Friday, 15 July 2016

When is a Norton not a Norton ...

-SG- ...when it's a Scott! In the late fifties and early sixties, and before the VMCC in UK was organizing its own race meetings, we had to rely on the goodwill of other organizing clubs to include a Vintage class in their race programs. None the less, the VMCC had a set of rules by which would-be racers had to abide, which basically forbade use of any post 1930 (visible) parts. Those who appeared with later bits and pieces fitted were allowed to ride but were warned that if they finished well up, they would be excluded from the results! Strangely, in some ways, it was permissable to use dual braking on the front wheel.

Bob Collett, who started racing in the late fifties on a Model 18 with rather dubious handling, hit on the idea of installing a Vintage Norton engine in a 1929 Scott frame, and having checked with the VMCC hierarchy that it would be allowed, the plan went ahead. His Scott - Norton appeared on the scene in 1962 and was a great success in Bob's capable hands, and later, those of Steve Lindsdell.

Bob still owns the bike and he/it appeared at the recent Cadwell Park meeting - looking, and sounding, just as I remember it. I have been promised a sheaf of photos of the bike but for the time being those attached will have to suffice. The engine incidentally is a mid 1930 ES2 unit while the period LS gearbox has a neat positive stop footchage mounted on the back of the casting - no room to put it anywhere else. During its racing years it was run on methanol but is now set up for petrol with a type 29 Amal.

Friday, 8 July 2016

Jimmy Shaw's 1921 works bike

-SG- Most visitors to the site know of Jimmy Shaw, the Belfast dealer who, for most of the twenties, was a member of the Norton works team. His best TT placing was 4th in 1927 but his efforts in the Ulster were I think, considerably better. To my mind, probably the most interesting Norton at the recent VMCC Banbury Run was actually Jimmy's 1921 mount, on which he unfortunately retired.

The present owner checked out the frame and engine numbers with the DVLA and naturally was very pleased to find they were correct for the Norton with reg. no. OH7083.  Attached are a couple of early photos  as well as some kindly taken by Alan at Banbury. Incidentally the forks still have lugs for the cycle type stirrup front brake but a 'powerful' internal expanding unit was used for competition.

Wednesday, 6 July 2016

Moore CS1 Production Figures

-SG- I had a message the other day from a CS1-owning friend in Northern Ireland, asking if I knew how many of these machines were made (I refuse to call them 'cricket-bat' models - a journalistic invention from the post-war era!). I checked this out some years back but had forgotten the quite large total involved of around 1135, from late 1927 to early 1930. There were of course a few works ones also produced earlier in '27 for the TT etc. which are not listed in the records, whereas the 1928 works machines are included.

Wednesday, 29 June 2016

1926 Model 19 Norton

Brian in the UK sent us these pics of his 1926 Model 19 Norton. Brian: "I thought you may be interested to see my Norton. The front forks are interesting, perhaps somebody upgraded Nortons in the late 20’s as several seem to have been converted. The fork fittings are all chrome plated, which would indicate a later date. The engine, gearbox, frame, magneto and petrol tank match the factory records. I have the original mudguards which are usable but would need work."

-SG- As regards to the forks, these would have been fitted later, as you correctly surmise. The patent application for the Druid Enclosed Spring design was made in 1926 and by the TT of 1927 a very few bikes were fitted with them for the event (not Nortons). Nortons did fit them as standard to the CJ and JE models later in the decade and there are a few machines listed in the records as having the larger size fitted from new and a very few with the braced variety which you have. This type was intended to appeal to side car users and perhaps your bike had one attached at some time. I suspect Druids paid a higher bonus to sporting users of their forks in the early thirties as both Pat Driscoll and Bill Lacey used them on their Brooklands mounts, in preference to Webbs.

Tuesday, 21 June 2016

Sturmey Archer lever - and John Bull products

-SG- Back in 1931 my good friend Jack Bindley went to the Isle of Man for the third time - I think on one of the special trips TT trips then available at a special price from 'Motor Cycling.' He was given a small booklet published by the Leicester Rubber Company - aka John Bull - containing the names of the riders and other useful TT information, plus of course details of John Bull's range of products at the time. Apart from tyres, one of the products we are all familiar with is the George Dance knee grip, fitted to virtually all Vintage machines with sporting pretensions. But one of their other accessories was a rubber boot to fit onto a Sturmey Archer gear change lever of the twenties type - or, for that matter, any gear lever with a knob of about the same size.  By sheer co-incidence I received the photo attached the other day - showing a new Sturmey lever complete with rubber boot which a friend of mine has just acquired. Hate to think what it cost! Anyway, this prompted me to unearth Jack's 1931 booklet and scans of it are also attached - click this link. Incidentally I know of just two other of these rubber boots to have survived - one in NZ and one in Northern Ireland and both on Nortons - but there are doubtless others out there somewhere, some more perished than others!

Thursday, 16 June 2016

1935 MGP - Dr J K Swanston

-SG- Dr Swanston - who died a year or two back at over 100 years old - told the story of his 1935 MGP win in his contribution to the History of the Manx Grand Prix 1923 - 1998.  Co-author Bill Snelling has kindly given permisssion to reproduce Dr Swanston's article and this is attached (below).

It is interesting to note that, despite all the fuss over amateur status which caused the demise of the Amateur TT and the start of the Manx GP, six years earlier, Dr Swanston relates the substantial help he had from the works during his racing activities - and all for the sum of £10 ... almost a case of 'plus ça change, plus c'est la même chose'.

One of Dr Swanston's earlier bikes - I think his rather special 1931 Senior mount - has survived and has been restored.

'Ctrl-right-click' and 'open in new window'
for a large version

Thursday, 9 June 2016

Tuning the WD16H Norton

By Paul Greet in New Zealand

This shows the areas in yellow where the head is relieved
next to the valves. There is an interesting impingement
shown by the exhaust flow witness over the ridge between
 the cylinder and valves. Worth getting rid of, probably.


The humble WD 16H Norton is one of the least pretentious of motorcycles. In standard form, it is slow enough to make riding on the roads awkward. However, it can be upgraded, quickly and simply, at low cost. With the suggested modifications, it will have much better torque, a cruising speed of 60mph and above, and a top speed of 80mph. 70mph can be maintained for long periods without undue drama. The standard appearance is retained, except for the exhaust. The standard cams are also retained.

The modifications take advantage of the fact that Norton knew their way around sidevalve engines very well indeed - no Ricardo patent needed for Norton; they already had the pop-up piston giving the potential for a good breathing/compression ratio balance vital to a sidevalve.

No originality is claimed for any of these modifications: all have been copied from other work and other modified motorcycles. A good source is anything written on the racing Harley Davidson WR45 - these sidevalve engines were heavily developed. Quite a lot of on-line information is available for these engines.


There is no point in attempting any of the modifications described unless the engine, gearbox, forks, brakes and cycleparts are in good order. As the bike will be faster, it needs to be in good condition.


The standard carb is 1 inch. Change this for a 1 1/16 inch as per Model 18, along with the Model 18 inlet stub. This makes the inlet tract parallel, not ideal, but better than expanding from the carb onwards, as standard.

This photo shows the area on the deck, and around the
recessed inlet valve, to be relieved. Also the area of the 
cylinder rounded off.


Stainless steel racing valves intended for Chevrolet V8 engines can be bought at reasonable cost from any shop selling aftermarket parts for American V8’s. Standard size for the exhaust, and 1 ¾ inch for the inlet, ⅛ inch bigger than standard.

These valves come in the right size of stem for the existing guides. Collets and lash caps should be purchased with the valves (you may have to buy a set of eight, lifetime supply!) and installed: the tappets will then have enough adjustment to close the gap to the slightly shorter stems on the Chev valves. The standard 16H springs seem fine, but use of NOS items is advisable.

Close-up of area around the 1-¾ inch inlet valve.
Any bigger in valve size and the shrouding would be difficult 
to deal with, without unduly compromising the compression ratio.


The larger inlet valve facilitates a good three-angle re-cut of the valve seat, and allows the bowl and tract to be cleaned up - just grind off the obvious flaws, lumps etc - do not try too hard in this area. The exhaust is already too big so don’t bother, except to recut the seat. When re-cutting the inlet seat, recess it a little and relieve the area around it next to the cylinder head. This lets it match up better with the inlet relief in the cylinder deck. The valve is recessed so the top is level with the deck: no special science, just unwillingness to go too far. Hopefully this can be seen in the photos and the drawing.

Another shot of inlet valve and deck relief treatment, 
with hopefully more perspective.


The standard cams seem OK, for this extent of modification. No doubt more could be done with modified cams, but this would be serious development, moving away from the keep it simple, low cost philosophy.


Remove about 2mm or so off the head - on the head in the photos, the head is taken back to the level of the underside of the fin. Ensure the mating faces are flat, and use copper coat aerosol gasket for assembly rather than a gasket to increase compression. A substantial gain in compression ratio is needed, as the next modifications to improve breathing sacrifice some of this.

Check that the valves have clearance to the head at full lift: about 1mm is fine. Grind out the head just over the valves if the clearance is not enough. Grind the head so the combustion chamber is fair and smooth – take out the bare minimum of metal to do this - seek only to remove undue roughness in the casting.

Make sure the combustion chamber does not impinge on the piston at TDC - grind some clearance if so.

Relieve the cylinder head behind the valves – “Tuning for Speed” has a good drawing of this (above). There is a lot of variation between 16H cylinder heads: no two seem alike, so judgement must be used in these modifications.

Now, grind a pathway for the inlet gasses from the inlet valve seat to the cylinder bore. This was 5/64 inch deep at its midpoint on my bike. This modification is hard to explain in words: hopefully the photos are clear enough. Don’t make these so deep that you grind through the casting: however there is a fair bit of meat to work with. The exhaust was given no relief, as it was thought not to offer much advantage.

Round off the top edge of the cylinder wall facing the valves – not so much that you expose the top ring unduly.

With these modifications, some of the gain in compression ratio will be lost. In sidevalve tuning, it is a matter of striking the right balance between compression ratio and breathing, with the object being to get the highest compression pressure when running. The shape of the combustion chamber between the valves and the cylinder has a significant effect on breathing, being in effect a restrictive part of the inlet and exhaust tract. This balance is the reason the famous Harley sidevalve racers of the past ran CR’s well below 7:1. Striking this balance is a matter of trial and error, and doubtless results will vary depending on the artist’s interpretation.


The standard 16H exhaust is too big. Replacement means fabricating a new pipe, and this does move a little away from the standard appearance. The exhaust on my 16H works well, the pipe size is 1 ½ inch OD. The length is 1500mm from the port to exit of the muffler. The muffler is a straight through item, rather like a Burgess, which can be found in the carpark at any Vincent Owners Club meeting. Failing this, you can buy one cheaply from the aftermarket shop along with the valves.

My exhaust was arrived at by happy accident many years ago. The bike’s exhaust had passed its use-by date, and a friend made me a new one, a quick job to get back on the road. 1500mm is about as long as you can fit on the bike. With no other modifications at this stage, performance improved noticeably.


The WD 16H will benefit from a lot more ignition advance than book standard. However, the final figure will vary from machine to machine, depending on how the combustion chamber turned out. The best way of establishing this is to set a lot more advance than one would expect – well over 50 degrees. Then use the advance/retard lever on the road to find out how much advance your particular bike can comfortably use, and set it at that.

Within limits, the bike is not unduly sensitive to ignition timing in terms of performance. There is quite a range over which the engine seems to run well. There might be a temptation to use the minimum of advance that gives good running. However I have found that the maximum advance that gives good running gives a much cooler engine, important in a sidevalve. This only becomes obvious on longer runs. You then have to use the retard if you wish to lug up hills in top, providing more entertainment of course.

The standard jet, 160, albeit in the bigger carb, seems right for New Zealand 95 octane unleaded fuel. Fuel economy is a bit over 50mpg in oldspeak - OK for a sidevalve. Normal tuning procedures for establishing main jet size apply.


Installing a Model 18 engine sprocket - 18 teeth from the standard 16, is a must. The bike will pull this gearing with authority, and will be much smoother to ride. Even with the modifications the bike seems to be almost governed to 80mph, at which point it is well under 5000 rpm so safe for the cast iron flywheels.


My 16H, with the modifications as suggested, undertook a 2000 mile round trip from Auckland through the South Island of NZ and back. A footrest came slightly loose, and at one point I had to drain some garbage from the carburetor bowl. That was it for faults, and the longest day’s ride was over 400 miles. The route was largely over hilly and winding roads. The bike was a pleasure to ride due to its agility and torque.


Compression: Having milled the cylinder head down to the fin, there is still quite a bit of room between the piston and head – approx. 0.180 inch on my bike. This could be reduced to about 40 thou or so over the half of the piston away from the valves by bronze welding and machining. Raising the compression ratio in this fashion would provide a degree of squish to the benefit of combustion. It would also allow some sacrifice of ratio to further relieve the restrictive area between the valves and the cylinder.

Spark Plug Location: The original location appears to have intended to be kind to the sparkplugs of the day. The plug could be moved to approximately the centre of a triangle made by the valves and bore, for improved combustion with reduced advance. Either a new rebate in the tank or a 10mm plug would be needed. This also allows a longer reach plug as the electrodes will not be smacked by the inlet valve. The final position of the plug would have to take into account any revised combustion chamber shape.

Cams: This is an obvious one, but starts to get into expense and some design effort. The limitations on pre-war cam design seem to have been governed by the durability of the coil valve springs of the day. Valve springs have moved on, and if anyone is inclined to use one of the cam design applications, an improvement without loss of desirable low-end torque or reliability should be possible.

Carburettor: You could go bigger than the 1 1/16th inch carb recommended. I mentioned that the modified 16H seems governed to 80mph, the same speed as the Model 18. It is speculated that the governing effect is due to the carb size. Of course, cams and carbs raise the possibility of increased revs, so the cast iron flywheels, happy at under 5000 rpm, are potentially at risk. Steel flywheels would start to look attractive. I have a clip-fitting 1 3/8 TT carb I am tempted to try, restrained from this only by the laughter of friends. One advantage of a bigger carb would be the potential to improve the inlet tract; straight-sided with the 1 1/16th inch carb.

Combustion chamber shape: There is an on-line illustration somewhere of a sidevalve cylinder head by Prof Gordon Blair - this requires a flat top piston and probably a revised head casting - relatively simple in aluminium alloy. This seems to offer an improved combustion chamber shape. The Professor also shows a three-valve version. It is not my business to repeat any of this here, except to recommend a look.

Updraft Carburettor: As used by the famous Norton sprint 16H, in the article on this site. This has been used on an Australian BSA M20, made by cutting and welding, and has obvious gas flow advantages. This moves the appearance so far from standard as to be eccentric, of course.

Longer Inlet Tract: along the same lines as the updraft, but less radical in appearance. If the inlet port could be altered so the carb missed the oil tank, or indeed if the oil tank was modified, a good long inlet tract, like a vintage sidevalve TT Sunbeam, could be tried. A suitable length to match the exhaust, any modified cam, and carb size would have to be established. There is plenty of theory on this for a starting point.

Should anyone try any of the extra modifications, or other ideas, I would be most interested to hear of the results.

Sunday, 5 June 2016

1927 TT Start and Len Stewart

-SG- 'The Classic Motorcycle' magazine recently published a poster of the start of the 1927 Senior TT.  The photograph concerned has appeared before in this magazine in '84 with an accompanying article by then editor Bob Currie. It is worth drawing attention to the chap who started as number 2 on the grid - see scan. This was Len Stewart, an Australian and leading rider on the grass/dirt in his homeland at the time. He is mounted on a works Norton and how he came to be given a works ride is lost in time but, knowing the rivalry which existed then and now between Australia and New Zealand, it would not surprise me if the fact that New Zealander H H Moller was given a works ride the previous year did not have something to do with it! Be that as it may, Len Stewart's only foray into the TT ended abruptly when he fell off on, I think, the first lap. And if it's any consolation to our Aussie friends, Moller was just as unsuccessful!

However, the question still comes up from time to time: was Len the first person to ride in the TT on an OHC Norton? The TT start photo only shows the drive side of his bike of course - which tells us nothing - but there are those in Australia who think he deserves this minor claim to fame. However, the only photograph of him that I have located - attached, with practise numbers - shows him in the paddock mounted on an OHV cradle framed machine - fore-runner of the ES2 and incidentally without enclosed push-rod return springs. I have checked all the post-race reports I can find and none mentions - hardly surprising - which actual model he was riding, other than that it was a Norton.  So if anyone can shed further light on this conundrum, let's be hearing from you!

George Cohen

-SG- Sorry to learn that Dr J C Cohen ('George' to his many friends in the motorcycling world) died at the end of May after a long battle with cancer.  'George' was a flamboyant and in some ways, larger than life character and his well-known interest in single cylinder Nortons goes back a very long way.  He joined the VMCC in 1980 and bought his first flat-tanker in 1986. He became the Club's Norton marque specialist some ten years back, when Wally Flew gave up the post. He also did a short stint as editor of the NOC magazine 'Roadholder' and his major written work was probably 'Flat Tank Norton' which came out in 2006.

His comprehensive rebuild of the so-called 'Fowler 1907 TT machine', for the National Motorcycle Museum, was a major challenge. All credit to him for completing it/getting it up and running - and for personal reasons which do not need discussing here - declining to get involved in discussions as to its originality or other-wise!

I understand that his funeral is scheduled for 12 0'clock on 10th June, at the church next to his home in Chillington, Somerset.

Friday, 27 May 2016

Camshaft fixed

-JdK- Richard informed us a few weeks ago that his Model 18 camshaft had snapped in two; now he informs us the problem has been solved.

Richard: "I’ve made a fix for the existing camshaft as follows:

  • Bore the centre of the existing cam to get rid of the remaining intact portion of the shaft and to provide a centering/locating hole for a new shaft.
  • Make a new shaft (I used EN24T) with a central section that is 0.1”  thickness and is a press fit into the ID of the cam. 
  • Set up the new shaft in the bored camshaft VERY CAREFULLY to ensure the shaft and gear are concentric and then have the shaft and cam laser-welded around the circumference with a fine internal filet weld. I can’t do this myself but have found a local engineering shop that makes an incredibly neat job and will do this quickly and at a fair price.
  • Machine the phosphor-bronze bush in the outer case to get the correct end-float.

I have run a few miles since reassembly and all is OK so far. I’m entered in Banbury and if I make it to the end then I would say this has been successful."