1901-1953 Indian Motorcycle – Parts – Accessories

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  5. 104 – 1939-1940 Indian Four Piston Ring Assembly, Gasoline Tank Caps


Indian Four pistons are fitted with two 1/16 piston rings in the two top ring grooves. The two lower ring grooves are fitted with 3/32″ bevel rings, the bevel on ring pointing to top of piston. This gives an oil scraping effect on cylinder wall, returning surplus oil through the holes in piston just under each bevel ring.

The use of a piston ring compressor eliminates possible oil ring breakage when assembling cylinders.


Pressure in tanks and insufficient flow of gas to carburetor causing carburetor mixture to lean off at high speed effecting open throttle performance. Through one of the holes in bottom of gas cap, hook out and coil of spring that supports cap needle valve and cut off one to one and half coils of this spring. This will allow more air to vent through tank cap,

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