Month: February 2013

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Elliott Montagu’s 1927 Triumph N model restoration – Part 5

If you are contemplating restoring a machine it's best to make it as authentic as is reasonable. It will look and ride like it did when the new owner brought it home and proudly showed it to his family and his mates. You won't run into problems when licensing it and it may be more valuable. The Club defines an authentic machine as follows. The machine must consist of at least four or the original six major components that is engine, gearbox or transmission, frame, forks, petrol tank and wheels. To be classified as original the components must come from a machine of the same make and type, but not necessarily the same year provided that the model concerned was manufactured basically unchanged over a period of years. Faithful reproduction of two of the missing components is acceptable. Over the years tin ware like mudguards and tanks rust, controls and lighting components are removed, bikes get modified and bits get lost. You have to make them, get them made, swap or buy them. Reprinted parts books, pictures and the Club library are good sources for finding out what the parts you have to make or otherwise acquire look like. The handle bars that came with my bike were only fit for scrap. The original bars were 7/8th inch diameter with a bulge to 1inch at the centre where they fit onto the bike. I found a place that sells imperial size tubing. (They make roll cages for competition cars.) I turned up a 1inch sleeve and welded it to the centre of a straight bar. I made it known that I needed someone to bend the bars for me as I reckoned if I did it they wouldn't be recognisable as handle bars. A talented Club member and a slab of beer got me a "sporting and a touring handle bar." I chose to fit the touring bar. This Triumph came with either a lever throttle or a straight pulling twist grip control. When the twist grip option was chosen the bike came with a twin lever control to operate the choke and the ignition advance and retard. I had a twin lever control but one of the levers was broken off. It had Triumph stamped on it so it had to be resurrected. I found a 50's choke control in the Club store and with some modification it fitted…

Elliott Montagu’s 1927 Triumph N model restoration – Part 4

After months of trying to source an original clutch it became obvious that there just wasn't one available. A friend of mine in the Club said no worries we will make one. (I'm not naming people because I might forget someone who helped me). I had one component of the clutch and that was the splined 'clutch driving member' that fits the driven shaft of the gearbox. The clutch driving member also has a large diameter track to take the bearing on which the basket runs. I was fortunate to have this component as manufacturing it would entail machining splines and case hardening the bearing track. The basket that holds the clutch friction discs and clutch plates was spun. A flat steel disc of suitable thickness is retained in a lathe and as it turns the operator applies a tool with a long handle and bends the metal as it turns until the metal is shaped as in the picture. Slots are then cut to take the friction plate lugs. The first attempt using the spun basket didn't work too well. I welded a band around the basket to stop it opening up as pressure was applied during the operation of the clutch but the addition of this band caused some distortion and balance problems. The fix was to machine a basket out of a piece of large diameter aluminium bar. Another friend machined the basket and milled the slots to take the clutch plates. New AJS parts are used for the plates, the clutch springs are modern Triumph and rollers are used in the bearing. The clutch is driven from the engine via a chain wheel attached to the basket. The number of teeth that can be accommodated on the clutch chain wheel depends, to some degree, on the overall diameter of the clutch which itself is governed by the diameter of the clutch plates. The clutch and chain wheel and chain have to fit into the primary chain cover which is designed to accommodate fore and aft movement of the gearbox to allow tensioning of the primary chain. The unit had to be made to fit or else the primary chain case cover would need to be modified. My main consideration, however, was to keep the final ratio the same as the original bike. The ratio is all about how many times the engine crank shaft turns over…