Reply To: Electrical problem with my Hyosung GT125R

[Ucvmn]

♠️ M77 wrote:

Sounds like weak battery if it can’t handle lights being ON and trying to crank it at the same time. I would recommend a fresh battery from halfords or SportsBikeShop website (trusted) , to get YUASA YTX 14BS , little batteries degrade faster and will soon mean new starter motor and relay , engine is happy when battery has around 200CCA capacity to crank considering its a thirsty 2 piston vtwin. Then confirm yourself or replace regulator or stator unit , if the following fails (even korea says change it too in their manuals) – Idle Voltage = 14V DC (max 15v/14.8) —> Lowest accepted 13.6V – 5,000 rpm voltage = 14v-15v (If it is 13.xx above 3,000 rpm, replace regulator, it will burn)

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Try with or without lights

https://streamable.com/59yez1

 

Try with jumper cable.

https://streamable.com/5oup1i

 

I guess it’s a battery issue.

But I forgot to use the multimeter to test the regulator.