Oil seal

Seal size is given as inner diameter × outer diameter × width (e.g. 20 × 32 × 6 mm). The seals most often replaced on a motorcycle are fork seals, crankshaft seals, shift and output shaft seals and water pump seals.

• Fit the seal with the lip facing the right way, using a suitable seal driver.
• If the shaft surface is scratched or pitted, a new seal will leak too.
• In Turkish it is also called "simering", after a common brand name.