Original choke is a long cable (red arrow) running up to a bulky pull button that moves the choke bar outwards 15mm (blue arrow)...
The essence of a traditional chopper is simplicity. This junk needs to go. The following plan shows the simplest choke set up we can have. Unfortunately the choke bar connecting the four carbies is heavily sprung, so we can't just have a pull push set up but need to hold the choke out against this spring pressure when cold starting. We will pull the bar out with a piece of 6mm stainless round bar with a simple knob on the end. A couple of roll pins will give us full and half choke. They will be retained by a slotted nut attached to the outer carby top...
A piece of 20x3 angle is the starting point. You can see the texta marks showing the centre of the screw hole...
A piece of 3mm is welded to the open end for attaching the nut. Sorry about the blur, but I wanted to illustrate a method of welding on small pieces... don't cut the whole piece to shape, but leave some length to hold onto while tacking...
...then trim it to shape...
6mm stainless round bar and an alloy knob off a computer case. Fne male thread is trimmed off in the lathe and a 6mm hole drilled down the centre while still in the lathe...
Knob is drilled on the side at 4mm and an M5 thread tapped in. Thread is started with a taper tap and finished with a bottoming tap. You can also see a small flat on the round bar that the grub screw will bed into preventing the knob ever coming off...
End of round bar is threaded with a thread die set up on the lathe to keep it square to the shaft. Blue arrow shows thread. The die holder is retained on the lathe tool holder and the chuck is turned until we have a couple of threads. Then removed and threading finished in the vice in the normal manner...
Required clevis gap is measured...
Clevis cut in some 12mm square stainless with a 1mm blade...
Clevis is drilled for an M5 Socket Head Cap Screw. First drilled with a 4mm bit and then one wide with 5mm bit. Thread tap enters through the 5mm hole to help keep it square...
Something to practice is cutting off small pieces without them dropping; cut until the piece starts to push away...
Our new lever almost complete. The thread on the end allows the shaft to pivot (only half a turn needed)...
An M6 nut is drilled out to 6.5mm and the nut welded to the carby bracket...
A bit of measuring earlier demonstrated we needed to set up the bracket on the outside of the carby top not the inside..
Shaft and bracket installed and works. The shaft is blacked with Texta and marked for the roll pins...
... and then removed and a flat ground on the shaft so we can easily drill the two holes. Roll pins are nominally 3mm, but actually 3.2mm in diameter so they will hold in a 3mm hole...
Nut is now slotted 4mm with a 1mm disc...
Renistalled and at rest. Blue arrow shows roll pin...
Choke fully on. I'll drill a second hole for half choke. But for now it works perfectly. Quite a few steps to produce a simple choke, but the end result is simplicity and function... just what the super cool chopper jock needs...
