Reply To: Upgraded regulator rectifier and stator
Sorry , I edited my reply to say this:
A bit too high 14.9 when idling – Should be 14.0-14.4v – but we can tolerate 14.5-14.6 as normal too.
Hyosung’s limit is 15V so you’re just on the border!
but OEM or Knockoff regulators are just wild = they would jump around from 11.5 to 16V! = 16V is basically time to blow up the battery or cook everything that’s attached to the harness that needs a 12v source.
Check yours again at 5,000 rpm (as per service manual) and tell us ?
I just seen your new reply now, i would check at 5k rpm and advise ?
Find out if voltage changes at the battery side when turning on the lights on/off , since these are 55 watts right out of the gate.
Since you have a brand new stator , the stator unit should be OK otherwise the bike wouldn’t start =A bike won’t start if its the wrong stator due to different pulse timing dots on the flywheel.
Also when the bike is running ===> disconnect the regulator , and disconnect only the “yellow” stator plug.
Measure at 5,000 rpm at the stator itself
Pin 1 – Pin 2 = Volts AC
Pin 1 – Pin 3 = Volts AC
Pin 3 – Pin 2 = Volt AC
This way we can check each yellow wire how much voltage in AC is being output at 5,000 rpm so we can fully rule out a new stator.
Then we progress further in to the harness itself if there is something on the harness or some kind of part attached to the harness that’s causing things to go haywire.
As long as the stator is feeding AC power in to the regulator itself ==> Disconnect the regulator from the harness and measure its 2PIN plug in DC , this should be between 14-15V DC , 13.5V DC would be Hyosung’s absolute acceptable lowest charging rate (less AC power when idling ofcourse)
Keep the yellow plug connected to the regulator , we’re just measuring the regulator’s 2Pin DC output once it takes the stators AC energy from the yellow wires.
I hope i made sense ? If not , let me know!
My bike loves to charge at 14.2V despite having the same kit as you , but it does the job, i would love to have 14.5V , but alas , its 14.2V all day , in any revs and has been that way for a few years now so i’ve yet to change the stator , it’s not bothering anyone. When i turn the lights OFF (removed the bulb!), then i see a big spike at 14.7V and stays there all day long.
So personally myself i have an achingly long job over the winter to strip the entire bike down to get to its harness and repair it and give it some nice TLC with ACF50 around its plugs , as to be fair some connectors near the front of the bike have oxidized a little bit (stupid wintry northern freezing wet climate! – I envy Australians)
Believe it or not , in July 2025 , i could not start the bike as the battery was 11V as soon as the key turned on (headlight is permanent ON for later models of the GT series bikes) , and i went under the bike , the headlight wires where burning my hands! – If i disconnect the bulb , she starts flawlessly , but connected them when running made the issue worse, i was flabber gasted – I tested the battery with a YUASA Load Meter (it does a deeper dive to verify battery is OK or not) , it was fine, mind you this was a YUASA battery which brand i trust the most and it was 3yrs old without fail , i swapped regulators again, same issue.
So in the end i replaced the bulb and got a new battery too. As the bulb was killing the battery other than the charging system. I wasted £120 all because of a bulb! – Mind you, this was 6 month old bulb too , so i made sure to get another one that isn’t “defective” / “bad batch” , excuse the quotes. I went back to my old regulator that’s always been good to me, and we are back to 14.2V (not a great number but ugh… old harness needs love eventually) and new battery , starts everytime now.
So i will make a routine to touch my headlight wires every now and then , and i also put a volt meter mod above the dashboard , that’s how i know the voltage is whenever i am with the bike. Great mod. Just tap in to your “side little bulb” inside your headlight and don’t cut the wires. Just copy the plug , make a “male – female” bridge
in the end [side light little bulb]–>female end–> (start of male mini bridge) with wires going to the volt meter–>female end of mini bridge) –> male end of the main bike harness. That way i can disconnect it at will and stays inside the headlight shell away from any water / nature attacks. Knowing Hyosung isnt making any harnesses for GT bikes (discontinued model) , best to preserve it.
I am digressing sorry , hope you had some ideas of checking for unusual power robbing along the harness too.