Reply To: Fuel tap for GT125 Comet
Vacuum should not be blanked , the tap will need it and the fuel pump is actually needed too. The 125cc uses a DF52 Mikuni Pump that was made for the Hyosung family , so the GV650 actually uses the same pump, it has a flow rate of about 80ltrs per hour, no way the 125cc will maximize the fuel pump , infact it is needed to help it sustain speeds at the top gear as it works on vacuum pulses from the inlets. Check your inlet O-RINGS , usually we check the O-Rings under the inlets before replacing anything else. China inlets = Chinesium , it won’t beat the OEM quality but it will get you on the road asap until we find the super rare originals! Check your oil filler cap, sniff inside hard, if you smell fuel , it sounds like fuel tap is “wide open” after engine is switched off , would suggest future problems with piston rings or hydrolocking too – The tap may have a burst diaphragm Just some of my thoughts , hope any of what i said made sense to you ? Regards
As mentioned the way it’s set up IF I removed the blank from the vacuum pipe the fuel would not exit to the fuel line as there’s nowhere to plug the pipe into on my bike lol, the “vacuum tap” is forced open to a universal tap to turn off/on which is why I asked if any of you knew where it connects to from the tank.
^Just to further touch on this, mine does not have the vacuum to the tank as default, it wasn’t there to begin with as it had the manual tap mounted to the frame….. Obviously I know this is not ideal however how it’s set up now is as close to the original tank as I could get it in the moment (and really overall? without knowing where the vacuum pipe connects to). It being blanked off isn’t an issue since I control on/off with a universal tap so the vacuum right now is not needed at all. It’s set up as it should/can be right now when comparing it to the original tank).
Yeah the originals are as rare as the petcock I can’t find thus I have no option (all of us are in the same boat ey 😯 ).
The fuel tap is DEFINATLEY NOT wide open, my bike is surging when idling to around 3 to 4k and no adjustment on the idle screw will fix this, it does sometimes temporarily however it starts again on my next stop more often than not (I’m pretty sure it’s a vacuum leak).
I know the fuel tap is definitely off when I switch it off, I sometimes would forget the tap previously and the fuel would sit on one or both pistons and hyrodlock and I havent experienced this with my current set up at all. I’ve persisted through fuel leaks to get to this point at the tap however I have fixed this by ordering a bigger tap as the fittings on the ones I ordered clearly weren’t the mm they said they were.
I’ve owned this bike since 2012 I’m not new to any of this hah, are baz and sim not around anymore? Are you still in touch with James (BD – cillit banged an engine if you remember)?
Anyway yeah it does make sense but I think you may have skimmed over what I originally put.