This is for a set of 4 lower bevel housing shims to fit later DOHC type housings that are fitted with 'coarse' bevel gears - these having a larger central hole than SOHC and early DOHC engines.
Essential when rebuilding your engine to ensure that the lower vertical bevel gear has the correct backlash and position in relation to the crankshaft bevel gear, these lower bevel shims fit between the timing case housing and the lower bevel housing - Fitted in conjunction with the timing case shim, the ideal positioning is acheved when the gears are in line and there is a just perceptable gap (backlash) between teeth.
We also sell the more normal SOHC lower bevel housing shim (fitted from 1930 to the mid 1950's to all SOHC engines and early longstroke DOHC engines, but later DOHC Manx Norton engines used coarse bevel gears and had a housing with a larger hole. These shims have that larger hole - this being a fraction larger than 51mm.
It was also not unheard of for earlier SOHC or DOHC crankcases to be modified to fit a later 'coarse bevel' housing, indeed it was for this reason that we originally had these shims made - I found a housing to fit an original SOHC Manx enginethat had been modified to take this larger hole.
If you are not sure what type of lower bevel housing you need - you can email us on firstname.lastname@example.org for more detail.
This set of shims consists of 4 shims in the following thicknesses:
0.030”/0.018”/ 0.012"/0.006" (metric equivalent: 0.5mm/0.3mm/0.2mm/0.1mm) - with a small cost saving over buying them separately.
Packed in Duck Oil to protect from rusting