Topic Tag


Fuel System Problems and Question about GV250

Hi all,

My girlfriend just picked up a 2007 GV250. We knew when we bought the bike that there was an issue where when you twist the throttle, it dies. It was too good of a deal to pass up on, so we decided to give it a try as her first bike.

When we got it home and started working on it, I figured it would be a fuelling issue, so we took the tank off, and there only appears to be one carburetor. Everything I saw online for these bikes showed that there should be 2 carbs, so I’m wondering if that was a factory thing on some of those bikes, or if someone has swapped this in since. If anyone happens to have any diagrams showing a single carb, that would be much appreciated.

The issue with it running does appear to be fuel related, as I did get it revving slightly by playing with the throttle adjustment on the carb, but it still does sometimes die, and when I do get it running sometimes it won’t idle now. Also when it is sitting not running, there is sometimes fuel leaking out of the intake side of the carburetor.

If anyone has any advice on what to try to make this work properly, I would really appreciate it.

Thank you in advance!


Carburetor GV 125 Year 2012

Hi Guys,

My Name is Max and I´m proud ower of a GV 125 classic KM4MF53A.

I need information about the settings of the carb. Especially the adjustment of the height of the float chamber.

I have adjustet it to 17mm because I only have the service manuel from the previous model. I Can tell you that it didnt worked well.

The slider with menbrane YK8844 is a little sluggish, means it doesn´t slide very well up and down and sometimes it is a little stuck. Any tipps?

Also it would be interesting which lengh the spring of the above mentioned slider should have.

Also I have difficulty loosening some screws, do you have any tips?

Maybe it is even easier to replace the whole carb, are there any opportunities to pay less than 630 Euro?

The matching workshop manual would be a blessing.


Thanks and sorry for the bunch of questions 😆

regards Max from Germany


Finding the right needle & seat float valve for GT25R

Hi and Hello, how are you doin?

Here is my story… I got all the good bits from the shop recently, some main jets of the correct size (for some reason I had 95 front and 100 rear jets), mixture screws etc but I totally forget to get the full rebuild kit witch has the Float Needle Assembly.  I need that pretty badly it seems.

The old ones were very embedded and had been mangled somewhat by previous attempt to remove them. I managed to get replacement o-rings on there and new needles (they also may be a problem). Bike started well and ran much better than before until I left it after the ride. I returned to find fuel leaking out of the front carb at a large rate, as well as the front cylinder intake full of fuel.  Not happy Jan! I should have expected that with the condition of the seat I put in there.

So anyone way, I plan on ordering the Carb Rebuild kit but it won’t get here (Australia) until after NYE. I have found a local Mikuni Distributor that has a large number or parts but I am not 100% certain what Mikuni is in the GT250R 2006. I found I another forum that said it is the Mikuni BDS26 Double but not able to confirm.

What I am hoping to find is the dimensions of the seat in the above kit and it matches the specs of this N133.200 Mikuni I can get locally. I want to double check the ones in the bike are the correct ones as well which is why I don’t just take those measurements and I have not dissembled it yet.

It looks the same but I know, when it comes to carbs and most engine parts, 1 millimetre can make a difference.

If anyone happens to know where I can find confirmation on the Mikuni in my bike, the seat dimensions or perhaps has one they can measure will be greatly appreciated. I also need to know the Feed hole size

Carb thread size

Could someone tell me the thread size for the main jets on a Hyosung gt125r the ones I bought are too big thanks