POST 15: The Orange Bike- Fueltank

Moving onto the orange bike, its obviously a bit of  a task. The steering head was loose and either needed adjustment or new bearings. The headlamp is missing, the piston and barrel need replacing and although it turns over readily, the rear wheel is very stiff. All indicators are missing. I'm intending to strip it and renew motor and wheel bearings and seals, but maybe not the main bearings unless it proves to be necessary. There's a lot to sort out round the carb (which is different from the blue bike) and the fuel/oil tanks need de-rusting and a new petcock. The tank here also differs from that of the blue bike; oil and fuel tanks are joined and both situated behind the saddle. The space under the saddle on this bike is used for the battery and electrics rather than fuel.

I started with the tank and the fuel gauge. The tank is hidden by the rear orange fairing which needs to be removed to release the tank.

Undo the forward top fairing bolt

Front fairing bolt

... and the two dome nuts holding the rear faring to the chrome frame beneath.

Dome nuts removed

You have to undo the front bolts securing the chrome frame too so it can slide backwards and off the faring studs.

The front of the orange fairing is held by two large nuts holding the forked ends of the orange fairing- one side doubles as suspension mounting. You can then pull the chrome frame backwards and off the threaded studs at the rear of the fairing. The fairing itself slides backwards and angled up at the back to clear the large suspension studs. This detaches the orange fairing.

Orange fairing front fastening nuts

There is a collar bolt at the rear beneath the tank holding it to the chrome frame. Once this is out the tank and frame can be separated- the tank can be lifted up and slid  backwards to unclip it from the chrome frame. This assumes that the fuel pipe has been disconnected already but in my case it was missing anyway.

Bolt hole in base of tank for shoulder bolt

Shoulder bolt in rear of chrome frame.

And the shoulder bolt itself- rubber mounting through chrome frame.

I did need to detach the oil hose from the tank.

Oil hose detached from tank

Oil hose detached from tank

The tank was then separate and I could unfasten the fuel gauge- it unscrews like a fuel cap, but its very stiff and solidly fixed with a packing ring. Sadly the fuel gauge looks too far gone with rust.

Fuel gauge unit- note twisted central shaft which is rotated when the float rises.

The gauge here is upside down with the float stuck at the bottom. It should be free to rise up with the fuel level and rotate the twisted central strip. The top of this strip bears a plastic collar in which a magnet is embedded. The magnet interacts with the arm of the indicator such that when the shaft rotates the needle moves with it, but there is no physical connection between shaft and indicator needle. This presumably is to prevent escape of vapour(?).  

Fuel gauge gummed up with rust- needs cleaning and de-rusting. The float is seen here at the bottom of the gauge- corresponds to "empty" whilst at the other end of the twisted shaft the plastic collar containing the magnet is visible. All very corroded.

Its a simple system but even when I'd freed the twisted drive rod, the indicator failed to move. This means it will need to be dismantled further to free up the indicator needle on its pivot.

Fuel gauge- the scale indicator is retained by the chrome ring trim which is staked to the body of the gauge by 4 punch marks.

Gauge-indicator section

This gauge is probably too far gone but I'll try to repair it. There is a packing ring beneath, stuck to the base- that could be eased off.

Easing off the packing. Note the plastic boss which interacts magnetically with the needle indicator

Once the packing was off it was clear that the gauge was cinched together by a tapering crimp of the chromed securing ring and 4 indented punches. It took a long while but I was able to bend the taper outwards using a small pair of pliers, and finally tap the chrome ring down and off the central body and glass indicator. I supported the  gauge on its glass side upside down on a close fitting rubber bung whilst I tapped the chrome ring down. Note- here I should have used a jubilee clip around the chrome ring to keep it in shape as I teased the crimp outwards.

Tapping the chrome retaining bezel down so that the gauge body is released... I should have used a jubilee clip to protect the shape of the bezel.

Finally the chrome securing ring bezel tapped down and the working parts were separated. There is a close fitting rubber seal stuck firmly to the glass. This was difficult to remove because it extended downwards past the sides of the glass.

Rubber sealing ring stuck to the indicator glass.

There is a second seal beneath the indicator plate- this has a pocket shape and the edges of this rise up around the indicator plate and also hold the glass to protect its edges.- The side of this pocket could be seen at the edges surrounding the glass. 

Seal removed The edges of the lower pocket seal are visible at the sides of the glass

Upper seal as removed from glass.

Remove the glass and the indicator plate then detaches from the body of the gauge. It may be held by the lower seal. The spindle on which the hand pivots comes off with the the dial indicator part. The needle did not rotate on the spindle so I levered it off and cleaned it to restore motion. 

Looking inside the body of the gauge. The top of the plastic magnet collar is visible in the centre. The gauge section has been detached and lies upside down next to it with the rubber cup seal now exposed.

Spindle drive for indicator needle seen from the rear of the indicator scale.

I did my best to clean the rust off the frame and reassembled the gauge. I had to carefully tap the inner body down and then peen the edges over. Its by no means perfect but it should be ok.

The tank itself was cleaned by my usual method- basically shaking with a handful of M10 nuts to remove loose rust and gum,  followed by a 2-day soak in 10% citric acid to remove the rust.

I needed to order a new 14mm thread fuel tap since the old was missing. This came with a filter that was too high to fit into the tank spbI removed the old filter which was jammed in the tank (screw in  self-tapping screw and pull) to vlean in the donicator and fit onto the new tap.

I also ordered a new 3mm centre fuel cap in case I need to blank off the gauge but gor the time being I'm fitting the gauge.

Reassembly was slightly complicated since I had to include the number plate holder complete with rear light and the indicator bar missing when I got the bike. The indicators required fabticating a new mounting point and removal of damaged insulation that would otherwise have shorted to the frame. Its fairly straight forward so is not illustrated. The ballast resistor also needed installing and that was found faulty so it was repaired. See separate post.

On the end I hD to replace the flasher unit as well but finally wiring was installed and functioning.

I coukd then refit the fuel tank and its upper facia