Clubmans's Inter?

Dear Paul,

If you can get a copy of Roadholder 304 I wrote an article outlining the differences of a featherbed Clubman's Inter. I didn't know all of them and Ken Sprayson added further infrmation in Roadholder 306 again for featherbed framed versions. Some of the information may be relevant to your machie,

Regards,

Peter Bolton

Hi Paul,

When the International was re-launched in 1947 it was the basic specificationof the pre-war models, apart from having telescopic forks and rear suspension as standard, and with the lack of aluminium etc. there were no optional extras. With the introduction of the clubmans class in the TT, which was a production machine class, riders sort the pre-war machines with all alloy engines to give them an advantage over the cast iron versions. As supply conditions improved optional parts became more available and it was in Nortons interest to provide competitive machines. I don't think there was a definite divide between a standard Inter and a clubmans, it was just a case of how many extras you could get/afford. By the time Geoff Duke rode in the 1949 event his bike had an alloy engine with a Manx SOHC cambox and a bolt-through petrol tank. As the Manx went into the featherbed era, the Inter had more racing parts and in the final garden-gate year of 1952 the frame was virtually the same as a 1950 Manx. I think by then they all had alloy engines with Manx cam boxes and bolt through petrol and oil tanks, so all the cubmans parts as standard spec. Regards, Richard.

Hi again Paul,

The crankcases on your bike should be aluminium as the dull grey magnesium alloy ( known by it's commercial name Electron ) crankcases fitted to the Manx are significantly different to the Inter, although the barrel and head will still fit both. The ManxSOHC cambox on the other hand is a direct swap for the aluminium one and only needs the oil feed pipe tweaking. The bevel housings would have been aluminium originally as the magnesium ones were only fitted to the Manx and most likely have been fitted retrospectively to your engine and are also a straight swap. The head and barrel are correct for 1950, the full alloy heads came in for 1951. I am not sure when the bolt through oil tanks came in as they werelater than the petrol tanks so it could be original or may be another retro fitted item. The big advantage of magnesium alloy is that it weighs about 2 thirds of what the ordinary cast alloy does. Regards, Richard.

Previously paul_nicholls wrote:

Thanks for all the information.

I bought the bike recently from a friend in the USA. I believe it is as it left the factory except for a poor repaint along the way. My friend only used it a couple of times in 23 years he owned it.

When it is registered I will make up for that.

Regards

Paul

Previously richard_cornish wrote:

Hi again Paul,

The crankcases on your bike should be aluminium as the dull grey magnesium alloy ( known by it's commercial name Electron ) crankcases fitted to the Manx are significantly different to the Inter, although the barrel and head will still fit both. The ManxSOHC cambox on the other hand is a direct swap for the aluminium one and only needs the oil feed pipe tweaking. The bevel housings would have been aluminium originally as the magnesium ones were only fitted to the Manx and most likely have been fitted retrospectively to your engine and are also a straight swap. The head and barrel are correct for 1950, the full alloy heads came in for 1951. I am not sure when the bolt through oil tanks came in as they werelater than the petrol tanks so it could be original or may be another retro fitted item. The big advantage of magnesium alloy is that it weighs about 2 thirds of what the ordinary cast alloy does. Regards, Richard.

The Clubmans TT Inters with plunger frames [ from 1947-52] were often fitted with some Manx cycle parts [ front screen/rear mattress seat ] for the Clubmans TT race , and most discarded the lights and fitted a long straight exhaust pipe with no silencing . Most genuineClubman Inters I ve seen have a factory modified front brake plate with a small alloy air scoop and 4 air exit holes . Some of the Inters were designated as " Clubmans" in the factory Despatch records , others that competed in the Clubmans TT were not , and invariably those that were designated Clubmansbikes destined for the TT were despatched in May . In my view , I thinkit is likely that some of the Inters destined for the better riders were tuned to give better performance than the standard Inters , as winning the Clubmans TT was very good publicity .Sadly , the 350 and 500 Inters were no match for the BSA Gold Stars in the Clubmans TT, particularly later on , where their dominance became overwhelming , even when the Norton factory introduced the featherbed Inters .

Regards Bob Chapman