yamaha dtr 125

hi.

can any1 help me please ive got a 1990 yamaha dtr 125 and ive got no spark after changeing engines (the old 1 had seen better days) the engine thats now in it is from the newer version of the dtr and thats the dtr x its got the newer stator windings in but still no spark but its still got the old cdi unit on the bike n im not sure if thats working or not ive got a newer cdi unit to put on the bike but aint got round 2 doing that yet n dunno if that'll cure my problem. also does anyone know where i can get carb kits from ie jets needles floats and that sorta thing. thank you