaptors so you can torque them all properly, but I have always used a torque wrench on all the top facing ones ( you need a deep thin walled socket for the front three) but I just guess at the lower facing ones. Never been a problem for me.

bluto · Sep 7, 2016

rob carter said:
I managed to find all the nuts and bolts,i found that all my spanners did not fit exactly and i will require whitworth ones.I also noticed that the one round the back has a special spanner made for it which is a ring spanner.
My question is how on earth can you tighten up them all with a torque wrench.

Rob

I used this makeshift arrangement ( a 3/8 hex bit on the torque wrench driving a 3/8-7/16 combo wrench) to torque nuts # 7 and 8, worked fine...anyway an important thing I learned is that if the adapter is at 90 degrees like in the photo no torque correction is required.

rob carter · Sep 8, 2016

Thanks for the replies.Looks like a tool company could make some money out of this.

lcrken · Sep 8, 2016

This is a short extension I made to torque the nuts on the head studs. It's just a cut off wrench welded to a spare socket. It's 3" long on centers, so I set the torque wrench to 4/5 the normal torque spec. It's for 7/16" hex to fit the reduced hex nuts I use, like the one shown next to it, as well as the later 850 style long nuts. If you are using the larger hex stock nuts, it would be pretty simple to make a similar extension in the correct size. Included in the picture is wrench I bought back in the '70s that is purpose specific for tightening the nut at the rear of the head. The outside of the box wrench has been ground down for clearance in the head.