Girder fork design changes

And some were Webb and some were Norton IIRC ?

Hi David,

   I guess your query follows on from your Inter post, but it is a War & Peace size subject ! The Norton production year ran from October to September, which is a bit confusing when trying to reference parts to a particular year, so I tend to refer to a season rather than a definite year.

   The International specification split into 2 specifications from around mid 1933, standard road spec. and to racing spec., so I will start with the standard type first.

   The Inter was announced in October 1931 and the forks were the first of Norton's own design using the splayed type blades with the detachable left side brake drum in common with the rest of the range. These had the Andre steering damper and side friction dampers, but no check springs, which were not fitted as standard until the following year. For the 1934 season the blades were made parallel and copied what was being used  by the works racers and these used the one-piece right hand side hub. Over this 3 year period the handlebars were clamped to the top yoke by a single 4 bolt integral clamp. For the 1935 season this clamp was replaced by the rubber mounted version with the handlebar clip bolted to the top yoke. The following year saw more mods with the brake anchor made bigger and the cable stop moved higher up the fork leg. The forks remained unchanged until WW2 stopped Inter production, and during this time the check springs stayed the same tapered profile.

   As Richard T. says the works racers used the Webb type forks at the beginning of this period, but for 1932 Norton made it's own version with parallel blades, no side dampers, but check springs which were parallel in shape, but small in diameter compared to the later ones.The 2 handlebar clamps on these had 4 bolts each and were the same as used in the 1940s. By the end of 1933, these forks were available to private racers as part of the racing specification. These racing forks were changed at the same time as the standard type with rubber mounting handlebars and brake cable stop bracket. The only other change was the larger parallel check springs first used on the works in 1936 and private racers in 1937.

   This is not a definitive account but if you can get some close-up photos I can identify what you have, or have a look at    www.vintagenorton.com    but only trust period photos.

Hi again David,

   I had a feeling George C. had been involved, he seemed to replace original petrol tanks on most of his rebuilds and I don't know if he was aware when the gearbox indicator was changed. I guess these up-dates are beneficial, it just depends what you want. I shouldn't dictate as my Inter is much the same as this one.

   The forks on your(?) bike are from 1936-9, but it has the non-rubber handlebar type top yoke perhaps from a WD or 1946 machine, which may have been George's idea to make them seem older. The parallel racing check springs look like replicas made in the 1980s/90s. In answer to your question about the brake cable lug, yes it was supposed to allow you to adjust it while riding, but in reality it would need to be spring loaded to work quickly.

   The bike looks like it has some good bits on it, Manx cambox, rev. counter etc. so will make a good machine.

There most certainly were gearboxes for the right hand fitment, not just for Inters and bikes with the £5 extra 'Trials' option, but also 1939 and 1946...The hub gear has a left hand thread too. Much harder to find than the common or garden WD type which still turn up NOS. It is possible to convert a chronometric to deal with the alternative cable direction - Royal Enfield used them for a few years for some reason.

Did the Inters change to the smooth mag chain cover for 1938 as well ?