The solenoid has absolutely nothing to do with the spark. You could be looking at a bad coil ( the one of your recon may not work on the this quad), bad coil wire/plug boot, bad plug, bad stator, sheared flywheel key. If the 300ex CDI works, then you will know that you need a new CDI, otherwise, I would check the list of manuals that Rocky Mtn Honda has posted in the Honda forum and see if your model is listed in there. There are some tests that you can do on the electrical components so you can find the faulty part or at least rule some things out. BTW, I am moving this thread to the Honda forum, for some reason it is in the Yamaha forum now.
Yours truly, sincerelly, love always, Josh aka The DirtDemon.