there is a rubber seal in the schrader valve. being that close to the exhaust that gets very hot may cause the rubber to fail thus a leak down.
it may be way to close to that pipe.
First choice was to go to rear, but too difficult finding lines that were long enough at local stores. High quality braided lines are difficult to locate past 10" (please defer all dirty jokes to another thread...)
While close to exhaust, should not be heat issue. Went for 100 mile ride after doing this and while nipple was "warm" wasn't hot. Second, yes, if you want to adjust air during a long ride, you need to be careful of heat from heat shield on your fingers. I usually adjust just before a ride. I may add a 1 inch extender to take care of this problem. You can also angle it more away from exhaust as you can see there is room to spare before hitting clutch cable.
Now before some complain there may be too many connections to fail, I don't care. Too easy to replace a new extension or filler valve. A failure here doesn't cause me to stop riding like a clutch cable, only to repair a $1 part and 2 minutes labor. And while were talking about possibility of failure...WAIT UNTIL YOU SEE THE STUPID ANGLE THEY HAVE THE HOSE MAKING BEHIND THE FILLER NIPPLE! They have a beautiful curve with a retention clip on the fender, but have the hose almost crimped in a right angle behind the side plate!
Next step for me will be a Hydraulic clutch which will allow me to move it further away from exhaust, and either paint the clamp black or replace with a flat piece of metal mounted to the bolt on the engine bracket where the clutch cable will vanish from.
Anyway as I said not elegant, but cheap and easy and the braided line is designed for trucker tires, friction, water, heat...so I expect it can handle this.