Early OHV heads

A discussion spurred by pictures of a Model 18 Ron is selling; it's a 1928 model but clearly has an earlier cylinder head. The fins 'on top' are higher near the exhaust. The fins on later heads are all the same hight. Also check this entry.

Simon:"The good thing about this particular 1923 head (above; not a very good picture!) is that it still appears to have its original valves and springs - see the drawing (below).  Note that the valve sizes agree with recorded history that the early OHV engines had a larger exhaust than inlet valve.  I guess it's a bit 'anorak' to record this sort of stuff but it's not written down anywhere else as far as I know"

"Regarding valve springs.......I don't propose to go into detail about the various valve spring retainers as there are bound to be chaps who pop up and say theirs are different in some way or another! However it seems to me that MOST of the '26 to '28 OHV engines were fitted with retainers which take the following springs:

Outer - length 2.125 outer dia. 1.490 inner dia. 1.170 wire dia. 0.160 number of coils 7

Inner - length 1.845 outer dia. 0.950 inner dia. 0.740 wire dia. 0.105 number of coils 7

Peter Roydhouse made the comment to me a while back that Norton springs were unduly strong and he suggested using springs from post war 350 engines BUT the diameter of these may be too great for use on the open pushrod engines and one would have to change the valve spring retainers. Might be better to get the spring maker to use a slightly lighter gauge wire to reduce poundage although he would need to stick to the internal diameters given."

1923 Model 16H Norton

Sent by David in the UK

David: "I have recently unearthed this Norton 16H. It has been in a shed for the last 30 years and I think it is quite interesting as it has a separate oil tank and a mousetrap carburettor. I have been told it was raced by a Mr Jack Underwood. The bike will be kept in this condition and not restored."

Simon: "The numbers (frame number 65XX and engine number 42XX) match up - albeit the frame number is shown in the Works records as 65XXs. However the info in the records is disappointingly sparse. The model is shown as 16H and the magneto number as 122914, with Brown and Barlow carburetter and 26 x 2 1/2 tyres.  No gearbox number given. On the despatch details page, all that is entered is the 'card number' (I guess this is the works job card or build card for the bike) 3743. At this stage, this situation seems to have been commonplace - on this particular page (the first that exists incidentally) of 19 entries only 10 show the dealers to whom the bikes were sent and no end user details are shown atall. Despatch dates shown for the ten are all in the range November '22 to January '23. All were 16Hs. 


Regarding the 16H, it does look 'later'. I guess yes a 1923 model originally. I think the separate oil tank was fitted to the '23 works bikes and doubtless could be ordered if wanted but perhaps was a later fitment. The tank looks wide for this date. Also note the forks are the posh variety of Druids with the dampers - not fitted as standard. Fitting a mousetrap Binks was the twenties equivalent of the 'go faster' stick-on stripes for cars in the fifties/sixties. But bear in mind that the early twenties 16H could be made to go. Driscoll reckoned his ex works 16H was better by far than the first OHV bike he got! The oil pump is a later fitment too - furthermore it is a Pilgrim and not a Best and Lloyd. 


I don't know of any Jack Underwood though there are a couple of J. Underwoods who were VMCC members in the 1988 VMCC members list - one living in Blandford and the other in Crawley. One of them (the Blandford one) was a member in 1973 but neither in 1960....Judging by the Blandford Underwood's membership number he must have joined the club in the late sixties.  None of this is really much help!"


Martin:"The registration is a Gloucester County Council one issued in 1929, so whatever it did between 1923 and 1929, it did so with another identity.  By 1929, a 16H would have been passe, but as I know from running a 1920 16H, they have a lot more spirit than many early OHVs, and it would still have been a capable performer in 1929."

Grandfather's c1923 Model 18 Norton

Sent by Al in the UK.

"This shot is of my grandfather (who was a great Norton fan who used to visit Brookland regularly pre war) and my grandmother on his Model 18 at Hayling Island, Hampshire sometime in the late 1920's. I wonder if PC 3978 is still around. (JdK: PC 3978 was issued from July 1921 to July 1923 by Surrey C.C. (currently Guildford). It probably is a 1923 model then. Quite sporty, note the narrow mudguards, open primary chaincase and open exhaust). I've been trying to get hold of a flat tank Model 18 for ages similar to his! I'm looking for a flat tank Model 18 - project / box of bits, or what have you ? I have a 1923 Sunbeam 500 sv Sports TT short stroke flat tanker, 100% original for possible exchange; the bike is MOT's and taxed with a rebuilt engine. (below)"

Anyone interested in a swap can contact John

1923 Model 18 cylinder head - For sale

Chance to buy a rare very early OHV Norton cylinder head dating from October 1923 (stamped 23/10).  This head has had valve seat inserts fitted at some stage in its long life, and has regrettably sufferd a fair amount of fin damage which will need to be repaired, but the head (including the threads on both inlet and exhaust ports) is basically in sound condition. On Ebay motors, item 260773524448. See this blog entry for the difference between early- and later M18 heads.

Mark's 1923 Model 16H Norton

An email from Mark

I am in  Cape Town South Africa and have a 1923 16H (above) and I am in need of a piston and if possible a barrel as well. Mine came with a bad score inside from the gudgeon pin and has an incorrect piston that somebody has machined the shoulder almost completely off; it does not appear to ever have run with this piston. Who has a spare barrel and piston available? The gudgeon pin is ¾” ( 18.87mm).

Simon: "My piston data shows that the gudgeon pin was 5/8" not 3/4" and the piston was cast iron, as one would expect. The Hepolite number for it is shown as 269 or, in aluminium (slightly later but still 5/8" pin) number 1509".

Barbara and Laurie's 1923 Model 16H Norton

These magnificent photographs were sent to me by Judith Taylor and they depict her parents on their 1923 16H Norton. Judith: "Regarding the motorcycles, I don't think that there is much of a story really. My parents (Barbara and Laurie) would have been engaged at the time. My father was always a keen enthusiast for 'wheels', but probably could not afford a car just then. My mother always said that she did much of her courting on a motorbike"

Registration OK9675 was issued in Birmingham between January 1922 and July 1923 which confirms my guess that the Norton is a 1923 model. The 16H looks quite new in the picture below. The thing protruding from the top of the handlebars is almost certainly a personal mascot; a doll, gnome, pixie or even a policeman as it seems to be wearing some sort of helmet!

Reece's c1923 Big Four Norton

Work in progress! This is Reece's 1923-1924 Big Four Norton.

1923 Model Big Four Norton

An email from the USA:

"Hello, I'm hoping that one of your Norton aficionados might be able to help me with the attached photos. The gent driving the outfit is my great grandfather William Gegg, and I do know that the picture was taken in 1923 or earlier. I think it may be a Norton, but I would love to be able to confirm this, as the photo is posted on my family's Ancestry.com page and we're trying to identify all of the machinery. If it's any help, the photo was taken in North Yorkshire, near Scarborough.

Thanks in advance for any help!
Gordon
Wisconsin, USA"

The picture above was copied from a brochure front cover for 1923 and it looks very similar to me; the shape of the tank at front identifies the machine as a Big Four. Noteworthy accessories are the electric lights and does the bike have a front drum brake? The photo below may be from the same 1923 brochure.

...and Gordon's reply:

"The younger lady in the photographs was my grandmother, who passed away in 1923 after giving birth to my father; we now know that these may be the last photographs taken of her and that she could have been pregnant with my father at the time. The gentleman, William Gegg owned a popular confectionary and restaurant in Scarborough, the older passenger is his wife Margo, and the younger is my grandmother, named Eveline."


...and from Roger:

The pictures of the Big 4 are intriguing. Although they may have been taken in 1923 I am not so sure that the machine was new at that time. The North Yorkshire registration is a lot earlier that 1923 as by the middle of the year then next letters were being used. As the series started in 1904 and went up to 9999 the registration date is likely to be around 1920; this could date the outfit to around 1920 which may be right for the motorcycle and sidecar. The electric lighting set would have been available by that date but we need to check whether Norton made it an option as this may be the best dating evidence available. The outfit looks well used so this would support the date.


I think that I can see the rod for the rim brakes in the side on picture. In addition the tax disc for 1923 should show a vertical green stripe. The disc is either not there or is of the 1921/2 type with no stripe.

Dan O'Donovan and Bert Denly

Dan and Bert in a sidecar racer;  it looks like a 588cc Model 19 and the lack of friction dampers on the Druids may date it as a 1923 machine. Note the skid under the sidecar body that was used at Brooklands to prevent a catastrophe if the sidecar wheel failed.

Martin's comments: "The front and rear wheel rims are Westwood section beaded edge rims while the sidecar wheel is a flat center beaded edge rim, all of which date from perhaps 1923-1924, but the MkII Druid forks may be 1925 or later (see below). They have also fitted a wire device taped across the front tyre called a "Carlton Tyre Saver" which skims the tread as you ride and knocks flints out before they cause a puncture. The sidecar body looks to be skinned in doped canvas and flimsy is too strong a word for it! Denly must have been a brave chap to ride in such a thing..."

Roger in his book also discussed this loop of wire fitted to the front forks with insulating tape. During one of his runs, Bert's back tyre picked up a coil spring from a roller blind which embedded itself in the tread and as the wheel went round the spring lashed Bert's backside. After that incident, these "nail catchers" were fitted to all of his Nortons. The characteristic Denly nail catcher can even be used to identify Bert's bikes, like this one.

...and more comments from Roger: "The sidecars' rims were of the flat beaded edge type right the way up to 1932. Bert used the Westwood section until he joined AJS in 1929 but Pat changed to well based rims in 1927 (see the pictures in Doctor Bayley's book "The Vintage Years at Brooklands"). The picture could have been taken before 1924 which is when silencers were made mandatory at the Brooklands track (the Norton is running the standard length open pipe) and Bert didn't join the team until 1923. I am not sure about the Druids but George Cohen states that the Mk II's were introduced in 1922. The sidecar in the picture may be constructed from strip of wood which can just be made out.  Bert would lay face down and feet forward in the chair for the duration of an outer circuit race.  

R.T. Grogan wins again.

In this picture R.T. Grogan has just won the 1000cc Three Laps Handicap Race at Brooklands on the 18th of August 1923.

The bike is a 490cc Model 18 and appears to be the same motorcycle as he used to win the 200 miles solo race in 1924; he did fit other handlebars though.