Evolution of Honda CBR600F Engine (in the UK) Milestones in Honda Motorcycles and 4 Stroke Engine Development 1951 Dream model E 146cc, single cylinder. Air cooled, OHV. 1957 C71 / C76 250 / 305cc parallel twin. Air cooled, SOHC, dry sump, electric start. 1959 CB92 125cc parallel twin. Air cooled, SOHC, wet sump, electric start. 1965 CB450 450cc parallel twin. Air cooled, DOHC, wet sump, electric start. 1969 CB750 Four 750cc in-line four. Air cooled, SOHC, dry sump, electric start. 1971 CB500 Four Slightly smaller version of CB750. Air cooled, SOHC, wet sump. 1972 CB350 Four Honda’s smallest in-line four. Some say underpowered. 1975 CB400 Four Very popular but too expensive for Honda to make a commercial success. 1975 GL1000 Gold Wing Honda’s first liquid cooled flat four. SOHC. 1979 CB750 Four In-line four now has DOHC. 1982 VF750 Liquid cooled vee four. DOHC. 1987 CBR1000F Liquid cooled in-line four. DOHC. 1987 CBR600F Liquid cooled in-line four. DOHC. Conversion note : 1 kW = 1.34 hp = 1.36 PS

Yearly Changes in CBR600 F1 Engine 1987 CBR600F-H Original features were :- • 598cc, liquid cooled, in-line, four cylinder engine. • Sixteen valves, operated by double overhead camshafts, via a chain drive off the crankshaft. • Bore x Stroke = 63.0 x 48.0 mm • Compression ratio 11.0 : 1 • Engine output 85 bhp @ 11,000 rpm. • Engine torque 59 Nm @ 8,000 rpm. • Redline of 12,000 rpm. • Engine dry weight 63 kg. • Aluminium construction of the engine/gearbox with the crankcase split horizontally, holding a wet sump. • Six bearing crankshaft. • Pressure fed lubrication system from a chain driven trochoidal oil pump. • Separate oil cooler. • Alternator mounted on the right end of the crankshaft. • Starter clutch mounted on the left end of the crankshaft. • Water pump located on the left side of the crankcase and driven off the oil pump shaft. • Six speed constant mesh gearbox. • Wet, multi-plate clutch, gear driven from the crankshaft. Clutch had 6 friction plates. • Liquid cooling system :- thermostat, radiator, oil cooler and pump. • Electric fan aided radiator cooling when required. • Carburation :- four 32 mm CV carburettors, fed from the fuel tank via a strainer, fuel tap, filter and electric

fuel pump. • Electronic ignition system :- timing rotor (on the crankshaft), two ignition pulse generator coils, spark unit

and two ignition HT coils.

1988 model 1988 CBR600F-J No notable engine changes. 1989 CBR600F-K • Engine output raised by 8 bhp to 93 bhp @ 11,000 rpm. • Engine torque 62 Nm @ 10,500 rpm. • Revised cylinder head porting and valve timing. • Reshaped combustion chambers and pistons, resulting in a higher compression ratio of 11.3 : 1 • Small increase in carburettor size to 32.5 mm. 1990 CBR600F-L No notable engine changes.

Yearly Changes in CBR600 F2 Engine 1991 CBR600F-M • Engine redesigned to make it lighter and more compact. • Displacement now 599cc. • Engine output raised by 7 bhp to 100 bhp @12,000 rpm. • Engine torque 64 Nm @ 10,500 rpm. • Redline of 13,000 rpm. • Engine dry weight 61 kg. • Larger and lighter valves. • More over-square dimensions. Bore x Stroke = 63.0 x 48.0 mm • Lighter pistons. • Higher compression ratio of 11.6 : 1 • Stronger (and lighter) crankshaft. • Rocker arm actuation of valves changed to “shim under bucket”, resulting in maintenance intervals

altered from 5,000 to 12,000 miles. • Camshaft chain moved to the right end of the crankshaft, allowing one less crankshaft bearing to be

used i.e. now a five bearing crankshaft. • Liquid-cooled oil cooler incorporated in the engine. • Clutch reduced in diameter from 138 to 125mm. This and smaller primary gears allowed the gearbox

output shaft to be positioned 12mm closer to the crankshaft, allowing a more compact crankcase. To compensate for the smaller clutch, number of friction plates increased from 6 to 9.

• Larger airbox and carburettors increased to 34 mm.

1991 model (Benetton colours) 1992 CBR600F-N No notable engine changes. 1993 CBR600F-P No notable engine changes. 1994 CBR600F-R No notable engine changes.

Yearly Changes in CBR600 F3 Engine 1995 CBR600F-S • Engine output 73.5 kW (100 PS) @12,000 rpm. • Engine torque 64 Nm @ 10,500 rpm. • Combustion chambers reconfigured to give a higher compression ratio of 12 : 1 • Redline of 13,300 rpm. • Engine dry weight 62 kg. • Needle bearings in gearbox for better shifting. • Cooling improved with a curved radiator and bigger oil cooler. • New ram air intake system. • Carburettors increased to 36 mm. • New electronic 3D mapping on ignition control.

1995 engine

1996 CBR600F-T No notable engine changes. 1997 CBR600F-V • Engine modified. • Engine output up to 77 kW (105 PS) @ 12,000 rpm. • Engine torque 66 Nm @ 10,500 rpm. 1998 CBR600F-W No notable engine changes.

Yearly Changes in CBR600 F4 Engine 1999 CBR600F-X • Engine given a bigger bore and shorter stroke (67 x 42.5mm). • Engine output now 81 kW (110 PS) @ 12,500 rpm. • Engine torque 65 Nm @ 10,500 rpm. • Redline now at 13,500 rpm. • Reduction in engine internal weight and friction. • Engine dry weight 59 kg, lighter by some 3 kg. • Larger valves. • Cylinders have aluminium liners coated in graphite and ceramics for improved heat transfer and reduced

friction. • Other friction losses minimised by changes to valves, pistons and bearings. • Crankshaft journal diameter reduced from 33 to 30mm. • Crankshaft rotating mass increased for more torque at lower speeds. • More compact liquid-cooled oil cooler, located with oil filter. • Engine crankcase designed to share swing-arm pivot. • Shorter, lighter starter motor. • More compact, lighter clutch, with number of friction plates reduced from 9 to 7. • Taller radiator. • Small increase in carburettor size to 36.5 mm. • New ignition system. Ignition coils built into spark plug caps. Engine outline showing old and new (shaded)

1999 engine 2000 CBR600F-Y No notable engine changes.

CBR600 F4i Engine 2001 CBR600F-1 Final features were :- • 599cc, liquid cooled, in-line, four cylinder engine. • Sixteen valves, operated by double overhead camshafts, via a chain drive off the crankshaft. • Bore x Stroke = 67.0 x 42.5 mm • Compression ratio 12.0 : 1 • Engine output 81 kW (110 PS) @ 12,500 rpm. • Engine torque 65 Nm @10,500 rpm. • Redline of 14,200 rpm. • Engine dry weight 59 kg. • Aluminium construction of the engine/gearbox with the crankcase split horizontally, holding a wet sump. • Five bearing crankshaft. • Pressure fed lubrication system from a chain driven trochoidal oil pump. • Alternator mounted on the left end of the crankshaft, with the starter clutch mounted behind it. • Ignition timing rotor mounted on the right end of the crankshaft. • Water pump located on the left side of the crankcase and driven off the oil pump shaft. • Six speed constant mesh gearbox. • Wet, multi-plate clutch, gear driven from the crankshaft. Clutch had 7 friction plates. • Liquid cooling system :- thermostat, radiator, oil cooler and pump. • Electric fan aided radiator cooling when required. • Carburation by a programmed fuel injection system. The engine management had an electronic control

module that operated both the injection and ignition systems. • Fuel pump, contained in the fuel tank, pressurised a fuel rail on the throttle body assembly, via a filter,

and a pressure regulator returned excess fuel to the tank. • Alternator output increased from 343 W to 433 W, mainly to service the new fuel pump needs. • Electronic ignition system :- timing rotor (on the crankshaft), ignition pulse generator coil, throttle position

sensor, ignition control unit and four ignition HT coils (in the spark plug cap). • Spark plugs with a pointed, iridium-coated centre electrode.

2001 fuel-injected engine and the aluminium frame

Closer look at the 2001 engine

2001 fuel injection assembly 2001 air intake