Engine / Components - Rotax MMH-912 Series Maintenance Manual

3.4)

Engine / Components

DESIGN:
BORE:
STROKE:
DISPLACEMENT:
CYLINDER:
PISTON:
CYLINDER HEAD:
COMPRESSION:
INTAKE VALVE:
EXHAUST VALVE:
VALVE CLEARANCE:
VALVE TRAIN:
CAMSHAFT:
CONTROL TIME:
(at 1 mm valve stroke):
CRANKSHAFT:
COOLING:
LUBRICATION:
OIL DELIVERY RATE: 1) Main oil pump:
912 A, F, UL
1)
912 S, ULS, ULSFR
2)
914 F, UL
3)
Effectivity 912/914 Series
Edition 1 / Rev. 3
BRP-Powertrain
Maintenance Manual
4-cylinder horizontally opposed 4-stroke-engine
79.5 mm (3.13 in.)
61.0mm (2.40in.)
1211.2 cm³ 1352 cm³
1) 3)
Lightweight metal cylinder with Nikasil coated
running surface
Lightweight cast metal piston with 3 piston rings
4 individual cylinder heads
9 : 1 11.1 : 1
1) 3)
38 mm (1.49 in.), valve seat surface hardened
32 mm (1.26 in.) NIMONIC, armor welding at
valve seat
automatic compensation of clearance by hydraulic
valve tappets
OHV, hydraulic valve tappets, pushrods and rocker
arms
steel, annealed, liquid nitriding
lo. 0° T.D.C.
1) 3)
Ic. 48° after B.D.C.
Io. 2° before T.D.C. Oo. 48° before B.D.C.
2)
Ic. 48° after B.D.C.
supported in 5 plain bearings, case hardened
liquid cooled cylinder heads, ram air cooled cylinders
1) Main oil pump circuit:
Dry sump forced lubrication system, trochoid pump
driven by the camshaft, oil return by the blow-by
gases
2) Suction pump circuit:
Extra trochoid pump driven by the camshaft returns
oil from the lower oil sump of the turbocharger to
the oil tank
approx. 16 l/min. at 5500 rpm
2) Suction pump circuit:
approx. 4 l/min. at 5500 rpm
84 mm (3.31 in.)
1) 3)
2)
2)
Oo. 48° before B.D.C.
Oc. 0° T.D.C.
Oc. 2° after T.D.C.
3)
3)
71-00-00
October 01/2010
2)
page 12