ON THE BUTTON
Talking to my mate Pete Scopes of Britsteel Classics in Dover, it seems we share a problem. Pete noticed that the Amal Concentric carb on his 500cc Triumph Special takes ages to ‘tickle’ – and I have the same issue with the front carb on my Norvin. It takes nearly a minute of fierce jabbing at the button before fuel will overflow – and although the rear floods easily, the front is the dominant cylinder and the bike won’t start unless both are flooded. Pete wondered whether the tickler button wasn’t moving the float down enough to open the needle valve fully, and decided to have a look in his carb box. He came back to say he’d found that, fully depressed, the ticklers stuck out anywhere from 5mm to 2.5mm from the gasket face. Thing is, the groove in the needle to attach the float is necessarily wide and the float can move up and down quite a bit without lifting the needle, so it is possible that a ‘short’ tickler just pushes the float down without raising the needle off its seat.
Checking the Norvin carb, I found the ticker was at 3mm. •sing two pairs of good pliers, I was able to wriggle the tickler shaft out (it’s just a roll pin, pressed into the button) a couple of millimetres and now it floods fine. Thanks Pete!
The only thing is, I couldn’t finish the day with a test ride, because while the bike was on the bench I thought I’d replace a blowing exhaust gasket and encountered a slightly greater problem that I’ll tell you about another time. Nothing’s ever simple, is it?!