My VF1000 when accelerating in top gear from around 70mph starts to slightly misfire, or stutter, almost like a cylinder is cutting in and out.
I’ve checked the plugs and electrics (not the coils, yet) and cant find a problem. I thought maybe there was a problem with the fuel pump but, again, it seems ok.
Any ideas ? Could this be due to a perforated diaphram in a carb?
It’s the carbs… Might be a diaphragm , but it’s more likely to be muck and lacquer deposits from the fuel… These carbs do not work well when dirty… I’ve had mine apart 3 times for the same problem as you describe. I found 2 diaphragms with pinholes - replaced… The float heights were WAY out - reset to 7.5mm… Finally fixed the problem by stripping completely and thoroughly cleaning every orifice with carb cleaner and compressed air. Rebuilt carbs with Keyster rebuild kits (NRP Carbs, Manchester - 0161 832 8646, Ask for Andy, say that Jeff Mitchell sent you and he may well treat you kindly…)
Also - for confirmation of the fault try searching through the USA Sab/Mag/Interceptor Forum - you’ll find so many hits on carbs that you’ll wish you hadn’t looked…!!