1982 GW won´t start. Carbs were cleaned two years ago. Only rode the bike 3-4 times last year. Here´s what I have done so far. Plugs are good, drained fuel and added fresh gas. Pulled fuel line and fuel pump is pumping. Engine turns easily, just won´t fire. Have not checked plug wires for spark just yet. Need to know where fuel filter is loacted. Any ideas?