How to Fit British Motorcycle Piston Rings
- 1). Remove the pistons from the engine and thoroughly clean them with a soft microfiber cloth. Do not use any harsh abrasives that could scour the surface of the pistons. Make sure you clear all the dirt from the grooves in which the rings will sit.
- 2). Install the lowest ring first. The make and model of your bike will determine the number of rings that fit to your piston, two to five rings on each one is the norm. Consult your parts dealer to find the appropriate size and type for your bike. There is usually at least one expander ring at the bottom, to prevent oil seepage, and at least one compression ring at the top, that creates a tight seal to compress the fuel and air.
- 3). Using the space cut in the ring, gently flex it outward as little as possible, taking care not to bend it. Slide it down from the top of the piston, until it sits in the appropriate groove. Check the seating of the ring in the groove, the ends either side of the cut should be almost touching. If the ring is slightly too large, it will be loose around the piston. If this is the case, remove the ring and use the file to take off any excess until the ring fits snugly around the piston.
- 4). Repeat the above process with all subsequent rings until they are all tightly seated in their appropriate grooves. Before installing the pistons back into the engine, cover them with a liberal coating of motor oil, to ensure all surface are properly lubricated before the engine is next started.
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