View Full Version : Gas cap help

07-15-2012, 10:53 PM
Im just getting things running,I have a 650 unit triumph with an aftermarket Harley tank with flush mounted cap. There is no vent hole in the cap, should I drill one or doesn't it matter ?

07-15-2012, 11:59 PM
it always matter, vents are important unless you want to putter out on the highway in fourth when you empty your float bowls

I'd just stop in the harley store, tell em your tank year and type and say you want something that vents well. usually about 10 bucks

07-16-2012, 12:13 AM
some of those tanks have a vent tube that comes out on the bottom of the tank,

07-16-2012, 5:39 AM
Try using one of these:


Or, you can order the same thing and the drill & pipe tap from McMaster-Carr. Pretty easy to do, took me about 10 minutes.

You can just drill a tiny hole thru the gascap, but you may get a tiny amount of gas coming out when the tank is full.

Good luck.

07-16-2012, 6:16 AM
Tiny hole , like maybe 1/16" or so.

07-16-2012, 7:54 PM
Thanks for the responses, I'll check into another cap

07-17-2012, 9:57 PM
Lowbrow did a how to write up in their second catalog/ magizine. They sell a breather that can be installed in the top of your cap once you drill and tap a hole. Check out the tech section of there website.


07-18-2012, 8:47 AM
I have a custom cap with a 1/16 hole and filter in it. If I fill the tank up it squirts out when I'm riding.