Copper washers for British motorcycles
Copper washers are used on almost every vintage British motorcycle. The sizes that were used were Imperial (inch) sized, and sometimes can be hard to find in a metric dominated world. These are the most common sizes used for rocker oil feed, drain plugs, and oil lines.
Copper is an excellent conductor of heat and electricity, and these soft, high quality made in USA washers are ready to use. Keep a few in your toolbox as they are not usually sourced locally anymore.
The 1/4 inch inside diameter washers are part number 70-2441, or E2441, also D403F, and 60-7132.
The 5/16 inch inside diameter washers are part number 82-1880, or F1880, 70-3249, and 06-7522.
The 3/8 inside diameter washers are part number 70-1335, or E1335, also 04-0606, 40-0159.