As far as servicing intervals are concerned, the motorcycle has no chance compared with the motor car, as far as the costs are concerned there is more similarity. The latter is probably not as much due to the wages and amount of time spent, but rather, with the materials used. There is still a lot of work done by hand and little computer application in motorcycle service. This is due to the necessary valve adjusting and the still wide-spread multiple carburettor equipment. Nowadays, all in all, the motorcycle is a little easier to service than it used to be because the maintainance work is being taken more into consideration during the construction. Perhaps there will be even more changes when in the near future, the exhaust emission check becomes necessary.
How it works
The visual inspection with two-wheeled vehicles, is even more important than with four-wheelers, because of, e.g., the welding seams on the frame and possibly, a look at the spark plugs and inside the cylinder. In addition, there are substantially more lubrication points (e.g., also in the drive section), and the tightening of bolts/screws is still a large part of the inspection. With the Bowden cables, even the combination of lubrication and adjusting is required.
Motor cars today, are almost all fitted with a hydraulic valve clearance adjustment. This is different with motorcycles, here, the valve clearance setting still sometimes requires working with a micrometer and the removal and installation of the camshaft(s). Thereby, it's not always easy to reach the parts or the respective index markings. In addition, the to 1/100mm accuracy of the measuring instruments requires meticulous use and skill with the adherence to the tolerances. The correction of the valve clearance is generally also not as simple as it appears in the above figure. Apart from bucket-tappets whose flat shims have to be replaced, there are also cam followers with cup-shaped shims.
While the ignition requires little attention, except perhaps the prescribed spark-plug change, as with the motor car, this is generally different with the fuel/air mixture processing. Not only must the throttle valves of fuel injection systems, be synchronised, but with several carburettors, additional work is still to be done, e.g., the idling setting. As far as the treatment of the filters and the oil goes, both vehicle types are once again, similar, apart from the smaller dimensions, which make shorter changing intervals necessary.
function of the frame and suspension is even more important for motorcyclists than it is for car drivers. These are also more sensitive as a rule, and make use of - rightly or wrongly - numerous set-up possibilities. Thus the motorcycle mechanic must examine, not only all the components (e.g., the steering bearing) for their individual or collective freedom of movement, he should also, in a final test run, check all the settings, and perhaps discuss this with the customer.
Work on the brakes of cars and bikes is once again, very similar. It is practical that with motorcycles, the brake fluid is often only changed when, through measuring the moisture content, is is actually necessary, and not automatically. 12/09