yes the keihin carb is very easy to work on. which does suck petrol from the tank. which causes a vacume from the inlet manifold to the carbs. if this is not working propperly try cleaning out the fuel tap. which has a filter inside. my bike is same layout as yours. a 1990 en 500. my triumph also uses keihin carbs the same system with no troubles.if you need more help email me direct