Measure the cylinder bore in the directions shown with a telescoping gauge

the average cylinder dimension at each point (see illustration).Compare the results to the specifications at the beginning of this Chapter. If the cylinders are worn, oval or tapered beyond the service limit, or badly scratched, scuffed or scored, the cylinder block must be rebored. Oversize pistons are available (see Section 23).

12 If the precision measuring tools are not available, take the upper crankcase to a Honda dealer or motorcycle engineer for assessment and advice.

13If the cylinders are in good condition and the piston-to-bore clearance is within specifications, the cylinders should be honed (de-glazed). To perform this operation you will need the proper size flexible hone with fine stones, or a bottle-brush type hone, plenty of light oil or honing oil, some clean rags and an electric drill motor.

14 Clamp the block/crankcase securely so that the bores are horizontal rather than vertical. Mount the hone in a drill motor, compress the stones and insert the hone into the cylinder. Thoroughly lubricate the cylinder, then turn on the drill and move the hone up and down in the cylinder at a pace which produces a fine cross-hatch pattern on the cylinder wall with the lines intersecting at an angle of approximately 60°. Be sure to use plenty of lubricant and do not take off any more material than is necessary to produce the desired effect. Do not withdraw the hone from the cylinder while it is still turning. Switch off the drill and continue to move it up and down in the cylinder until it has stopped turning, then compress the stones and withdraw the hone. Wipe the oil from the cylinder and repeat the procedure on the

other cylinder. Remember, do not take too much material from the cylinder wall.

15 Wash the cylinders thoroughly with warm soapy water to remove all traces of the abrasive grit produced during the honing operation. Be sure to run a brush through the oil and coolant passages and flush them with running water. After rinsing, dry the cylinders thoroughly and apply a thin coat of light, rust-preventative oil to all machined surfaces.

16 If you do not have the equipment or desire to perform the honing operation, take the block to a Honda dealer or motorcycle engineer.

32 Initial start-up after overhaul

1 Make sure the engine oil level and coolant level are correct (see Daily (pre-ride) checks). Turn the fuel tap to the OFF position.

2 Pull the plug caps off the spark plugs and insert a spare spark plug into each cap. Position the spare plugs so that their bodies are earthed (grounded) against the engine. Turn on the ignition switch and crank the engine over with the starter until the oil pressure warning light goes off (which indicates that oil pressure exists). Turn off the ignition. Remove the spare spark plugs and reconnect the plug caps.

3 Make sure there is fuel in the tank, then turn the fuel tap to the ON or RES position as required, and set the choke.

4 Start the engine and allow it to run at a moderately fast idle until it reaches operating temperature.

Warning: If the oil pressureindicator light doesn't go off, or it comes on while the engine is running, stop the engine immediately and refer to Chapter 1, Section 33 for the oil pressure checking procedure.

5Check carefully that there are no oil or coolant leaks and make sure the transmission and controls, especially the brakes, function properly before road testing the machine. Refer to Section 33 for the recommended running-in procedure.

6 Upon completion of the road test, and after the engine has cooled down completely, recheck the valve clearances (see Chapter 1) and check the engine oil and coolant levels (see Daily (pre-ride) checks).

33 Recommended running-in procedure

1 Treat the machine gently for the first few miles to make sure oil has circulated throughout the engine and any new parts installed have started to seat.

2 Even greater care is necessary if new pistons/rings or new crankshaft or connecting rod bearings have been installed. This means greater use of the transmission and a restraining hand on the throttle until at least 600 miles (1000 km) have been covered. There's no point in keeping to any set road speed - the main idea is to keep from labouring the engine and to gradually increase performance up to the 1000 mile (1600 km) mark. These recommendations can be lessened when only a partial overhaul has been done, although it depends on the nature of the work carried out and which components have been renewed. Experience is the best guide, since it's easy to tell when an engine is running freely. The table below showing maximum engine speed limitations, which Honda provide for new motorcycles, can be used as a guide.

3 If a lubrication failure is suspected, stop the engine immediately and try to find the cause. If an engine is run without oil, even for a short period of time, severe damage will occur.

3-1

Chapter 3

Cooling system

Contents

Coolant hoses - removal and installation ................................ 9

Coolant level check ................................ see Daily (pre-ride) checks

Coolant reservoir - removal and installation.............................. 3

Coolant temperature gauge and sensor - check and

replacement................................................................................ 5

Cooling fan and cooling fan switch - check and replacement ...... 4

Cooling system checks ............................................. see Chapter 1

Cooling system draining, flushing and refilling ..... see Chapter 1

General information........................................................................... 1

Pressure cap - check ...................................................................... 2

Radiator - removal and installation.................................................. 7

Thermostat and thermostat housing - removal,

check and installation .............................................................. 6

Water pump - check, removal and installation............................ 8

Degrees of difficulty

Easy,suitable for novice with little experience

Fairly easy,suitable for beginner with some experience

*j

Fairly difficult,|k

suitable for competent >a^
DIY mechanic ||S

Difficult,suitable for ^
experienced DIY ^
mechanic 2S

Very difficult,

suitable for expert DIY ^
or professional JS

Specifications

Note: Where applicable, models are identified by their production code letter - refer to 'Identification numbers' at the front of this manual for details.

Coolant

Mixture type and capacity ................................................................ 50% distilled water, 50% corrosion inhibited ethylene glycol anti­
freeze

Pressure cap

Cap valve opening pressure................................................................. 16 to 20 psi (1.1 to 1.4 Bar)

Fan switch

Cooling fan cut-in temperature......................................................... 98 to 102°C

Cooling fan cut-out temperature ..................................................... 93 to 97°C

Coolant temperature sensor

Resistance

® 50°C ........................................................................................... 133 to 179 ohms

@ 80°C .............................................................................................. 47 to 57 ohms

@ 120°C ............................................................................................. 14 to 18 ohms

Thermostat

Opening temperature............................................................................. 80 to 84"C

Valve lift ................................................................................................ ... 8 mm (min) @ 95°C

Torque settings

Cooling fan switch ............................................................................... 18 Nm

Coolant filler neck-to-thermostat housing bolts................................. 12 Nm

Coolant temperature sender................................................................. 9 Nm

Radiator mounting bolt...................................................................... 12 Nm

Reservoir tank mounting bolt............................................................... 12 Nm

Thermostat housing cover bolts.......................................................... 12 Nm

Water pump drain bolt ......................................................................... 12 Nm

Water pump body-to-crankcase bolts.................................................. 9 Nm

Water pump cover bolts........................................................................ 12 Nm

3*2 Cooling system

1 General information

The cooling system uses a water/antifreeze coolant to carry away excess energy in the form of heat. The cylinders are surrounded by a water jacket from which the heated coolant is circulated by thermo-syphonic action in conjunction with a water pump, driven by the oil pump. The hot coolant passes upwards to the thermostat and through to the radiator. The coolant then flows across the radiator core, where it is cooled by the passing air, to the water pump and back to the engine where the cycle is repeated.

A thermostat is fitted in the system to prevent the coolant flowing through the radiator when the engine is cold, therefore accelerating the speed at which the engine reaches normal operating temperature. A coolant temperature sender mounted in the thermostat housing transmits to thetemperature gauge on the instrument panel. A thermostatically-controlled cooling fan isfitted behind the radiator to aid cooling in extreme conditions.

The complete cooling system is partially sealed and pressurised, the pressure being controlled by a spring-loaded valve contained in the spring-loaded pressure cap. By pressurising the coolant the boiling point is raised, preventing premature boiling in adverse conditions. The overflow pipe from the system is connected to a reservoir into which excess coolant is expelled under pressure. The discharged coolant automatically returns to the radiator when the engine cools.

Coolant is routed from a union at the back of the cylinder head to the carburettors to prevent icing in extreme conditions and is returned via a hose to the water pump.

Warning: Do not remove the pressure cap from the filler neck when the engine is hot. Scalding hot coolant and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, place a thick rag, like a towel, over the pressure cap; slowly rotate the cap anthclockwise to the first stop. This procedure allows any residual pressure to escape. When the steam has stopped escaping, press down on the cap while turning it anti-clockwise and remove it. Warning: Do not allow antifreeze to come in contact with your skin or painted surfaces of the motorcycle. Rinse off any spills immediately with plenty of water. Antifreeze is highly toxic if ingested. Never leave antifreeze lying around in an open container or in puddles on the floor; children and pets are attracted by its sweet smell and may drink it. Check with the local authorities about disposing of used antifreeze. Many communities will have

Date: 2016-01-14; view: 500