Mark’s General Tips

  • Battery terminals can cause trouble. Although the voltage they carry is quite small, the current a lead acid battery can produce is very high so it’s vital the battery is never short-circuited. For instance never be tempted to put a spanner down on the top of a battery, however careful you think you are. If the battery or its carrier are not quite as the manufacturer intended, you need to be careful that the seat pan (or anything else) cannot touch the terminals. Finally, when connecting the battery, it is safer to do the earth (ground) terminal last. When disconnecting do it first.

 

  • One great thing about the system for metric screw threads is that they are a universal standard. Or are they? There are different series for coarse, fine and extra fine threads, which have different thread pitches for the same nominal diameter, but there is also the question of the JIS system. JIS stands for Japanese Industrial Standard and was in use by the Japanese manufacturers until 1967. If you have a real museum piece, watch out for 3, 4, 5 and 12mm threads which have a coarser pitch for the JIS system.

 

  • If you arc changing your headstock bearings, you will need to remove the races from the frame, and the usual way to do this is to use a hammer and drift on the overhanging edges to knock them out. But, if the bearings are the taper roller type, the races seem to be designed to prevent this, as the simplest way to create an overhang is to run a ring of bead round with an arc welding set. This also has the effect of contracting the race to aid its removal.
Always get your bearings!

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