Oil circuit — description (Triumph Rocket III)

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Triumph
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Rocket III
Engine and systems
Lube system
Oil circuit — description

Contents: General description ↓ Scavenge system ↓ Pressure system ↓

General description

The Rocket Ilf utilises a dry sump lubrication system whereby a pressure pump takes oil from an oil tank and delivers oil under pressure to the engine and transmission. A scavenge pump collects oil from the sump and returns it to the oil tank.

The oil tank is attached to the upper crankcase on the left hand side of the motorcycle. Situated within the lower crankcase, the pressure pump is gravity fed from the oil tank via an internal drilling. An oil tank drain plug is situated at the lowest point in the drilling, in the sump itself.

Scavenge system

Pickups from the double-ended scavenge pump collect oil from the front and rear of the sump and return it to the oil tank. Further drain plugs are fitted to the front and rear of the sump to drain residual oil from the sump.

Pressure system

From the pressure pump, the oil is delivered along an internal passage, past the oil pressure relief valve. The oil pressure relief valve relieves excess oil pressure by allowing oil to return to the sump. Once past the oil pressure relief valve, the pressurised oil goes through a one-way valve whose purpose is to prevent the oil in the tank from draining into the lower crankcase area.

From the one-way valve, the oil is passed through the oil filter. Filtered oil is fed directly to the main oil gallery for distribution. Drillings from the main oil gallery feed oil to the four crankshaft main bearings. There are also three piston oil jets, located in the main bearing housings which lubricate and cool the pistons.

(Information copied from this resource: MOTOINSTRUCTION.ru)

Oil is also fed from the main oil gallery, through internal drillings and pipes, to the transmission. The transmission input shaft is both drilled through its entire length and cross-drilled. The cross drillings provide oil directly to the gears, selector forks and bearings. Oil flowing through the centre of the shaft exits at the clutch end, to provide oil to the clutch assembly. A spray jet for the outside of the clutch is mounted directly to the pressure pump. The torsional damper shaft is also fed from the input shaft. The torsional damper shaft is cross-drilled to feed the gears, bushes and other running surfaces. An internal passageway carries oil to the output shaft bearing and then on to the output shaft. The output shaft is also cross-drilled to carry oil to the gears, selector forks and bearings.

The cylinder head is fed via an internal drilling coming from number 4 main bearing. Within the cylinder head, a passageway through the cam ladder feeds oil to the camshaft bearings, and spills oil onto the tappet buckets and the valves. Spill oil returns via the cam chain area to the sump, lubricating the cam chain in the process. Also located off the cylinder head supply is an oil jet which cools the alternator. The low oil pressure warning switch is located at the rear of the cylinder head.