I have a Brand New 2009 Ninja Kawasaki 250 and have been experiencing a high pitched noise that seems to be coming from my Gas cap. While riding my bike I hear the same high pitched noise. When I turned off my bike, the noise was still there and it was constant. Once I opened my Gas Cap it released the pressure and the noise went away.

What could the problem be? How could I fix it? I think It might be a gasket in the cap that's letting out some of the pressure, but I'm not certain. Any ideas?

 

I think its just the opposite, Your cap is not venting like it should. Its building up too much pressure and then trying to get out.

 

That does make sense. Do you know how to go about and fix that, aside from replacing the cap?

 

The tank doesn't normally build up pressure. As fuel is removed it creates vacum and air is pulled in through the vent to equalise pressure. Otherwise the vacum would stop fuel flowing out of the tank and cause the engine to stop - it's not an uncommon event. In hot weather the air inside the tank can expand if it's in the sun (and to a lesser extent so can the fuel) so under those conditions air is expelled through the vent.

Check that the vent is not blocked or obstructed. Some do whistle as air passes through, especially if the tank's got hot and is expelling air, and there's not always much you can do about it.

Rob

 

I to have heard my bike make that noise but when I open the cap the noise goes away so I believe also it's in the venting but have not had a reliability problem and if the noise is not to loud let it be and talk to your service department about it good luck