Rotax 914 Series Maintenance Manual page 85

A compression tester is required to check compression. The compression
should be between 9 and 12 bar (130 and 174 psi).
PROCEDURE:
Bring engine to operating temperature (engine oil temperature between
30 to 70 °C (90 - 160 °F)). Unscrew and remove top spark plugs.
Press compression tester over the spark plug hole and use the starter to turn
the engine over with open throttle until maximum pressure is reached.
Successively take readings on all four cylinders and compare results.
Individual readings for the cylinders must not differ by more than 2 bar (29 psi).
If the value is below 6 bar (87 psi), inspection, repair or overhaul must be carried
out in accordance with the instructions for continued airworthiness.
- Detailed inspection of affected engine components.
Effectivity: 914 Series
Edition 1 / Rev. 0
BRP-Rotax
MAINTENANCE MANUAL
12-00-00
page 11
May. 01/07