EXPERT ADVICE & HINTS and TIPS

THIS PAGE CONTAINS INFORMATION ABOUT REBUILDING YOUR NORTON,

 and other interesting material. SCROLL DOWN THE PAGE…………………..

The hints and tips have come from my own experiences, which have often been learnt the hard way! If you have any good ideas then please do not hesitate to send them to me and I will include them on the page .......we have the responsibility to keep these fine machines in good working order.

"It is true, that we cannot tell at once whether we have really gained any new knowledge by this or have only enriched our store of formulas................."

Sigmund Freud, 1923. The Ego and the Id. S.E. vol XIX p.152.

The most wonderful point about the norton machine is its graceful, and almost fragile, appearance; it looks the beau ideal of elegance, in fact it suggests effeminacy; you find yourself wondering where its marvellous strength, and power comes from. it is so scientifically designed, that the art of its construction conceals its herculean capabilities, it must have taken years of study to perfect such a "multum in parvo" of power. it may be driven at a walking pace or at 50 miles per hour, or if a greater speed is desired an 8hp machine will carry you along at 80 miles per hour with perfect comfort if your respiratory organs will stand it.

From the Gentleman's journal, 11.2.1911

 

CLICK ON BLURRED PICTURE FOR A CLEAR ONE!

This is my five year old daughter on the  1926 Model 44 racing outfit!(summer 2000)

Click on image for a larger picture

PLEASE BE SPECIFIC ABOUT YOUR ENQUIRIES

 

This is a picture of my 1926 TT Norton; click on thumbnail for a bigger picture

Similar to a standard road going machine (the famous Model 18) it features many ‘go-faster goodies’ inside the engine.

 Also has eight inch brakes front and rear, TT Amac carb, Lucas TT magneto, straight pull twist grip, TT gearbox……

 

1001 "Guinea tips" from the "Doctor of Reason, Soldier of Fortune"

1. NEVER blast clean an oil tank. And if possible do not blast clean anything. One stray bit of grit, stuck in a crevice with burnt old oil and shit for fifty years can at a later date cause havoc! Elbow grease works best!

2. If you blast clean crank cases, the ONLY way to make sure that all of the crap is clear of the internal oil ways is to use: extra long twist drill bits ( 3/16th & 7/32nd inch ) and to turn them by hand through the oil ways. High pressure air and cleaning fluid may not clear a partly occluded oil way; I learnt this the hard way!

3. Piston clearances: bottom skirt clearance 0.005 inch and up to 0.010 for racing machines

4. Oil leaks from SOHC engines. Make sure that the cam shaft tunnel is not broken, due to worn rocked pads allowing the bottom side of the rocker arm to hit the tunnel. I can repair this defect. See tip 21, below.

5. Avoid drinking too many beers before riding your machine. The well known "sloshing effect" of a large quantity of fluid in the stomach can induce tank slappers. My friend, Roger, is currently experimenting by eating a meat pie with every pint of beer he drinks, prior to climbing onto the machine, to reduce the effects of sloshing. We are currently analysing lap times and further information on this topic will follow………..!

6. Gearbox tip. On upright/ "dolls-head" gearboxes; the upper mounting "ears" have a tendency to break. This is usually due to the lower mounting hole in the case becoming elongated ( rugby ball shape ) which allows the gearbox to twist as the engine wants to pull it forward and the rear wheel wants to pull it back! The solution is machine and fit bushes which are precisely 1/2inch I.D. and line ream them together. The idea is eliminate any slack from the lower fitting. (see below).

 

click thumbnail for larger image

7. OHV VALVES AND GUIDES

500 cc OHV NORTONS FROM ABOUT 1934 TO 1962 use roughly the same guides and valves. Depending on the source of information, Tranco or James catalogues, the dimensions are as follows:

 Guides : total length 2 5/32 inches    length to flange: 1 5/8 inches  bore 3/8 inches O.D. 5/8 inches

 Valves: head diameter 1 3/4 inches Stem diam 3/8 inches  Stem length from 4 5/32 to 4 5/16 inches

Head style semi-tulip Stem head taper groove

 Guides are cast iron. Remember to check the I.D. of the apperture in the head………you made need an over-size guide

  •  Also remember to use a good quality metal for the exhaust………they run red-hot and unless you use a good un' it will burn out. Use austenitic steel such as KE965 or Jessops G2 or an EN 54 which is a high nickel-chrome- tungsten. These steels are non-magnetic, but require valve caps to prevent rocker-clout wear.

1935 ES2 cylinder head with re-cut valve seats. Thin blue line depicts narrow seat on inlet: to allow maximum gas flow on immediate opening and perfect tick over. Thicker exhaust valve seat helps with dispersal of heat from ‘red hot’ valve. Easy job by using ‘Neway’ triple valve seat cutters. First cut is at 60 degrees, second at 31 and final cut (for seat) is at 46. Picture and diagrams demonstrate, click on thumb nails.

                

 

8.  GEAR-BOX TIP replace drive side lay-shaft bearing (40mm O.D.x 17mm x12mm) a no. 6203...........by..........a NJ203 roller

9. PETROL TANK PAINTING

In response, to numerous enquiries regarding petrol tank painting; and to save me time on e-mail replies...................here are my ideas. beware of the idea of "original". painting of tanks in the pre- and post war period was done by hand and on some days of the week, the hand reponded to its brain in slightly different ways. ( i once met an old chap at the isle of man, who actually was a painter at bracebridge street and he told me this! ) sales litertaure does not always follow the style that left the factory. some tanks were chrome plated, some were in dull nickel, some were never plated. panels were in silver with black and red lines. in the majority of tanks the red line was inside the black, but occasionally this was reversed!! i would never recommend re-chroming a petrol tank. the amount of pre-plate polishing required to provide a suitable service for chroming, leaves the metal dangerously thin in places and with disasterous consequences!!!!!!

I like the following, which although not original, looks better than the pictures depict! where the chrome should be is silver and where the silver is, is polychromatic grey !!!!!!!!!!!! ( both norton colours ) click on thumbnails to see what i mean.....

INCIDENTALLY, THIS MACHINE IS NOT ORIGINAL EITHER.

 IT IS A SHORT STROKE ES2 MOTOR (NOW 84mm bore and 79mm stroke ), downdraught inlet track, two spark plugs, and a lot of special bits inside! Incidentally, the paint was applied by JBS MOTORCYCLE PAINTING ( check them out on my links page )

10. Norton silver can be replicated by using:

1974 VW Beetle silver, or

Vauxhall star silver mist, or

Vauxhall silver starfire metallic,or

for a "greeny" patina, then use Vauxhall Platinum starfire metallic

Rover siver leaf, MME421 is also a good match.

POLYCHROMATIC GREY: Fiat dark grey metallic; Ford Granada pearl grey mettalic

or VW Audi platinum ( ICI: L98G 9305B )

11.

CLICK ON THUMBNAIL TO SEE HOW SEVEN PRE-WAR INTER' TANKS ARE ALL DIFFERENT!!!! THE ONE AT THE END IS A NEW REPRODUCTION IN ALUMINIUM.

12. The 40mm X 17mm X 12mm bearing for the lay shaft is identical to all pre-war single sided brake-drum hub bearings, on the "spoke" side. on the "drum" side they were same OD and ID but wider at 16mm because it was a double row ball.

13.      QUITE SIMPLY THE BEST INFORMATION ON PREPARING OLD MOTORCYCLES IS TO BE FOUND IN PHIL IRVING'S TUNING FOR SPEED, WHICH WAS TAKEN FROM HIS SLIDE RULE ARTICLES.

 

14. CLUTCH INFORMATION

The AMC clutch was a re-design of the old Norton clutch. Dimensionally, it is the direct replacement and the two are interchangeable. But the internals are quite different. Whereas, the Norton has inserts in the chain-wheel and externally driven friction plates, the AMC is exactly opposite. The chain-wheel is solid and the friction plates driven internally. This was an improvement over its predecessor, especially in racing, where the old Norton clutch had some shortcomings. So although the two clutches are identical externally, and completely interchangeable, the components are not, with the exception of the pressure plate, which is pressed steel on the Norton, and alloy on the AMC. You can use the AMC pressure plate on a Norton clutch, the only advantage is that it won't rust when you run with open primary drive. The AMC was fitted to all the big AJS, Matchless and Nortons which used the AMC box from 1957 right up to the Commando. Either clutch will fit any Norton or AMC box from 1934 to 1978 including Commandos.

When setting up the clutch, it is extremely important to make sure all the plates are flat, any bent ones should go in the bin! Make sure the securing nut is tight; use a clutch holding tool. Make sure that all three springs are the same length and strength. When fully assembled, with primary chain on, and machine on stand ( ie rear wheel in the air ); put into first gear. Pull in clutch lever, and spin rear wheel. Note if the pressure plate is lifting evenl…..if not adjust the appropriate spring. Always allow free play on cable ( to avoid drag ), especially with races which have clutch starts. Good luck.

15. NEVER run your primary chain too tight; 1 to 1 1/2 inches up and down movement.

16. As a consequence of the effects of gravity, the contents of the oil tank finds its way past the gears of the oil pump to languish in the bottom of the crankcases. This phenomena is known as "wet-sumping". The time it takes to significantly wet-sump varies: a machine left for a few weeks may accumulate enough oil ( a pint or more ) to hinder the movement of the fly-wheels and therefore starting……

……. THE REMEDY: FIT AN OIL TAP AND REMEMBER TO TURN IT ON!!!

A ONE WAY VALVE IS A POOR OPTION BECAUSE YOU CAN NEVER BE CERTAIN THAT IT HAS NOT GOT STUCK CLOSED.

IF YOU SUFFER WITH A POOR MEMORY, LACK OF CONCENTRATION OR ARE JUST PLAIN STUPID; THEN WRITE IN LARGE LETTERS ON TOP OF THE TANK THE WORDS "OIL TAP". OR YOU CAN FIT A MAGNETO CUT OUT ON THE OIL TAP.

 

17. Dolls head and up-right gear boxes are liable to break the top mounting "ears". This is usually due to a fault at the lower mounting. The lower mounting hole tends to "elongate" in a fore and aft directing as a consequence of the engine trying to pull it forward and the rear wheel attempting to pull it backwards. The bolt also wears.When this happens to a severe degree then the top mounts are put under strain and eventually break. The remedy is ensure a perfect fit of the lower mount. I bore out the "oval" holes and fit bushes which are lined reamed together so that there is a exact 1/2 inch hole ( and perpendicular to the frame ). Sometimes "top hat" bushes are required to take up any slack in the transverse dimension. Make a new bottom bolt. The aim is to establish a snug fit of the lower mount

18.   Gearbox data   click for information about gear boxes, courtesy NOC. 

19. All aluminium cylinder heads exhaust ports with internal threads, where the exhaust ‘Nut’ or ‘Ring’ screws in are liable to damage. Over the years, the combination of vibration, lack of maintenance and ‘wear and tear’ means that one day the set up gives up! Here are a few tips. It is best to undo the ‘Exhaust Ring Nut’ (ERN) when the cylinder head is hot or at least warm, so that the relative expansion of the alloy cylinder head allows some loosening. If you have a cold engine and the ERN appears tight then use a Hot Air Gun (a very useful tool to have in the workshop) to heat the adjacent area. If you are working on an engine which has stood for many years, the inevitable carbon deposits in the exhaust port will have found there way onto the threads of both male and female components. In combination with other dirt and muck, this acts as a ‘grinding paste’ and undoing a tight ERN under these conditions can cause a lot of damage.

            If on inspection the internal thread is damaged and/or worn and consequently the ERN is either a sloppy or poor fit, then a repair is required.

            I mount the head on an angle plate on the Mill and bore out all the old and damaged threads. I then measure the ID of the smooth bore left; add two thousands of an inch to this dimension. Now make up a sleeve which has its OD to the same numerical value; in other words it will be 0.002 inch larger than the hole! Internally screw cut a new thread which compliments your ERN, which will be in perfect condition; if not you must make or buy a new one. The length of the sleeve should be about 1/8 th of an inch longer than the depth of your hole. When your new sleeve is finished, shove the cylinder head in the oven for ten minutes and then drop the sleeve in and finish off with three (120 degrees spacing) small welds to ‘belt and brace’ the job. The reason for making the sleeve 1/8 th inch too long will become apparent when you do the welding!

            Your ERN should be a perfect fit. When tightened up, finish the job with lock wire or other locking device and your pipes will never dangle!

 CLICK ON THUMBNAIL

20. “FREDS”

 

DIAM.

UNF

BSF

BSW

UNC

CYCLE

 

3/16

32

32

24

24

32

1/4

28

26

20

20

26

5/16

24

22

18

18

26

3/8

24

20

16

16

26

7/16

20

18

14

14

20/26

1/2

20

16

12

13

20/26

9/16

18

16

12

12

20/26

5/8

18

14

11

11

20/26

 

3/16 UNF  ~  2BA (31.4 TPI)               BA = 1/8,  (38.5 TPI)

 

21.Inter’ Cam Box Repairs

          The single knocker cam box, as used on all the ‘cammy’ models from 1931 to 1958, is a poor design, is prone to break, is difficult to work on and it leaks oil like a primary chain case! Why Norton persisted with it for over 25 years is anybody’s guess? Most of the research and development was done on the double knockers, although in 1935 the works machines sported an enclosed cam box.

            The most common fault with the cam box shell, is a broken tunnel. This is usually due to excessive wear at the rocker pad ends, which in turn means that the underside of the rocker hits the tunnel, causing the latter to break up (marked with a red line in the photograph).The purpose of the tunnel is to keep as much oil at the cam to rocker pad interface as possible and when it is broken, the oil loss from the cam box becomes so bad that most of the riders bottom half and the machines rear end are drenched in the stuff! The tunnel can also be damaged by inexperienced mechanics (bl..dy idiots) who do not know how to remove cams and replace pads.

            The next most common fault with the shell is a broken ‘leg’ due to someone failing to check that all four mounting points for the cam box are perfectly horizontal and square (extended head bolts on the Models 30 and 40, individual spacers on CS1 and CJ).

            As in all alloy (or magnesium) castings, threads are often damaged and mating surfaces scored by careless use of the wrong tool!

            To repair the tunnel, I machine away the broken item so that I am left with a cam box minus its tunnel. I then make a new tunnel from a piece of alloy tube (2.125 inch o.d.) and use Araldite and a 2BA countersunk screw to fix it in place (see pictures). There is more than one way to machine the cambox; spin it and hold the tool or viscera-versa!

          When working on the cambox, I use a variety of special tools and jigs. The simplest ‘holding jig’, taken from Garratt, can be easily made from a six inch length of hexagonal bar and two 3/8 inch studs. It makes life very much easier. Being hexagonal, the jig can be turned round to work on both sides of the cambox, tilted at a convenient 30 degrees.

            Once the cam box shell is perfect, then all the other components can be repaired and rebuilt. It can take a very long time to do all this work and it would take me even longer to write a manual on SOHC cam box re-building! My advice is to NOT do this work unless you have someone with previous experience to show you how. There are many potential traps!

 

      

Click on the thumbnails for pictures…

 

Inlet Valve Opens     57/58 BTDC

Inlet Valve Closes    60 ABDC

Exh Valve Opens     85 BBDC

Exh Valve Closes     42/43 ATDC

 

This is for Megga or open pipe. With silencer retard inlet by 10 degrees, ie 47/70

 

These timing figures can only be achieved when there is no wear to the cams, or rocker pads. For timing the cams from scratch the following procedure should be adopted:

  1. fit a degree disc to the engine mainshaft, locating ‘zero’ with the piston at TDC.
  2. set both valve clearances to 0.004 inch ( these are the setting clearances )
  3. with cam box assembled on top of the engine and the top bevel cover removed, unscrew the hexagonal nut ( right hand thread ), which locks the bevel onto the cam shaft. This will enable the peg which locates the bevel to the cam shaft to be removed.
  4. revolve the engine forward to the position where the exhaust valve should commence to open ( 85 BBDC ).
  5. Rotate the camshaft in an anti-clockwise direction until the exhaust cam contacts the exhaust rocker. As the locating shoulder on the camshaft has 11 holes and the bevel 12 holes, it will be found that the locating peg can be inserted through both components where the two holes coincide.
  6. Replace the nut locking the bevel and check the opening and closing points the exhaust cam, repeating the procedure as required to obtain the correct timing. This vernier adjustment gives a crankshaft movement of approx. 5 degrees, thus allowing a reasonable accuracy.
  7. The inlet cam is located to the exhaust by means of a small roller connecting the two cam faces. The eleven and twelve holes allow a similar vernier adjustment as before. By inserting the roller in the appropriate holes, the required setting for the inlet cam can be made. The usual combination of holes is :

 

Exh      No. 5   Inlet  No. 1

Exh      No. 6   Inlet  No. 2

Exh      No. 7   Inlet  No. 3

 

  1. Cam timing is made with a 0.004 inch clearance between rocker and valve.
  2. The above process may need to be repeated until the correct figures are obtained. Rotating the camshaft in a clock-wise direction, advances the exhaust cam. Moving clockwise round the inlet cam holes, advances the inlet.

10.Good luck!

 

         Norton International cams  

                                                             INLET           EXHAUST             MODEL      

                   

                        1932                               E41.33            E41.34                   40                     

                        1933                               52.40              52.39                      30                   

                        1937- 39                         63.92              63.93                      C.S.1.                

                        1937                               68.93              E63.87                    30                    

                        1939                               39.40              39.39                      40M                  

                        1948-52 & EARLIER?    62.12              62.13                      30                    

                        1946-49 & EARLIER?    115.87           115.88                     30M                    

                        1953-58                          64.66              63.89                      40M                   

                                                                                      77.63                      40                  

               1937 WORKS ENCLOSED C/BOX   4IN                  4E                          30M 

 

These numbers probably mean something, but I have yet to break the code!

You would have thought that they may correspond to the cam timing, but they do not!

Anybody know the answer?

 

22. RIGID AND PLUNGER (GARDEN GATE) FRAME BREAKAGES

 

Norton first introduced rear suspension in 1936 for the works entered TT race machines. With heavy castings and un-damped ‘suspension units’ attached to the rear of a rigid frame, a few of the bumps on Monas Isle failed to make their way to the backsides of messers Guthrie, Frith and White. With the extra weight and decreased rear end rigidity, the already brittle frame which was prone to fracture on the saddle down tube, just above the gear-box top mounting cast lug, was put under further strain.

          On both rigid and plunger frames I have frequently come across such breakages in both the workshop and on the road.

          I have recently bought a 1939 Model 30M, which was raced by Victor Gaunt in the ’46 and ’47 MGP races. He had bought the machine in early 1939 to race in that years MGP, but ‘The Hun’, put a stop to all that. On stripping the machine I found that the frame had cracked just above the gear-box top mounting casting, it had been repaired in the past, but had cracked again.

Click on thumbnail

 

Incidently, this frame with the rear suspension units and “suicide” rear stand weighs in at a wopping 21.5kg (47 lbs). A rigid frame weighs about 15kg (33lbs).

 

          It is important to carefully scrape away the paint from this area, even if a crack does not appear apparent. Beware of powder coated frames; I never use powder coating because its thickness masks the early signs of cracks.

          Having cleaned up the offending area, I then considered the best way to effect a repair…………. I sat down for a good pint of ale.

1.     A top hat washer at either end, with a sturdy rod threaded at each end. Two nuts and the fractured tube could be pulled together, firmly and the fracture line ‘welded’. (either gas weld, TIG weld , sif-bronze or silver solder)

2.     A rummage in my tubing stock revealed a length of seamless 16 SWG tube of 1 1/8th inch O.D. Perfect; light and strong. BUT would fit!  Like f..k it would. The I.D. of the saddle tube was 1 1/16th inch.

3.     A further rummaged found a heavy piece of cast seamed tube with a wall thickness of 0.135inch and an O.D. of 1.060inch………….this will be close. I cleaned up the inside of the saddle tube, both from the top and the bottom with a motely collection of scrapers and air-tools. I then bashed the new tube down the hole, breaking all the casting lug ‘nails’ which are used in the original frame building. A perfect fit. I then bashed in reverse, to remove the tube and put it on the scales………..2lb (almost 1kg)…. Ahhh!  I put the tube in the  lathe and skimmed down 35 thou, (reducing the wall thickness to 0.100 inch) Plenty strong enough! Where the tube is adjacent to a casting/tube joint, I left it full wall thickness; a nice snug fit in precisely the area you need the strength.

Click on thumbnail

 

I then had another bottle of fine ale and considered the final touch. Having got everything as clean as possible (removing 70 years of road shit and castor oil mixed as sticky paste from the bottom of the saddle tube), I thought about the fixing of the tube? Was there a need for a couple of strategically placed pins (1/8th inch diameter, on a 1 degree taper, and tapped through a 1/8th diameter hole tube in both the new and old tube AND then silver soldered? Should I TIG or silver solder the top and bottom of the new tube inside the old saddle tube? How about a good dollop of ‘J B WELD’ in the significant places?

I finally decided that because my fortuitously found piece of tube was new (and hence easy to get scupriously clean) and with some careful cleaning of the inside of the original saddle tube; I brazed the new tube at the top and bottom. No need for any other fixing and hopefully the new tube will hold it all together.

          All in place, drink lots more beer, assemble the machine back together and off for a good thrashing down the lanes!!

 

 

 

     23. to 1000………..still in my head!

1001.THE MOST COMMON enquiry that I receive is about whether or not a machine is in "original" condition or specification. The answer is: "NO and do not worry about it!!" Allow me to explain. In the days when you could order a NEW Norton from Bracebridge Street (and especially in the 20's and 30's period), a prospective purchaser could order "plate and polish" which was extra chrome et al, a sprint size petrol tank, or a large capacity IOM tank, different wheel sizes, in trials trim, with or without lights, folding kick-start, etc etc etc. Racing machines were frequently broken and re-built with the latest components (which probably were a year or two later than the original machine). Owners changed handlebars, paint schemes, and made sensible (and occaisionally ridiculous) modifications......So how do we know what is "original"??? My 1920 Brooklands Racer has a circa 1940 carburretor on it, which seems to offend some people. My reply is: "If you can tell me where I can get the "original" one from then I will put it on the machine, provided it performs as well as the NOS 1940 item! The important point is to assemble the pile of bits into a working machine and then worry about trying to trace the "right" style handlebar rubber at a later date!!!

MODIFICATIONS CAN BE MADE…………………….

 TO MAKE THESE MACHINES BETTER THAN WHEN THEY LEFT THE FACTORY …………………

 

 

CLICK ON THUMB NAIL TO SEE a special. I MODIFIED A 16H FRAME TO 500T SPECIFICATION, USED GENUINE 500T PETROL TANK, OIL TANK, FORKS, YOKES, FRONT WHEEL AND SQUEEZED IN A CIRCA 1938 CJ MOTOR………….MUCH MORE INTERESTING TO DO THIS THAN TRY TO RETURN TO ORIGINAL CONDITION….SO MANY OF YOU GUYS OUT THERE ARE HARBOURING POTENTIAL NERVOUS BREAKDOWNS IN YOU QUEST TO OBTAIN ALL THE ORIGINAL BITS; USE 'EM, BREAK 'EM, MEND THEM AND ABOVE ALL ENJOY .

 

This picture has a story. While attending the Vintage Sports Car Club meeting at Wiscombe Park, Devon a few summers ago I was approached to take this very dear lady for a ride. Her name is the Honarable Bardi Frankland and she is 91 (ninety one) years old. She chose my mount, in preference to the two Bugattis, the ERA and the Alfa Romeo for a spin up the hill-climb! You certainly meet the most remarkable people while riding pioneer machines.

 

ride back to the start!