How to change / upgrade fuel lines & fuel filter on CARBY GV125 & GV250 Diagram
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⛽ Fuel Line & Fuel Filter Upgrade – CARBY GV125 & GV250
Note: This is for carburetor models only – NOT for EFi/Injected bikes. This tutorial was created while servicing a customer bike, so pictures are rough, but follow the steps carefully.
Sometimes you want to upgrade fuel lines (like these we sell) or overhaul the fuel system with fresh parts.
Step 1 – Preparation
- Get your new fuel lines, fuel filter, and hose clamps to avoid leaks.
- Switch off the fuel tap under the tank.
- Remove old fuel lines from the filter, pump, and carb.
Step 2 – Fuel Pump Connection
Locate your fuel pump next to the battery. Follow the arrow marked “↘” (downward). Attach your new fuel line there and clamp it firmly.
Route the line under the middle frame plate (starter relay area) and bring it out from underneath as shown:
⚠ Pause here. Do not continue until you are ready. Keep lines organized to avoid mistakes.
Step 3 – Carburetor Connection
Connect a full line from the fuel pump “UP ↖” arrow to the carb location. Clamp securely as shown below:
Step 4 – Reconnect Fuel Tank
- Place the fuel tank on the bike and connect the fuel level sensor.
- Connect fuel tank → fuel filter → fuel hose from pump (DOWN ARROW ↘) as previously indicated.
Step 5 – Final Checks
Check all connections before starting the bike, and verify again after a test ride to ensure everything looks good.
⚡ Bonus Tips
– Use strong braided lines if replicating our “S” shape from pump to filter; standard hoses may kink and starve fuel.
– Ensure the fuel filter is installed in the correct orientation.
– Use quality braided hoses only – cheap lines reduce performance and reliability.
– Use E5 fuel only. E10 is not suitable for carb models. UK GOV recommends E5 for older carb motorcycles.
Check official guidelines here.
– If anyone suggests E10 on a carb model, ignore them. Clueless advice can ruin your bike. ❤Did I cover everything? If you notice missing steps or have improvements, please comment below!
Ride safe!
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Hi you may be able to help me I have a hyosung gv125 aquila 2009 carb I found the petrol pump on the left side of the bike near the battery but there seems to be a petrol pump on right side near the front air filter I don’t know if it is fuel pump or not could you help
Thanks
JOHN.
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Hi you may be able to help me I have a hyosung gv125 aquila 2009 carb I found the petrol pump on the left side of the bike near the battery but there seems to be a petrol pump on right side near the front air filter I don’t know if it is fuel pump or not could you help Thanks JOHN.
Can you post a picture of it please? I think i mentioned this on your own topic.
In any case we have to see whats going on with the bike & what the last owners were trying to do.
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Hi I have a hyosung gv125 aquila 2009
I have put a new vgc pump and vacuum petrol pump on my bike I followed the directions on the site but it still won’t pull petrol through to the carb can you give me any ideas why it won’t work iam at almost to why it’s not working any help would be very grateful
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Is it possible to do a compression test ?
You will need to remove both spark plugs out, crank bike at full throttle for 5-10 secs max, then report back with some figures you got.
If we can start there first, it makes it very easier to diagnose fueling issues if we get the engine out of the way first (since it is the engine that needs to compress well to lift the fuel out in to the carbs)
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Hyosung gv125 aquila 2009 Hi sorry it took so long to get back to you but my compression tester has just come
And the compression is -front 10bar (145 psi) and rear 10bar (145 psi) so I that is good so the problem is why it’s not pulling the petrol through to the carbs is there any thing else you can advise with this problem thank
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Yes when the bike cranks up (throttle closed) , you will see it go inside the fuel filter if its a clear fuel filter (not the cloudy ones that are hard to see)
Then , make sure the “pump” next to the battery tray is connected the right way as per tutorial on this thread.
When cranking the bike, see if the “hose” going to the carb shoots fuel out in to a bucket next, let us know how it comes out.
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Is it sparking now? Both plugs ?
If yes => Go halfords and grab BRADEX EASY START YELLOW CAN
Spray the air filter (not the airbox), the air filter itself , until it is slightly wet and has a strong smell of it, be outside(!!!!)
Full Choke on => Crank the bike with the throttle 5% open (not full throttle), as you want only a little bit of throttle open
As soon as it screams , open full throttle and hold it there , until you are confident to drop the revs (let go of throttle slowly), so it runs on choke for 5mins to burn off the easy start and pump fuel in to the carbs.
Let us know if that work?
Otherwise, let us know if pops bangs , or freezes up, then spins, freezes up and spins ? (like its trying to catch something)
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Not a problem John , keep us posted , hopefully we get somewhere at last!
Start a new topic on the homepage of this site, so that it becomes your own thread and we can follow it properly posting your results , pictures or anything to us to dive deeper.
Regards
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Hi again I have just checked the fuel pump again and when you turn it over the petrol is barely coming thru but if I put a bit of petrol in the carborator thu where the air filter is it starts up straight away so iam not sure what is going on even if I feed the carb directly bypassing the pump it still won’t start iam starting to wonder if it’s the carborator but the fuel bowl seem full so iam stamped
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I have went back to basics the fuel coming thru the pump is just dribbling thru and there is no fuel In the carborator bowls so have took the carb off to look at the needle valve and see if it’s not jammed or if the floats are working properly and I will let you know how it goes speak to you soon
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Use the link below to make a new topic as it will be easier this now. It might be beyond fueling issues etc, so making an individual topic specific to your bike could be easier for everyone to follow / reply to. Again, if its not fueling , then it will be something else deeper in the engine 👍
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Hyosung gv125 aquila 2009 carborator problems hi could you send me a diagram of all pipes that connect the carborator to the vacuum system I think the pipes are wrong some how from the vga to the carb manifold and there is a pipe from the petrol tank on the right hand side which goes nowhere I have checked the manual but it doesn’t show where all the go so if you could help it would be very appreciated
Many thank john
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Then add pictures so we see what’s going on. (Vacuum tutorial is already on the forum too GT & GV are the same , except GV has a manual tap that’s all)
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