Bike wont start unless i take gas cap off first??

[Dht1998]

So i discovered that my Vader wont start unless i pop off the gas tank cap first, after i do that it starts right up and runs perfect, you guys have any idea on how i can fix that? :hmm:

[Narofive]

I have the same problem with my Vader, but the solution was to squeeze it on the side of the gas cap and the vacuum comes out, after that I can run without problems, it seems that some ventilation hose is not doing its job, when I remove the covers I will look to see how to solve it. Have you tried to squeeze on one side of the lid without opening it to see if you can hear air coming out?

[Oddball Matt]

Your breather hose is either clogged or kinked, happens easily when putting the tank back in place after a service on any motorbike. Probly easiest is to take the tank off and try blowing into the hose that should be dangling freely under the tank (after removing it from the tank) if that doesn't help try poking the breather with some sort of a metal wire or sth to unclog it, don't recommend blowing into the breather as you'll be shooting whatever's in there into the fuel (it might be rusted)