30.16B ... Then slide the selector drum into place

22. Install the gearchange mechanism (see Section 19) and check gearchange operation while turning the input shaft.

23. Refit the oil sump (see Section 18) and the clutch (see Section 15)

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31 Crankcase halves and cylinder bores - inspection and servicing

Crankcase halves

1. After the crankcase halves have been separated, remove the crankshaft, connecting rods and pistons, transmission shafts, selector drum and forks, and, if required, the oil pressure switch, neutral switch and cooling system union, referring to the relevant Sections of this Chapter, to Chapter 9 for the oil pressure switch and neutral switch, and to Chapter 3 for the coolant union.

2. The crankcases should be cleaned thoroughly with solvent and dried with compressed air. All oil passages should be blown out with compressed air.

3. Inspect the bearing seats for signs of damage, especially if an engine or transmission bearing has overheated or seized (see Section 21). If bearing shells or a ball bearing cage are not a precise fit in their seats, ask your Honda dealer for a suitable bearing locking compound which will overcome small amounts of wear. Otherwise the crankcase halves will have to be renewed as a set.

4. All traces of old gasket sealant should be removed from the mating surfaces. Minor damage to the surfaces can be cleaned up with a fine sharpening stone or grindstone. Caution: Be very careful not to nick or gouge the crankcase mating surfaces or oil leaks will result. Check both crankcase halves very carefully for cracks and other damage.

5. Small cracks or holes in aluminium castings may be repaired with an epoxy resin adhesive as a temporary measure. Permanent repairs can only be effected by argon-arc welding, and only a specialist in this process Is in a position to advise on the economy or practical

31.9 Inspect the cylinder walls for scratches and scoring

aspect of such a repair. Note that there are, however, kits available for low temperature welding. If any damage is found that can't be repaired, renew the crankcase halves as a set.

6. Damaged threads can be economically reclaimed using a thread insert, which is easily fitted after drilling and re-tapping the affected thread. There are a few types of thread insert available, of varying quality and cost.

7. Sheared studs or bolts can usually be removed with stud or screw extractors. A stud extractor should be used if part of the stud is above the surface. Otherwise use a screw extractor, which consists of a tapered, left thread screw of very hard steel. These are inserted into a hole pre-drilled centrally in the stud, and usually succeed in dislodging the most stubborn stud or screw.

Refer to Tools and Workshop I Tips for details of installing a HilUl | thread insert and using screw extractors.

8 Install all components and assemblies, referring to the relevant Sections of this Chapter and to Chapters 9 and 3, before reassembling the crankcase halves.

Cylinder bores

9 Check the cylinder walls carefully for scratches and score marks (see illustration).

10. Using a precision straight-edge and a feeler gauge set to the warpage limit listed in the specifications at the beginning of this Chapter, check the block gasket mating surface for warpage. Refer to 7bo/s and Workshop Tips in the Reference section for details of how to use the straight-edge. It warpage is excessive the block/crankcase must be renewed.

11. Using telescoping gauges and a micrometer (see Tools and Workshop Tips). check the dimensions of each cylinder to assess the amount of wear, taper and ovality. Measure near the top (but below the level of the top piston ring at TDC), centre and bottom (but above the level of the oil ring at BDC) of the bore. Measure both parallel to and across the crankshaft axis in each case and calculate

Engine, clutch and transmission 2«55

Up to 600 miles (1000 km)	600 rpm max	Vary throttle position/speed
600 to 1000 miles (1000 to 1600 km)	8000 rpm max	Vary throttle position/speed. Use full throttle for short bursts
Over 1000 miles (1600 km)	10,500 rpm max	Do not exceed tachometer red line

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