Continuing on with the GT750 restoration, the design has been finalised, and the frame has been in and then out of the The Welding Shop here in Calgary – the tank had to be steamed out before welding, but that wasn’t too hard to arrange as there was a radiator repair shop next door to the welding shop and they were able to do this easily. I either created new mounting tabs based on the GS750E measurements, or adapted/modified GS750E mounts to be fitted to the GT750 frame. Cactus Machine has finished the work on the new brake lever and everything actually looks pretty good !
The frame with the tank extension and the mounting tabs was sandblasted (you can read about that here) and I have finished off the shaping, filling and priming of the tank so it is now ready for the next couple of steps – these being sealing, and then finish coat painting. As well, I have double checked the location of the mounting tabs for the seat hinges and rear deck and needed to make a couple of minor ‘fitting’ changes. I wasn’t happy with how the GS750 seat sat on the GT750 frame – it was a bit too high – so I modified the rubber bushes that fit into the underside of the seat and which rest on the frame members. This has let me drop the seat about 3/8th of an inch, and overall I think it looks better as a result. I also decided to raise the rear deck slightly at the rear which meant I needed to relocate the mounting tabs from where I had originally planned, by welding new ones in place.
The final result is as below – In the left photo, you can see how I’ve stretched out the GT750 tank, as compared to the stock shape (the black tank) along side it. In the middle photo you can see how things line up when mounted – the rear deck is off a 1978 GS750E, the seat likewise and the tank is from a 1976 GT750 which has been modified as described. To the right is a photo of the tank lining kit I plan to use this week to seal the inside of the tank and ensure everything is leak proof and (hopefully) will stay rust free.
There are many products on the market for sealing gas tanks – and these days it is complicated somewhat by the introduction of methanol into gasolines making fuel more corrosive. Some tank lining products, used for example in aircraft tanks and which have been used in some cases for motorcycles will work fine on pure gasoline/petrol fuels, but these linings will actually dissolve if exposed for a prolonged period to newer bio-fuel mixes. There is some very good information here , and as well more information here and here. After reading what I could find, I went with the Caswell product (the American link is here for those folks from outside of Canada) and we’ll see how it goes.
Once the tank is sealed, I will be able to proceed with the finish paint work on the tank, side covers, and rear deck – but before that I need to refurbish the controls, gauges, headlight etc., etc. – so there is no lack of things to do !
The ‘home’ site for the GT750 rebuild project is here.