1972 Suzuki GT750 Gauge Shells – Update

After six long years, I am finally down to my last twenty sets of GT750J reproduction gauge shells and about fifty reproduction speedometer reset knobs. It has been a journey, but I have no regrets.

Recall that I started this project in 2012 when I picked up my first Suzuki 1972 J model and started taking a look at what options were available to repair the cracked plastic housings on the gauges. Suzuki only used these plastic shells for the 1971 Japanese Domestic Market and 1972 General Export model years, and they are often broken. Repairs are possible if the crack has not extended up into the clear plastic lens, but if the lens is also cracked then you have a real problem.  The idea of having the gauge shell reproduced came about following discussions with my friend Allan Tucker from Barbados. We looked at a few different reproduction options, none of which proved viable. I then started the process of reverse engineering the original design and had some duplicates created using 3D printing which at the time was useful as a ‘proof of concept’ but useless as a finished product. The issue was the clear plastic lens. The 3D printing materials and processes available at the time could not produce a clear plastic lens with the right optical characteristics suitable for a restoration. I suspect the same is still true today. While the test blanks were of no use as replacements, they did confirm the design and provided me with a sample that I could then show to injection moulding companies.

In the end, I went ahead by myself to finance and organise the manufacture of the shells, and as I first documented (at this link) a company in Edmonton worked with me to create what I think is an excellent product.

When I first looked at having these shells reproduced I tried to guess how large a market there was. The original GT750 production numbers would indicate that about 20,000 of this model were originally sold worldwide. Hagerty Insurance in the US published an interesting chart giving survival rates of motorcycles by manufacturer which showed that about 45% of all Suzuki’s were still in use after 25 years. Extrapolate this out to 46 years and the number of survivors starts to look quite small – certainly less than 10%, so for 1972 model year GT750’s specifically perhaps as many as 2000 machines. While the numbers for a specific model like the GT750 will differ from a those of a Suzuki moped, I note that the sole GT750 registry I know of, which is maintained by Martin K. in Germany, only shows about 420 GT750 J’s in total. If you then consider that not every gauge shell is cracked, and that some people are happy to use later model gauges rather than the originals, then it becomes clear that the total available market for this product is quite small indeed. I do still own the injection dies, and now that the cost of creating the dies has finally been recovered, a second production run of tachometer and speedometer shells would be much less costly to produce. At the moment though, I am not planning on having more of these shells made as I suspect the available market is near saturation. At the rate of current sales, what stock I have left should last about one more year (so mid to end of 2019) and then perhaps I will re-evaluate my decision.

And of course there is still the problem of the temperature gauge shell as I only had the tachometer and speedometer shells copied. I didn’t do it initially as the temperature gauges are often not damaged, and as well due to the manufacturing costs of the injection die they would have to sell for about the same cost as the larger tachometer and speedometer shells do currently. Cost is definitely an issue for some owners, but it would be a nice addition for restorers. Possibly a future project for someone else perhaps !

For the three 1972 GT750’s of my own, I now have fully refurbished gauge sets so the original problem that started me down this road six years ago has been addressed. And roughly 180 other GT750 J owners’ world wide have also benefited, so I’d call that a success !

😎

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2 Responses to 1972 Suzuki GT750 Gauge Shells – Update

  1. Anthony Greenwood says:

    Hi, could you tell me how much for a pair of shells and a reset knob please?
    Kind regards
    Tony.
    (U.K.)

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