gas cap leaking

[Tapartacus]

hi everyone was reading an earlier topic on the subject of gas cap leaking. I have asked this question before but I guess didn't really understand the answers.  My gas cap leaks though the key hole. However gas cap doesn't always leak, seems random. I've pulled apart the cap and can't see any real issues, cleaned everything up as well. Someone mentioned a "flapperectomy?" The orange flappers seem fine. The bike is from California. Also I read an article of someone drilling out the vent holes under the flappers and and the lock slide to allow better airflow to the carbs, he swears by it actually. Quote:

The following mod has an impressive results in order to its simplicity and quick fix. Basically, the mod helps the carbs to absorb fuel from the tank, minimizing the deposit vacuum force. Then , the fuel flows more freely and , in consequence, you get faster engine acceleration.
HRC, Honda Research Corporation, used this trick in its 60, 70 & 80 race bikes. Hence the name of the tick

The theory is simple: you must maximize the tank vacuum mechanism, but taking care that the fuel and the fuel emissions don't exit from the tank cap.

PHOTO 1: you can see the 3 screws to remove. Drill the little hole that you can see in the close mechanism cap only with a drill 1 size bigger. Be careful don't disturb the screw that you can see at the left. It holds the cap lock mechanism, a little spring with a microscopic ball that jump from the place at the moment that you touch that crew, and after are near impossible to refit.

PHOTO 2: covered by the cap there is a spring. Be careful don't lost when you extract the cap. And take care when fixing that the lock mechanism works. You can see too the cap hole to drill.

PHOTO 3: you can see the piece extracted. It is not needed to extract the big grommet around the cap, even although it is dismounted at this photo. Be careful don't break that black grommet gasket

PHOTO 4: we must extract that orange membranes fitted in the plastic piece. Be careful when refitting that plastic piece because it has a fixed way: you can see the air conduct way grabbed on it. I've drilled the two little holes that you can see at the plastic piece mounting hole with the same little drill than I used to the hole at the photo 1.

Fit everything back and VOILÁ!. AMAZING!! Outright, addictive and awesome power, Warp-Speed acceleration, less vibration and with less jumps at low revs. And combined with the other mods my bike feeling is like a turbo is fitted when the needle passes 6500 rpms. By end the engine feels like the FJ 1100 one!, only that with more low down torque and power. really, it is near a miracle!!!!!

Sorry that was really long, but you get what I mean. Any thoughts?
Andrew

PS link to page quoted: http://www.fj1200.info/Home.htm article is at the bottom of the page under "carb tuning"

[FJSpringy]

I did this mod many many years back when Spanish Alf put it on his web site, I am one of Alfs biggest fans, but while the mod is a good one I suspect he over sold the "really, it is near a miracle!!!!!" aspect of it. It is easier to do the mod than read about it so its worth doing it just don't expect a tubo boost 

[Tapartacus]

Any suggestions on the key hole gas leak? Anyone tried the aftermarket gas cap?