Hi guys I'm doing s project myself which is basicly a Golf mk3 which I have restored all the body work, I've rebuilt the head and done all the belts. Unfortunately the single point injection system is failing in various ways so I'm going down the route of bike carbs so I bought some YZF 600 thundercat carbs off a friend of my father who owns a motorcycle shop and had them for 40 quid, I've got the materials to build a manifold for the carbs to go on, I'm just scratching my head over two things there's 3 pipes going into the carb, one is water for heating them in cold times and one is fuel intake I don't know what the third is any ideas? Thanks