Roadholder 370 - October 2018

28 Henry Dulat of Surrey Branch gave a talk covering motorcycle electrics that are often seen by many as a 'black art', but that really it's not that difficult to understand. He went on to explain the workings of electrics to being rather akin to a water system, whether it be home plumbing with a header tank, or a canal system. The height of the header tank is the voltage and the amount of water flowing is the current. So a large pipe is like a fat wire in that it can allow more water to flow for a given head of water. A thin wire, like a thin pipe, would offer more resistance to the flow of current. Various metals are generally used for electrical conductors, with the better conductors including gold, silver, aluminium and copper. Generally, copper is used as being the best compromise for cost, flexibility and the ease of use. It is important that on a bike, all the current is made to flow along the wiring, and not be assumed to flow along the frame of the bike; there should not be any flow through the head bearings as this could cause a rapid deterioration. Alternators and dynamos generate electricity by spinning magnets or electromagnets as the magnetic field cuts through the generator coils. Both systems generate an AC voltage, though the dynamo converts this to DC voltage via the commutator, whereas the alternator requires an external rectifier. This generated voltage is related to the speed of the engine, so the higher the rpm the higher the voltage. Henry went on to discuss the sort of problems that come up with bad wiring, poor switches and also bad connections, especially of the crimped variety. Henry used a magnet and a piece of metal to pass through it and this demonstrated the magnetic pull of the field inside the magnet as the piece of metal passed through it. It also showed how much the rotating armature inside a dynamo and alternators has to overcome to be able to generate electricity. Also covered were ignition systems and how to obtain bigger and better sparks. Henry brought along many electrical items to demonstrate his talk, and also showed us how it all would work, in both practice and the theory. Our Club room was packed with very eager listeners who wanted to understand more about the electrics on their bikes so therefore making them perform so much better. Henry is always on hand to help those in dire need when the electrics on their bikes cause problems, often when leaving to go home. Can I thank Henry for taking the time and the effort to prepare his talk and coming along to demonstrate it all and to explain in basic terms how it would assist us all by getting better electrics for our bikes.Henry is the boffin for the Surrey Branch. electrics at surrey Anthony Curzon