ANOTHER KAPUT COIL
After reading Bill Roberts’ letter in RC194, I thought I would add my ha’porth. Nearly ten years ago I bought a poorly BSA A65 Thunderbolt. It did not run well. After doing the basics to improve it, I tried to adjust the points, but I undid the wrong screw on one set of points, which upset the timing on one cylinder. After trying unsuccessfully to retime the one cylinder, I gave up and fitted a Pazon electronic ignition system – problem solved, nice.
A while later the engine started to misfire and generally mess about once warmed up, if travelling in slow moving traffic. The carburettor was well worn, so I fitted a new Amal Concentric. This transformed it and it was lovely to ride. Until last year, when on a club ride it developed a misfire and hesitation after 22 miles if I gave it any more than a light throttle opening. After checking everything and finding nothing wrong, I thought how odd it was that this happened after exactly 22 miles every time.
So I changed both coils; I had some spare ones in the shed. It was instantly back to normal. They’re still on it and it’s going great. I had not left the ignition switched on for any length of time without the engine running. Normally the coils do not give too much trouble but changing them proved them to be at fault.
All strength to the best old bike magazine. Dick Turner, member 5240
Proof once again that every carb problem can be solved by fixing the electrics. Or vice versa. Or neither…