Reply To: Gt250 Naked 2005 model carb vacuum issues

[Jacques Giani]

Hi Marcel. Bike is standing in storage. There is no tap or pump. There is a tap on the bottom of tank with 1 outlet for fuel. There was another outlet as well on the tap but the tube is gone. I believe this is where the one vacuum line goes to. So from this tap, there is a direct line to fuel intake on carburettor without a filter. That’s basically all there is. I’ve attached vacuum lines to the carb mounting rubbers but closed them off. This makes the bike rev and idle high at 3000 rpm. If I open the vacuum lines the bike idles fine, but back fires. The vacuum lines on top of carb is attached, but also just open. What I see on vacuum diagrams is that some vacuum pipes go to the fuel pump…which of course is not there. I think the issue of the bike running out of revs at 8000 rpm is due to the fuel pump that’s not there as there is not enough pressure to supply fuel to carbs?? Problem is that there is no indication of where a fuel pump would of been and getting spares in South Africa for Hyosung is extremely difficult, even 2nd hand spares. Other option is to install a fuel pump of a car…but not keen on doing that as well.