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The Unapproachable Norton

Manx Norton 500cc and 1959 International For Sale

Norton Motors didn't actually make any Inters in 1959, so this will tell you that this machine is not entirely kosher. The engine of this Inter was made in 1956, which is towards the end of the production of this machine. Production had slowed to a trickle, and at this time the bike was no longer listed, but was hand built to special order, mostly for club racing. Many of the parts were actually Manx, as the factory used up what stocks of parts they had available. About twenty machines were made in 1957, and a few in 1958 when production ceased.

I purchased the engine in 1966, someone had been racing it, but I don't know at what point it became separated from its frame. I purchased a 1959 Model 50 from a fellow apprentice, and thus the project was born. Most featherbed Inters that have been created by putting an Inter engine into a Dominator or ES2 / Mod 50 frame use an older iron engine. The more powerful all alloy featherbed Inter engine was only introduced in 1953, and most of them remain in their original frames. My engine is a genuine featherbed engine, so mine has been reunited with a featherbed frame, which is very similar to the original. It even has a flat on the RH top tube to clear the camshaft restrictor jet nut.

I first put the bike on the road in the mid seventies. I had fitted lots of featherbed Manx parts to it, including the seat, and clip-on handlebars. This was not very comfortable for road use, and I decided to rebuild the bike which was finally completed in 2005.

The engine is standard Inter. The engine castings were all good. I fitted a new Ransome & Marles big end, and trued and balanced the flywheels to 70 per cent...

The carburettor is an 1 3/32" Amal TT. It has been bored to take an oversize slide, and I have a spare oversize slide. I have fitted a Tufnol spacer with a polished aluminium sleeve between the carb and the head. Carb settings are: Main Jet 360, Needle Jet 109, Needle Position 3, Throttle Slide Cutaway 6.

The magneto is a BTH KD1 TT replica, identical to the one fitted to my Manx. It has been reconditioned by Independent Ignition Supplies to the same standard as the Manx one. It has new platinum points etc. Ignition timing is 38 degrees BTDC.

The frame is standard except for a few small changes. I have welded on plates for attaching the rear racing numbers, and also added a frame loop at the rear of the frame which provides an integral rear mudguard stay. I made a substantial fabricated steel head steady which looks far more robust than the original item. I had this plated. I drilled the rear frame gussets and fitted featherbed Manx style footrests in the same position as on a Manx. I left the rear brake as standard. (A 7" full width single leading shoe). I have used a replica cast Manx brake pedal. The lever was extended to improve leverage ratio, and both items were chromed.

I bought a genuine Norton twin leading shoe brake plate for the front brake, which is an 8" full width hub. When set up correctly and with new linings this proved to be a perfectly adequate brake for the performance and weight of the bike. I fitted Manx replica rear suspension units from Alf Hagon, but fitted softer springs as I found the ride a bit hard. (probably because the bike is so light) I had the front fork stanchions hard chromed and ground and fitted Manx springs from Summerfield. I fitted taper roller head bearings, and a genuine Manx Norton steering damper.

The gearbox is a Petty PGT 5 speed, which I bought from Ray Petty in the 1970's. I have used a replica Manx gear lever linkage. This does mean that the bike has to be bump started, but the light weight of the bike makes this fairly easy. If a purchaser wished to fit a kickstart gearbox, I have an AMC box which I could supply, with various gearing options, but it would mean getting a new exhaust pipe bent, and having a folding footrest etc. I have fitted a four plate clutch, and a standard primary chaincase.

I made a seat base and had it professionally upholstered, and I was very pleased with the result, which is very comfortable. I made some special very long swan neck clip-on handlebars, and with the position of the footrests gives a riding position which I find ideal. I fitted genuine Amal cast alloy handlebar levers with adjusters, and used genuine Manx pressed steel levers for the choke and ignition. The revcounter and speedometer are housed in featherbed Manx anti-vibration mounts, which are surprisingly effective, and I have fitted a 0-15 psi oil pressure gauge. I also fitted a handlebar mirror. I had an old Stadium mirror which had a pleasing oval shape, and seemed to suit the bike perfectly, so I had the back chromed, and had a new mirror glass made.

- one of two superb roadgoing cammy Nortons for sale.

I made the engine plates from 5/16" thick aircraft spec aluminium alloy, and finished them with an engine-turned effect. I bought a replica Manx 5 gallon petrol tank from Ray Petty, and a second hand central oiltank of the correct period. I ran the breathers back into a pot, as I had done on the Manx.

I took the bike up to Competition Fabrications and had an exhaust pipe bent, and bought a replica BSA Gold Star silencer from Armours. I had the wheels rebuilt using 19" Borrani rims, and fitted an Avon Roadrunner AM20 to the front, and an Avon Supervenom AM18 to the rear. Both in road compound.

I also made all the fasteners for this bike, including the front wheel spindle, pipe unions, etc, but unlike when I made them for my Manx, I felt that because the bike was not a completely standard Inter, I had some license to use modern materials. I made the wheel nuts, bevel housing gland nuts, and some other items in HE30 aluminium alloy to help keep the weight down, but everything else was made in Type 303 Stainless Steel. The shape of the bolt heads was different on the featherbed Manxes, with a larger size hexagon which was shallower, and faced off flat.

I have not felt the need to put this bike on a rolling road, as the carburetion seems to be very good, with no flat spots. The TT carb is easier to tune than the RN.

Sources


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