My bike is a 125t1 (1977) and I have been refurbing the carbs (PD26). Everything is ok except the slow jet fitting beside the main jet fitting. The old one apperared to be press fitted in the body of the carbs but hte new one is supposed to be screwed in in the normal way. I have just left the old one on (both carbs). Anyone with similar experience? How iimportant is the slow jet?