This matched set of camshaft bushings are direct replacements for the inlet and exhaust camshaft bushings specified for the unit-construction 1961-1969 C-range 350 and 500 models. 1970 and later T100 engines use the 70-3823 cam bush in both the inlet and exhaust positions.
The steel-backed bronze camshaft bushes are of the “split” variety and are manufactured in the UK to original specifications. The fitted bore diameter of the bushings is .8125″-.8135″. Outside diameter is .906″-.907″. The inlet cam bush is 1.094″-1.114″ long, while the exhaust cam bush is .922″-.942″.
The camshaft bushes support the camshafts on the drive-side of the crankcase. The 70-3824 inlet cam bush captures the timed breather disc, which works with the rotary breather valve to vent crankcase pressure through the inlet camshaft.
The cam bushes are pressed or drifted into the drive-side crankcase and require a .002″-.003″ interference fit. Camshaft bushes usually require honing to achieve the proper diametral clearance of .001″-.0025″ with the camshafts. Refer to the factory workshop manual for removal and installation instructions.
For 500 twins 1970 onward, 2 x 70-3823 are used, see recommended links to order that bush as pairs.