This is the Works 'Smooth' type SOHC outer timing cover fitted to Norton International and Manx models from 1938 onwards, with provision for a rev clock - but this type are the rare 'Works' version in magnesium.
This version is the sports\racing version that has a rev clock boss cast in (generally considered the most desirable type). This type was fitted as standard on pre-featherbed Manx Nortons, but was often seen fitted to Norton Internationals, if wanting to fit a rev clock.
These versions have been faithfully replicated from an original pattrn, even including the original casting number and inner webbing. However, this version is manufactured in magnesium, which is a replica of the ultra rare type occasionally seen on the Works bikes in the late 1930's-1940's. Being manufactured in heat treated AZ91E magnesium alloy, they are also very light when compared to their aluminium alloy counterparts!
These magnesium versions are re-chromated after CNC machining to provide protection to the machined faces. They come lightly sprayed in duck oil to ensure they do not corrode in storage. 3\16" BSF screws should be used for the rev clock fitting (which we can also supply). However, if you wish to fit one of these but do not currently have a suitable rev clock, we also sell a very pretty stainless steel lasercut inspection cover, that can be fitted in place of a rev clock and also look the part.
Note: in the photos these covers look slightly wet. This is the protective water repellent oil we spray them in before placing them in a plastic sealable bags.
3\16" BSF screws are used to attach the rev clock gearbox to the timing cover (Item 0974) and we supply a pair with every timing cover purchased.
01/03/2020 Update: We are pleased to be able another small batch of these magnesium alloy outer timing covers - having sold out on the original batch quickly after we last offered them 6 years ago. However, sorry to say, the cost of magnesium alloy foundry costs has risen out of all proportinon to normal alloy since that time. We only use the best quality foundry (who cater to the motor racing and aerospace industry) - and all machining is by our regular CNC partner. After machining we then fully re-chromate them - before spraying and packing in Duck Oil, so although not cheap, we believe they are a high quality item, reflecting that cost.