Nah - I wouldn't lock-tite the pinch bolt. Would you should do though, which will also solve your problem, is to seal both ends of the pinch bolt assembly with RTV sealer. I use "Blue" RTV and it works fine. This prevents any air leaks through the bolt or threads of the pinch bolt, which can be a common area for leaks. Make sure you seal the carb body/crankcase join, and the back plate as well while you have the RTV sealer out