andy2175m4

XT 600 with dual carb, one side is slide carb, other side is CV carb, single cyliner with 2 intake ports. , the bike wont start so I rebuilt carb still wont start, removed the cv carb and blocked port, on just the slide carb bike started right up but put CV carb back on and wont start, all seems well but just wont start, any ideas ?