Motorcycle Repair: 1979 CB750K Issues., 1979 honda cb750k, charging system

Question
I actually have two issues with my 1979 Honda CB750K LTD.  The first issue is that I've been combating a difficult to diagnose charging system.  At this point I've replaced the stator but even at 2500 RPM I'm sitting just below 13.5 V.  I am assuming that the issue remains in the rotor, however, on this bike is there anyway to test the rotor without removing it?

My second question is in regards to a very, very pesky issue getting the bike to even run with the choke off.  I can get the bike to idle at or around 1500 rpm just fine with the choke on.  At any point that I turn off the choke it dies.  The only exception to this is when I'm going highway speeds and I can then fully turn off the choke, but the second the throttle isn't fully engaged if I don't turn the choke back on it will die.

Regarding this last issue, a bit of history.  I've cleaned the carbs (likely will need to do it 10 more times, or pay someone to do it), replaced the air filter, spark plugs, ignition coils (they were cracked in half), and have also synchronized the carbs.

Any help would be greatly appreciated.

Answer
Hi Andrew,

"At this point I've replaced the stator but even at 2500 RPM I'm sitting just below 13.5 V." This alone tells me there is NO issue. Believe it or not, no matter what you replace, the system may not charge any more than that. From my experience, anything above 12VDC Is good, what youre seeing is just the rate that the charging system re-charges the battery. If you have a fully charged battery, it only uses what it needs to recharge it. If your battery was marginal, it will charge at a greater rate (which is possibly what youre used to seeing)

The 1st thing you should check is take a can of carb cleaner, very lightly push on the button to dispense it pointing at the carb boot where the carb boot meets the engine. If the idle goes UP or the engine DIES, this is where the culprate lies! Sounds to me like you are getting an improper amount of fuel. Easily overlooked and easy to fix.
Given the carbs have just been cleaned several times (jets removed and light visible through them) This points to that issue.
New boots are NOT all that expensive, and since youre now a pro at removing carbs, this'll be a snap! Thanks for such a thourogh explanation! makes helping that much easier...

Hope this helps!

~Mark Panka