motersicklebum

i obtained a free 82, 550 YICS, Maxim. i got it running after cleaning the carbs. it tachs up great in neutral but breaks-up while riding at about 5K rpm. it's doing the same thing that an XS 650 did to me. that turned out to be an ignition problem caused by a points retrofit..... the carbs on this 550 are probably not perfectly adjusted but they should't cause such a dramatic breaking-up at high rpm. to keep it idling i have to turn in the idle screw way too much which causes the rpm's to fall very slowly after i let up on the throttle. again, this is the exact same thing that my xs650 did to me.... so now i'm leaning toward a bad coil. any suggestions? where can i download a PDF repair manual for this bike? thanks, motersicklebum tim