I have a CBR125. I have just bought it. I filled it with fuel and now it leaks from a pipe underneath the bike.
I no nothing about bikes or how to repair them, but I would like to know why it leaks.

Nick, August 2009

there should be a little screw on the bottom of the float bowl which empties the float chamber try tightening it...

MunchiesxD, October 2009

the carb has a float in it that floats on top of the petrol in the float bowl it also has a needle on it that blocks the float needle seat when it rises on the fuel, its linked to the fuel tank supply,sometimes a piece of debris or rust can get between the float needle and the float needle seat and stop it from shutting off the fuel supply so it will rise up above its operating level and then flow out of the overflow pipe whci is what you can see happening.a cure is to either take the float bowl off the carb and clean it out or lay the bike on its side for 30 secs or so and then stand it back up to see if its dis-lodged the debris it will sometimes just move through the valve to the bottom of the float bowl.good luck mate.adam

the ped med., August 2009

This pipe will be a drain from the carburettor float chamber....basically, the carb is over filling with petrol, and the excess is leaking onto the ground. The cure is to take the carb to bits, and clean out the float chamber and needle valve assembly. Its also a good idea to turn off the petrol tap in the mean time, if there is one, when the bike isn't being used.

John, August 2009