MF, I just drill the hole in the cap, run the 6 mm tap through it, then put a nut on the bolt and screw it in so the nut sits flat, then put a smear of JB weld around the nut. I tried a new method on the cam on the 24 I did a couple of days ago, this time I just removed the lump on the top of the cam so that it had a gentle slope, just sort of rounded it off. Seemed to work well, and I now run a wire up the inside of the snorkel and connect the wire to the stop I fit to prevent the lever being pulled back too far/hard and pulling the cable out of the cam which breaks the section the ball fits into. All this modification does take time but it at least makes the carby work well without the dramas of the original kill switch design failure