the bike turns over like it normally would, it just doesn't actually start.
so it turns and turns and turns and doesn't start

 

If your batteries are good and the starting system is fine then it could be an ignition problem or a fuel problem. I've been told before you test for any ignition problem you should always do a compression and leak down test first. Just to clarify if its electrical or mechanical.

If you don't have the tools or the know how to do any of that I recommend taking the bike into a shop and having the problem diagnosed. It'll save allot heart ache. And if you're one to replace parts under assumption it'll save you money too. (To at least have a diagnoses done.) Shops usually charge an hour of labor for a diagnoses and no more than that. So maybe around 80 or 90 bucks.

Keep in mind they are only going to diagnose what you specify so make sure you're very detailed in your explanation of the problem.

Some tools that you would need are a; compression tester, leak down tester, (To verify if its a mechanical or electrical problem. Also requires an air compressor.) peak voltage adapter (At least) and that is for your ignition system. Something a shop has that you do not and is a bit pricey is an "ignition mate" If you have those four tools then you would be able to pinpoint your problem considering it is related to an ignition/mechanical problem.

If those tests all passed with flying colors then it would be good to examine your carbs and make sure they are clean, the float bowl level's are correct, the jets are clean. (Mainly the slow/pilot/idle jet, used for starting the bike unless the choke is on.)

Its a process that takes a while for someone without the tools and/or know to perform the tests. So unless you would like to invest in those tools which would be ALLOT more than any diagnoses test. And unless you're a mechanic and plan on using the tools often it would be a waste of money. You should take it into a shop and just save yourself the money and time to find out the problem.

Edit: I'm sorry one more things is, if you know you still have a charging system issue make sure all your charging system issues are resolved before diagnosing any other *possible* issues. Focusing on one problem at a time makes things easier IMO. And I'm sorry if I seem confusing...