Single shim washer to fit Norton Upright/Laydown gearbox mainshaft or the layshaft of racing gearbox's. Useful if you have endplay or your gears are not fully in line.
Update Feb 20: Now available in 3 sizes: 0.030”/0.018”/ 0.012", (metric equivalent: 0.5mm/0.3mm/0.2mm) - please state which size you require when placing online order. Now also available as a set of 3 shims - Item 0405S.
It is not unusual to have some play or drag on a Norton clutch. This is often caused by a worn thrustwasher (which we also sell - see Item 0641) or sometimes just because a gear has become worn or assembled from parts of different years.
Therefore these shims can be a useful addition to take up small amounts of endplay. To measure endplay on most Norton gearbox's - check the outer cover with bearings fitted - often the bearings will be flush with the casing gasket face (but if not use a digital depth gauge to measure the + or - difference and make a note of this). Then on the main gearbox casting, with gears fitted and pushed up against the opposite wall fully, place a ruler across the casting - and check if there is a gap between the ruler and first gear shoulder of the mainshaft. If there is, and the gap (with any +/- difference of the outer bearing against front casting taken into account) is 20 thou or more, then this shim can be used to take up end float. Please note - you should always carefully check rotation of the shaft when tightening up the gearbox end nuts - if the shaft rotation tightens as the nuts are tightening, you may have negative clearance - in which case stripdown and find out what is causing it.
Note: always check the other gears for faults first, and particularly look to see if the bronze thrust washer that fits on the mainshaft up against the sleeve gear is not excessively worn - as this can also result in excessive end float - see the information given in Item 641's listing and replace this thrustwasher first.
Final note - This shim will also fit the layshaft endcover end on racing (i.e. M30 or Manx gearbox's, where no kickstarter is fitted) - to achieve a similar purpose if excessive float or uneven gear meshing exists.