I have 87 banshee . I just rebuilt everything frame j arm to a arm newer rear axle carrier.I owned the quad for 13 years ,and had a lot of fun riping up my town. i took it apart about 3 years ago because of blown crank seal. I bought gasket kit, seal kit,had crank welded and trude. I had head milled .015(15 thousands), a new top end boyesen rad valve, boost bottle 3/8 reed spacer, new intake boots, K & N air filter in box w/ cover off. TORS eliminator kit stock carbs w/ 280 main jet toomy exhaust stock electrical system. starts right up idles but breaks up at full throttle and boggs threw mid range but if you ride it for a while it will start runing good but if shut it off and restart it it will bogg and break up again.i have changed main jet from 270-330 but i think it runs best at 280. i checked spark and i have spark but i am not sure if strong as it should be . i have a xr 70r and it get a brighter spark then the banshee. dose anybody have any ideas what it could be? my stator dose not look very pretty but it tested ok .cdi? carbs? flywheel magnet weak maybe? can anybody help so i get back out in the woods and show all the newer quad riders out there who the king of the hill is !!! help banshee riders of the world !!!! :ermm: