Update September 2021: Out of stock, but new batch currently being manufactured - expected @Dec 2021. Order now to reserve a set, we may ask for £20 deposit.
This listing is for a complete headrace bearing set, to fit those Norton models fitted with telescopic forks - from approximately 1947 to 1957. Sorry, I am not an expert on later Featherbed roadgoing models and later twins - they may have continued to be the same type fitted to these models as well, so if you wish to fit these to a later model please email and we can provide dimensions.
The set consists of 4 hardened headrace bearings and two sets of ball bearings. Original Norton telescopic fork headraces (from Norton single 'Long' Roadholder forks) were used as the pattern for manufacturing these and all dimensions are the same to the originals.
The two frame races have a grease track and a small hole in the track, to allow for greasing from the frame. The 3rd one of this type fits on the base of the fork stem (this still has a hole in the track - but fits flush against base of the fork crown - so hole is blind). The fourth race does not have a greasing hole and the inner face of the bearing race is a larger diameter than the other 3 races. This is to allow the large crown nut shoulder used on telescopic forks to slide fit into this inner bearing race face - see accompanyning photograph.
It should be noted that between this top crown nut (which fits under the top stanchion crown) and the top headrace bearing is fitted a pressed steel cover, to stop dirt getting into the bearings. There were two types of covers and we can provide these as well if required - the normal deeper roadgoing type (Item 0872 in our catalog) and a shallower version on Manx Norton models (Item 0873).
As shown in the photographs bearing races are supplied with the ball race area smeared in Castrol moly grease to protect them from rusting in storage. I find this is also a good grease to use for headraces on assembly (note in some photographs 2 bags of balls are shown - but there is one bag supplied with enough balls for two races + 1 additional ball in case you lose one on assembly)
- To fit these races - you must first remove old races (often they can be tapped out with punches just reaching the inners faces of the old races on the frame or outer race on the fork stem. It is important to try and tap them out centrally to avoid damaging/opening out bearing housings any more than necessary
- When fitting new races, remove all traces of paint, rust or rough edges from the areas to receive the new races. For the fork stem, check the inner face is not marked or worn and try and ensure the new race is placed over centrally - ideally they should be a light tap on. To help with this the race can be warmed in an oven first. If the fork stem bearing face is worn or damaged - a small amount of bearing fit fluid may help to retain them (I have a couple of original tele forks columns and found slight differences in wear on both - as they are many years old), but our races are made with the same inner race diameter as the original hardened race diameter. On the steering stem in the photograph which has minimal wear, after cleaning the stem base and bearing retaining area, the bottom race went on with light taps with a rawhide mallet, tapping radially in turn, to ensure the race went on evenly
- For fitting headraces into frames - again, ensure receptor area is fully cleaned of rust and dirt first. It is important to ensure the greasing hole in the 3 races to go in frame and top crown are lined up with the relevent grease nipple holes - otherwise it will not be possible to grease them in future without stripping
- To fit these races into frame - I first place races into a freezer for an hour or so (to contract as much as possible) and then normally use a soft aluminum drift, as shown in the photo - to ensure an even pressure is applied to the entire bearing face. Do not hit bearing races directly with a hammer as this could damage them. When tapping them in ensure they are seated squarly and fully down on the bottom face. Pack races with clean grease on assembly