PROJECT FIREBALL
1 The problem: this adapter is cracked and completely the wrong thread; it was screwed on a couple of turns and sealed with PTFE. So how do I make a better one...
2 As the tank stub is intended to take a pipe, it has a conical hole in the middle, so whatever screws on should have a matching cone to effect a proper seal.
3 Using a taper-thread-cutting tap for the stub side, I made an adapter that will seal onto the stub as it is tightened. V marks are fuel flow and show which way to fit it.
4 The twin-float Type 29 Amal carb looked very sorry for itself. Archie had warned that the floats sometime sticks, so I thought it was worth trying to find out why.
5 You use much more fuel to air when using ‘dope’. Twin floats act as a buffer, helping prevent fuel starvation during periods of snap acceleration.
6 This needle clip has broken free from the float – it will still stop the float lifting higher than it should but may cause problems by vibrating with the engine running.
7 With a clean-up it isn’t difficult to solder it back on. Don’t get the float itself too hot, though – the two halves and the tube for the needle are soldered together too.
8 The clip’s a bit loose on the other float; it’s a ‘cigar cutter’ clip that locates in a groove in the needle. By gently spreading it outward, you can increase its grip.
9 It’s worth cleaning the rest of the carb too; the sealing washer on the bottom nut has seen better days, but luckily I have spare gaskets ‘in stock’ for these carbs.
10 The pilot jets are drilled into the jet block; it’s worth ensuring all these are clear, although they’re usually OK unless they’ve corroded from long standing.
11 With the carb cleaned out, reassembled and refitted with new fuel hoses, it looked much better. Hopefully it will be more fuel-tight in future!
12 I made up a new HT lead to replace the melted one. To prevent seizure of the screw-in pickup (and seal the threads) I use a smear of petroleum jelly.
13 The contact breaker points were pitted, so I refaced them on an oilstone until they were smooth before reassembling and setting the gap.
14 The tensioning spring was missing from the points – lost in some long forgotten paddock. Probably doesn’t do much, but I fitted a spare I had.
15 The left footrest was wobbly and higher than the right. An eightsided hole in the rest fits a square shaft, moving round a notch would do it...
16 ... but the hole was distorted and it wouldn’t fit the next notch. Filing it square sorted that, levelling the footrest, but the brake rod was now too short!
17 I couldn’t move the brake arm round to match, but I was able to fit it the other way round, cranking it tidily inward instead of sticking out.
18 Wobbly footrest was bottoming on the square shaft before it was tight; to pack it I took a ½in washer and filed four corners into the hole to make a spacer.