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Jul 20, 2004
Thanks for your patience w/ a newbie.
With a project restoration starting , I wonder:
1. Do I need Whitworth tools for a 74 Commando JPN ?
2. Where is a good source in U.S. for Whitworth wrenches/sockets ?

If you are going to eat an elephant , you gotta do it a bite at a time.
Commandos are a mixed breed. All the chassis parts are SAE thread fasteners. This makes it much simpler to replace the rusty old cad plated fastener with bright new stainless steel. However, the engine and transmission still use CEI (26 TPI) thread form and require whitworth wrenches and sockets.
I have acquired alot of whitworth sockets over the last thirty years, and have a mixture of Craftsman (no longer made), Snap-on, Brit-Tool, and Japanese Koko (sp?). I find the Snap-on are often too thick in the walls and won't fit in tight places (and outrageously expensive). As a result, I find myself grabbing the Japanese sockets most often. These are fairly good quality and I have only broken one. They are available thru most Brit Bike dealers such as Jim Bernier, Rabers, and others.
As far as wrenches, the Spanish made set of combination wrenches is probably the most versatile. They also are available from Brit Bike dealers.
The only specialty wrench necessary is the thin-wall ring spanner for under the exhaust ports and the cylinder head nut under the carburetors between the cylinders. This is usually sold as a two ended ring spanner curved like the old "starter/generator" wrenches mechanics carried.

I ditto Ron's disussion on SAE and Whitwoth fasteners. Acessa is the Spanish company that makes Whitworth wrenches, which are available at Gulf Coast BMW/Triumph. This dealership also carries Kolo Whitworth sockets. Please let me know when you are going to Gulf Coast BMW, as I would love to meet with you and see your bike.

Also, you can grind down an Acessa box end wrench to acess the rear cylinder head nut that Ron talks about. I've done this with great success.


While on the subject, there are four important "special" tools needed to work on Commandos.

1 - A clutch spring compressor. These are easy to come by, or if you are resourceful you can make one from a kitchen sink drain basket and a bolt with two nuts.

2 - An exhaust rose wrench. Again the "proper" tool is available, but check the the local flea market for an old-time plumber's "spud" wrench. I even have a small version which fits perfectly in my tool wrap.

3 - A rocker shaft extractor. A proper size bolt and a deep well socket will suffice, but finding the tool is often easier than finding a bolt long enough.

4 - The only one I have yet to find a shade-tree substitute. The three-jawed pinion gear extractor for the crank shaft.

Any other favorite "special" tools??
In additon to the special tools that Ron mentions, I recommend a pin spanner for that dioblical lock ring on the rear wheel. Also, perhaps a Rowe spoke wrench for the wheel spokes and a skinny wrench to fit the hex on the crankcase sump filter. Lastly, you will need a large (1.25" approx.) socket for the fork cap nuts. Oh, and I almost forgot, some valve guide drifts are real handy, especially for installing the new guides.

Having said the above, you could probably make-do with some other tool or device; it just makes the job easier and prevents unsightly damage if you have the special tools.

But, whatever you do, don't try to pry off the timing pinion gear with screw drivers. You should use the three-jaw puller that Ron mentioned, item 4 on the list.

The skinny wrench for the sump filter may not be required for a '74 Commando. I know that early Commando frames contained a cross-brace directly below the sump filter, which precluded the use of a socket to remove the filter. Only a skinny box-end wrench would work. However, the cross-brace on the '74 frame may have been relocated to avoid this problem.
Good points, Jason.
I found a universal disc grinder pin wrench that has one swinging pin that wil adjust to fit the bearing retainer rings on both the front disc hub and rear MkIII disc hub.
The fork top nuts are 1-5/16". The same wrench will also fit the lower steering head nut on '71-on bikes.
While on the topic of large wrenches/sockets, a 1-1/2" (very) deep socket is required to remove the transmission sprocket retaining nut. The proper wrench for the larger engine sump plug is very handy. I forget the size but I picked one up from Sterling Motorworks that works very nicely. I think that most Norton parts suppliers carry the same one.


I made a pin wrench for the wheel bearing retainer and the disc brake end plug from a piece of strap iron with two holes drilled in it. I then pressed two hardened pins (automotive drum brake shoe return spring pins) in the proper holes.

Thanks for all the info. I will start buying some new tools.
A man can never have too many tools or guns. :mrgreen:
Speaking of tools -

Due to a recent bolt snapping incident during a brake rotor swap on my Mazda... I am in the market for a new torque wrench.
I have an old beam version that does not inspire confidence.

Given Norton's heavy vibes - I figure proper torque values and a drop of Locktite are a must.
Does anyone have any thoughts on the merits of one type or brand, cost vs performance. etc


If designed and assembled properly, the beam-type torque wrench is the most accurate. Clicker-type torque wrenches have several moving parts that can become worn, damaged or mis-adjusted. Any one of these problems will cause inaccurate torque readings.

However, the beauty of a clicker is that you don't have to be looking at the scale while torquing. You simply set the torque and pull the wrench until you feel it click.

In contrast, the beam-type wrench demands that you keep a steady eye on the scale while torquing, which is not always easy to do. I have three Craftsman torque wrenches: a beam-type (0-100 ft-lbs), a clicker (0-20 ft-lbs) and another clicker (0-150 ft-lbs). I use the beam-type torque wrench to verify the accuracy of the clicker wrenches.

I hope this helps.

One beauty of the beam style torque wrench is that if you are torquing a fastener that is about to snap or strip, you will get some warning. I was recently torquing a clutch pressure plate on a tractor and I had a bolt that was truning but the torque was not increasing. I was lucky in that I realized what was happening ( the bolt was yielding) before the inevitable happened. The bolt was removed, a new one installed and blessings were counted.

Thanks guys -

It seems my old beam is not that bad after all - how often is the basic cheapo option just as good as the pricey one.
I think I will pick up a clicker and cross reference the two as Jason suggested. In my case the clicker style should rule out some operator error.

I found some interesting info -
Torque Wrenches- How Good Are They?

Thanks again for the input,

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OK, very good class, but nobody mentioned the tool to hold the clutch basket to keep it from turning. Make one from two old clutch plates, one steel and one fibre/bronze, riveted together and bolted to a suitable handle. Automobile water pump pulleys make very good clutch spring removal tools.
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