So I just got a 90 600 for cheap. Didnt really know much about it but its been sitting in a garage for years. on to trying to get this thing to fire. So far I have put in all new plugs, Changed the oil, cleaned and adjusted carbs (best I can according to the shop manual without it running.) new battery. Also new ignition switch. When It cranks I have spark on all 4 plugs. but It will not catch, most ive got so far is a light backfire and if I hold the choke it'll crank a little faster but not even really sputter. Kinda lost where to go to next? could the timing be that far off somehow, or valves that far out of adjustment? I havent dug that far into a street bike motor before, im used to working on small/big block V8s. Any help is much appriciated. Oh and does anyone know a good place to get parts for these other than fleabay, the cable on the idle adjustment snapped or something, the whole center of it is gone, so for now theres just a screw threaded in so I can adjust it.