Forums 🚥 PIT STOP 🔧 Hyosung Technical Help [Tutorial] How to swap Carb Main Jets – Hyosung GV & GT 125/250 Reply To: [Tutorial] How to swap Carb Main Jets – Hyosung GV & GT 125/250
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Hi Guys I’m looking to upgrade my main jets and do a carb rebuild at the same time. My GV125 had been stood around for sometime before i bought it, in saying that i got lucky getting it going but i know it needs attention very soon. I’m looking for the correct jet size and a rebuild kit for the carb’s. As well as this I’m after some tutorial on how best to remove the carb’s as it was a nightmare the last time i done this and don’t want to struggle unnecessarily. Its fitted with straight through ss exhaust also, thanks in advance Shane
If your local dealer doesn’t have genuine Mikuni jets / EBC ones , you may send me a message as I for sure keep a stock of older genuine (on ebay) & some new jets.
I usually send jets with air filters on some custom orders.
I have dealt with the GV bikes a few times, one thing is for sure:
– Pilot Jets do not need upgrading at all.
– Stock main jets are identical (87.5 front / 87.5 rear)
So a good upgrade commonly is the “90 Main Jet (Front)” and “92.5” (Rear)
Ofcourse the rear is bigger as its the hottest engine, so a bit extra fuel at the back has a cooling effect & slight torque boost in 5th gear.
If you head to Halfords or EuroCarParts – My fav cleaner for carbs is WYNNS FUEL SYSTEM CLEANER – It’s a green can , ofcourse any good carb cleaner will blast every hole clean.
Also , i must stress a little here – The “STARTER JET” (which can’t be removed) has a very very tiny hole , ensure you have a good carb cleaner.
After the STARTER JET (that big metal tube that you can’t remove) is cleaned up, your bike will start a LOT faster.
Starting / Cranking = Starter JET
Slow Ride / Idle = Pilot Jet/Main Jet
Normal / fast Riding = Main jet.
1 more thing. Head over to poundland & get 3 cans of AIR DUSTER – When the jets are dry , use the air duster to blow the holes clean.
Use the air duster to blow everything inside the carb, after it has dried up from a carb cleaner liquid.
A full clean will really do wonders to the bike. Good luck!
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