This listing is for a complete headrace bearing set, to fit those Norton models fitted with Norton girder forks - from approximately 1931 to those still being supplied with girder forks in 1946.
The set consists of 4 hardened headrace bearings and two sets of ball bearings. Original Norton girder fork headraces were used as the pattern for manufacturing these and all dimensions are the same.
Three of the races are identical and have a grease track and a small hole in the track, to allow for greasing from the frame and top crown grease nipples. This type are fitted to both sides of the top race (girder fork top crown and upper frame race), as well as the bottom race frame race.
The fourth race does not have a small hole, and this race is intended to be fitted to the base of the girder fork steering stem, as shown in one of the photographs (this is specific to the girder fork models - if you have a telescopic fork model see listing 0913). This race also has its inner face ground to the exact dimensions of original races.
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 girder 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 (this is not uncommon unfortunately, as original girder forks are now at least 75 years old)
- For fitting headraces into frames (or top crown) - 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 and top crown - 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