ST1100 Fuel Tank Mods

For the ST1100 redesign, having decided to butcher the fuel tank to make room for the battery, the spare tank I’d bought in a job-lot came into its own.

ST1100 P4 F04 Fuel

As it had been left open for a year or two there was no fuel vapour inside so I took an angle grinder to it.

ST1100 P4 F06 Fuel

What luxury, to be able to get an electric drill with wire brush inside the tank! I also treated it with rust killer to be on the safe side. Rapid Metals of Coventry were very helpful in supplying small quantities of steel – some 1.5mm plate to cover the hole in the top of the tank and some 3” tube for a filler spout. The original filler cap and bayonet fitting would go on top of the tube. I did the cutting out and local bike mechanic Jason of JM Motorcycles (sadly no-longer in business) did the TIG welding.

ST1100 P4 F08 Fuel

The two bolts are for a seat bracket yet to be designed at this stage. The fuel pump goes in the hole at the back – the one from the spare tank didn’t work so I transferred the good one from the original tank, with a new sealing gasket. A couple of coats of black Hammerite finished off the tank. One bonus is that it can now be tilted forward to remove it without taking off the air filter.

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