Chain Care Part 2
This information was first published in 1961 by Renold Chains. It is still relevant for those restoring and riding old motorcycles today.
If you haven’t yet read our blog Chain Care Part 1, click here.
CHAIN AND CHAINWHEEL INSPECTION
It is rare to find anything wrong with the alignment of the chainwheels (sprockets) on a new machine, but it is possible for malalignment to occur in use. This may be due to a variety of causes such as slackened nuts, incorrect reassembly after say an emergency repair, or minor spills. A periodical alignment check is therefore desirable, and is most easily done when the machine is undergoing a minor overhaul, as removal of adjacent components facilitates the job.
A straight-edge across the sides of the teeth on the two chainwheels concerned should touch at four points, in any position of rotation of the chainwheels. If the latter are in correct alignment, the inner plates of the chain will be slightly polished equally on their inner sides, and this is not detrimental. However, if one side shows considerably more wear than the other, it indicates that the shafts are not parallel (as viewed from above), or not in the same plane (as viewed from the back of the machine).
If the inner plates on both sides of the chain show real wear, as opposed to polishing, and particularly if this is apparent after a comparatively short mileage, it is probable that one chainwheel is farther out on its shaft than the other. This could be due, for example, to wrong assembly of the engine-shaft shock absorber, or the clutch in the case of a primary drive, or to faulty assembly of the rear hub components, or incorrect rear wheel replacement in the case of the final drive.
Chainwheels (sprockets) which are excessively worn assume a “hooked” appearance.
Checking the alignment of the primary chainwheels
When they are replaced it is worthwhile checking the new ones for accuracy. A new chain should fit completely round the teeth with a snug fit, neither too slack nor having a tight “springy” feel. The chainwheel bore must be concentric, otherwise the chain will tend to slacken and tighten as the chainwheels are rotated.
With the chainwheel in position, a pointer fitted adjacent to the teeth edges will detect such faults, and if any show up, the chainwheel should be rejected, assuming of course that the wobble is not caused by a bent shaft. In any case, however, the fault must be corrected, otherwise the chain will wear unevenly and quickly.
The standard method of coupling a chain is by a spring connecting link, which is a simple and effective device. On normal touring machines it is completely reliable, but nevertheless should receive regular inspection.
It may be advisable on such machines to replace the spring link at say 5,000 mile intervals, the reason being that, of necessity, the detachable plate on this link has to be a free fit, and under heavy load some wear must occur, thus throwing an undue proportion of the load on to the opposite (fixed) plate of the link.
It is important to note that the closed end of the spring clip must point in the direction of chain travel.
Checking the runout of the engine chainwheel with the use of a pointer