Nsu Quick 50 restoration : Fuel tank and tap

Fuel tank is sound but badly affected by surface rust and associated pitting- the tap looks to be in poor condition.

Tank badges are held with 3 M3 screws each- 3mm countersunk. These were stiff and one was broken on removal- I will renew them all.

The centre alloy trim strip is simply clipped through the eye at the rear of the tank and under it at the front. I straightened and removed the trim strip.

Alloy trim at rear

Alloy trim at front

Tank with trim removed

The strip itself has a chequered flag design- I don't know if it was original but its delaminating and in poor condition so I removed it.

The trim strip sits in a rubber channel which I removed and cleaned for reuse.

I will try to polish the trim strip as it does cover the join in the tank but the metal is pitted and I'm not sure how much I can rub it down without weakening it. I'm also thinking that even though the chequered tape is not original, it does represent something of the history of this bike so I feel justified in reinstating it.

I rubbed down and skimmed the tank with P100 before rubbing it again to fill the pits. Finally resprayed in primer- white and masked up for the grey.

The Fuel tap

The tap itself is a complex design- Note that the intake for the bulk tank fuel (long pipe) is unfiltered as it leaves the tank- there is a second filter integral to the tap at its base which filters it before it enters the carb. The reserve tank fuel (from the lower part of the tank) is presumably more likely to be contaminated, so is filtered as it leaves the tank by the small conical filter seen in the picture, and again by the integral tap filter below. Reserve fuel is thus double filtered. The tap screws onto the tank in a clockwise direction but the union nut has 2 threads and also connects to the tap body in an anticlockwise direction.

Fuel tap- note longer main fuel inlet pipe and conical filter covering reserve inlet pipe

The lower union nut (tap to fuel hose) unscrews anticlockwise and also releases the fuel exit spigot and its filter. Looking inside the tap revealed both tap and filter clogged with powdery debris and residue. The filter was stuck onto the exit spigot

The exit spigot pulled out of the lower union nut, I detached the remains of the hose and its ferrule. At this stage the lower filter remained attached to the spigot.

Components of the lower spigot- filter attached broken pipe and ferrule.

The upper union nut unscrews anticlockwise as normal and comes away with the top filter.

Tap as disassembled

I blasted everything through with carb cleaner and then cleaned in the sonicating bath.

Both filters were torn and both showed deterioration of their sealing washers so I carefully freed them from the remnants. In fact both filters are shaped like hats- the upper filter is like a witches hat and the lower more like a bowler. Both have a sealing washer bonded to the upper surface of the "brim" and new filters seem to come with this. However in my case these parts had deteriorated badly and had to be picked off carefully although that foes allow me to fix the tears in the gauze.

Upper filter "witches hat"- sealing washer eased upwards

I was able to trim them to remove the torn sections and then flare the gauze out to create a new "brim". This I sandwiched between two fibre sealing washers in each case.