Sorry everybody got mine in today and it is way too big for the valkyrie. I tried the spectre website for the correct one but no luck.
My gasket started leaking a couple of years ago, I didn't want to pay $30 for a new cap either.
I carried the cap into Autozone and matched it up with an automotive cap that fit for about $7.
That cap couldn't handle the pressure, it leaked around the flip top, So I took the gasket from it and put it on the Valkyrie cap and it's been doing fine.