This item is the 15 tooth magneto sprocket that is driven by the chain from the oil pump gear sprocket (SOHC models) or inlet cam (OHV, SV models), and fits on the end of the magneto shaft (either Lucas Magdyno or BTH KD1). These items are just the same in profile as original sprockets - the magneto sprocket being recessed, just as the original was - and is of the type fitted to almost all Norton single cylinder models from the 1930's to the late 1950's - i.e. SOHC, OHV and SV models
Price is Each.
We manufacture these sprockets in-house, on modern CNC machinery and to a very high standard. They are then hardened (the slight black, mottled finish is as a result of the hardening process). They are supplied sprayed in Duck Oil (the wet look in the photographs) to prevent rusting in storage.
They should fit most Norton singles from the late 1920's to the late 1950's - including SOHC models, OHV and Side Valve models. An original 'New Old Stock' Norton magneto sprocket was used to give the correct dimensions and as part of the manufacturing process we ensured they fit on both Lucas and BTH magnetos - as can be seen from the accompanyning photographs.
Although we are not experts on other marques - we believe this same sprocket design (and offset) may well have been used by other motorcycle marques of the 1930's-50's - particularly those models fitted with Lucas Magdyno units. If you require more information on these sprockets and offsets - you can email me at paul.norman@racingvincent.co.uk. We have certainly sold far more of this type over the years than we have the engine side magneto sprocket - so we can only assume a number of non-Norton customers are buying them!
We manufacture these sprockets in-house, and do not offer them to any other outlet, they are exclusive to ourselves. We used original Norton sprockets to ensure dimensions were as original, and the spocket tooth profile is the correct CNC generated profile for the imperial Renolds chain that we can also supply for most Norton single models.
Note: Fitting magneto sprockets - it is always best when fitting sprockets, to smear some fine grinding paste on the taper fit of the sprocket and gently grind the sprocket to the taper, to get a perfect fit. This is achieved when you have got a matt grey finish on both sprocket and taper. Ensure you fully remove the grinding paste before final fitting. Always use a 'puller' to remove the sprocket, do not try to lever the sprocket off with a screwdriver, as this will almost certainly damage the timing case. A tip when using puller's to remove sprockets - fit puller and screw central bolt until a good tension is reached, then give the end of the puller bolt a sharp sideways tap with a mallet - the jarring will easily loosen the sprocket
Update March 2024: Now back in stock - we have just had a new batch of these manufactured. See also Item 0392, the matching magneto side sprocket
