Description

The Motorcycle Workshop Practice Manual (2nd. Edition) by Haynes, provides important and essential information for do-it-yourselfers on how to handle and use tools, fabrication of metal and plastic components, and how to tackle various common motorcycle repairs. This manual has been a bestseller here at The Motor Bookstore for many years, and it definitely deserves a place in the library of the serious home-based motorcycle mechanic.
Book Excerpt: Haynes Workshop Practice Manual ENGINE AND TRANSMISSION TASKS

OIL SEALS

As the name suggests oil seals are used to prevent the escape of fluids. They are used to seal round rotating shafts and bearings. In two-stroke engines they also act as a pressure seal particularly for maintaining crankcase pressure. They also have a secondary function preventing contamination of bearings by moisture and dirt.
OIL SEAL REMOVAL AND INSTALLATION
Oil seals should be renewed every time a component is dismantled. This is because the seal lips will become set to the sealing surface and will not necessarily reseal.

Oil seals can be pried out of position using a large flat-bladed screwdriver (see illustration). In the case of crankcase seals, check first that the seal is not lipped on the inside, preventing its removal with the crankcases joined.

New seals are usually installed with their marked face (containing the seal reference code) outwards and the spring side towards the fluid being retained. In certain cases, such as a two-stroke engine crankshaft seal, a double lipped seal may be used due to there being fluid or gas on each side of the joint.

Before installing a new seal, check that the shaft over which the seal is to be fitted and the location in the housing are free from burrs which could damage the seal.

Smear grease over the seal lips before assembly.

Use a bearing driver or socket which bears only on the outer hard edge of the seal to install it in the casing ? tapping on the inner edge will damage the sealing lip.

Oil seals will stiffen and dry up after long storage periods, leading to leakage. They should be renewed.

WHEELS AND TIRES

RENEWING WHEEL BEARINGS

A common arrangement for the wheel bearings on many machines is two ball bearings pressed into the central bore of the wheel hub. The bearings are located internally by either a tubular spacer or by the shoulders machined into the hub. The assembly is generally protected by one or more grease seals.

In the case of the rear wheel on a chain drive machine, there is often a third bearing carried in a detachable sprocket carrier and cush drive unit.

The above arrangement will be found on a large number of Japanese machines, where wheel bearing arrangements have become almost standardized. It is not possible to list all the various systems in detail in this book, and it follows that the appropriate workshop manual should be consulted to see which arrangement applies to your model.

Most shaft drive models use a similar method of attaching the rear wheel, the shaft and bearings forming part of the bevel drive assembly.

When checking wheel bearing play, first support the motorcycle so that the wheel is raised off the ground. Grasp the wheel in two diametrically opposite places and attempt to move it about the wheel axle (see illustration). Any play will be immediately obvious.

Occasionally, you may encounter a threaded bearing retainer at this stage. These require a special pin spanner to remove them, though in the absence of the correct tool you can often make up an improvised version from steel strip, drilling holes to correspond with those in the retainer and fitting small bolts to act as the locating pins. The accompanying line drawing shows an example of this type of tool. Always check the threads on the retainer before attempting removal; you may find that those on the right-hand side are left-handed.

Subject: Haynes motorcycle workshop practice manual. Tools, safety, part fabrication, engine, transmission, etc. ISBN-10: 1785213768| ISBN-13: 9781785213762| Haynes 3470

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