Fuel overflow



  • Anyone able to help me out I've pulled one of my older dt125r out today to find it had no fuel in it but I know it had fuel plenty of fuel in when I left it anyway I've put fuel in it and the carb is pissing fuel out of the overflow if I run the bike it's not a issue any pointers would be much appreciated I've opened the carb up and the float height is correct



  • I've got this on my VHSA carb.

    Very odd indeed.

    If it's been sitting a while I find that when you first turn the fuel on it doesn't shut the float valve.

    IF you take it up the road for a quick blip it sorts itself out.

    My guess, sticky float valve.

    Just dismantle it and give it a proper good seeing too.

    Ultrasonic cleaner is a good one.



  • @calum said in Fuel overflow:

    I've got this on my VHSA carb.

    Very odd indeed.

    If it's been sitting a while I find that when you first turn the fuel on it doesn't shut the float valve.

    IF you take it up the road for a quick blip it sorts itself out.

    My guess, sticky float valve.

    Just dismantle it and give it a proper good seeing too.

    Ultrasonic cleaner is a good one.

    Only one thing it can be, needle valve is sticking or more unlikely but possible floats need adjusting slightly. Shouldnt need fully stripping if its running ok just overflowing when you turn it off with fuel tap open. Pull the carb off whip the bowl off, take the floats off and pull out the needle valve. Push it in and out a few times make sure its working and spray a bit of lube on it. Stick it back together then blow through the petrol pipe a few times with the carb upright you should be able to blow through ok. Then tip it upside down and gravity and the weight of the floats alone will close the valve and stop you from blowing when its working. Should be ok if this happens, do it a few times and should be good. If your going to leave them standing for any length of time let them idle till they run out of fuel so they dont gum up.



  • Thank you both I'll give it ago, see what happens hopefully it will sort it. Otherwise the bike runs really well



  • Your tap might be leaking ever so slightly as well. This combined with a worn float valve can fill the engine over time with fuel



  • @nottsbiker

    Aldi are / we're selling ultra sonic cleaners for around £25



  • Cheers lads it seems to of sorted itself out 👍



  • @dan28 sounds like a bargain 🙂