1977 GT500 – Refurbishing Components

I spent a couple of days recently refurbishing some of the sub-assemblies on the GT500 project bike. Still lots of little things to do, but it is starting to come together !

Previously I had taken the main wiring harness apart and re-sleeved it with new PVC black plastic sleeving and tape and now I wanted to replace the sleeving on a few of the smaller leads for the magneto, front brake stop switch and the left control switch. I normally buy sleeving from  Vintage Connections but they didn’t have the 10mm OD size I needed for the magneto lead. I finally tracked down what I was looking for at a place specialising in H-D wiring repairs and custom harnesses called 4RCustoms. Although what they had was in imperial measure, the 3/8 size was close enough to to the job – the critical issue being that the lead passed through a grommet and so it needed to be a tight fit to prevent water leaking past it.

On the T/GT500’s and of course many other bikes also, the magneto coils and in this case also the coils used for the electronic ignition, are soldered in, and given it had been quite a few years since I had wielded a soldering gun in anger, I took my time. Although the coils themselves checked out OK as far as ohmic value the fibre bushes on the side had disintegrated allowing the coils to flop back and forth on the armatures. As well, there were spots that were missing the insulating varnish so the copper was exposed – rather than take a chance and have to replace them later, I elected to just get it over with and replace all four coils used. The photo shows the completed job with the new sleeving installed.

Next I re-sleeved the engine stop switch on the right control switch. This is the same casting as used on other Suzuki’s of the same era, but is missing the hole and lettering for the starter button. I also rebuilt and re-sleeved the front brake stop switch. While this is available from Suzuki under a new part number 57460-33700, the new part is a ‘universal’ unit and so you get both the block and bullet electrical connector options. All that was wrong with mine was it needed new sleeving and for the leads to be re-soldered to the contact slide plate as seen in the photo above. The screws are 3mm and this is a case where the part number is incorrect as normally you can tell the length of the screws from the number 09125-03105  where the ’03’ gives the diameter and the ’10’ should give you the length. In this case they are actually 16mm long rather than 10mm.

The left switch assembly used in 1977 in Canada had the driving lights always on by default. This is done by using a modified on/off switch that has a tab preventing you from turning the lights off. I personally think this is dumb as when trying to start these things you need all the juice you can get, and interestingly you can still buy these from Suzuki – what they do still sell is the style used prior to 1977 which does allow you to turn the lights off – so I replaced the original seen in the photo above (as always – just ‘click’ to see a larger image) and to the right with the older style.

Next up was the oil injector pump.  This is a single piston style pimp, and quite a lot simpler than the one used on the Suzuki triples but also pretty robust. I was surprised that information specific to rebuilding these was hard to find, but the seals are all easily replaceable if you can find the correct sizes. The photo to the left shows the disassembled pump (just ‘click’ to see a larger version). I had trouble locating 1/2 mm sizes locally, but after a bit of searching found a place in the USA called MFGSupply that had stock and also had stock at reasonable prices.

Next on the list is carburettors !

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