Gas cap not venting?

[Patch]

So I searched an found nothing so... My bike will start to run lean after a while. So when I look at the fuel line, it has big air bubbles.

While the engine is running, I open the gas cap and lift---VUALAH the bubbles are gone.

So I know my gas cap isn't venting properly--would it be ok if I drilled a tiny hole in the top?

 

[Guest]

Yes. Use a small bit and stop as soon as you pierce the top of the cap. I did it to both of my bikes before I ever ran them.