12.3 Valve components

% ^ ^

11 Valves/valve seats/valve guides - servicing

valves and related components can be done (if the necessary special tools are available) by the home mechanic. This way no expense is incurred if the inspection reveals that overhaul is not required at this time.

1. Because of the complex nature of this job and the special tools and equipment required, most owners leave servicing of the valves, valve seats and valve guides to a professional.

2. The home mechanic can, however, remove the valves from the cylinder head, clean and check the components for wear and assess the extent of the work needed, and, unless a valve service is required, grind in the valves (see Section 12).

3. A Honda dealer or motorcycle engineer will remove the valves and springs, renew the valves and guides, recut the valve seats, check and renew the valve springs, spring retainers and collets (as necessary), renew the valve seals and reassemble the valve components.

4. After the valve service has been performed, the head will be in like-new condition. When the head is returned, be sure to clean it again very thoroughly before installation on the engine to remove any metal particles or abrasive grit that may still be present from the valve service operations. Use compressed air, if available, to blow out all the holes and passages.

2 To disassemble the valve components without the risk of damaging them, a valve spring compressor is absolutely necessary.

Disassembly

3. Before proceeding, arrange to label and store the valves along with their related components in such a way that they can be returned to their original locations without getting mixed up (see illustration). A good way to do this is to use the same container as the followers and shims are stored in (see Section 10), or obtain a separate container which is divided into eight compartments, and label each compartment with the identity of the valve which will be stored in it (ie number of cylinder, inlet or exhaust valve, inner or outer valve). Alternatively, labelled plastic bags will do just as well.

4. If not already done, clean all traces of old gasket material from the cylinder head. If a scraper is used, take care not to scratch or gouge the soft aluminium.

12 Cylinder head and valves -

disassembly, inspection and reassembly

12.5c Remove the spring retainer .

1 As mentioned in the previous section, valve servicing, valve seat re-cutting and valve guide renewal should be left to a Honda dealer or motorcycle engineer. However, disassembly, cleaning and inspection of the

12.5b ... and remove the collets as described

hint

I Refer to Tools and Workshop Tips for details of gasket removal methods.

12.5d ... the valve spring ...

5 Compress the valve spring on the first valve with a spring compressor, making sure it is correctly located onto each end of the valve assembly (see illustration). Do not compress the springs any more than is absolutely necessary and take care not to mark the surface of the cam follower hole with the spring compressor. Remove the collets, using either needle-nose pliers, tweezers, a magnet or a screwdriver with a dab of grease on it (see illustration). Carefully release the valve spring compressor and remove the spring retainer, noting which way up it fits, the spring, the spring seat, and the valve from the head (see illustrations). If the valve binds in the guide (won't pull through), push it back

2»18 Engine, clutch and transmission

I2.5e ... and the valve spring seat

into the head and deburr the area around the collet groove with a very fine file or whetstone (see illustration).