my rd125 sat at my dads for the last 20 yrs. I removed gastank, flushed several times. I removed the carbs.and cleaned all jets,probably 5 times.I replaced 1 coil.The bike starts great, revs pretty good in neutral.When I put it in gear it goes o.k. in 1 gear,and runs worse each gear.I can´t get past 3 gear or 25 m.p.h. I have new plugs, new gas, timing looks good,point gap good.HELP!!!