Project Yamaha TX750 part 7: Electric Avenue!

Our Mark sorts out any electrical gremlins with the TX and finds that the system was fairly advanced for the time.

- MARK HAYCOCK

Time now to look at the electrics and there were no surprises here. The wiring was generally in pretty good shape apart from one or two points…

As long ago as the early 1970s, Japanese wiring systems were made to a very high standard compared with those which were typically found on contemporary British bikes, and despite the fact that they were designed to last for maybe 10 years or so, after nearly 50 years they usually are still capable of working satisfactorily.

In this case the problems were where the insulation had been damaged (Photo 1) or replaced by something slightly dodgy (Photo 2). The other issues were in the inevitable corrosion or oxidation which had occurred and was in effect insulating parts of connectors which were meant to be conductors of electricity: simply corrected by using a bit of wet and dry paper.

I carried out a few tests with a multimeter and found that the ignition switch seemed to have a higher resistance than it should have (i.e. it should be practically zero). Unfortunately, accessing the switch was a bit of a job as it is within the instrument assembly so I took the whole lot off as I also needed to sort out the wire groups where the insulating sleeves had fossilised and cracked (Photo 3). This also gave me the opportunity to replace one or two lamps which had failed.