Motovox Predator question

I'm installing a stage 3 Hemi predator kit on a Motovox Mbx11, including the PMR engine mount.

Everything is very straight forward even for a marginal mechanic like me, but I have a question: I haven't tightened anything down yet, but it seems the fuel cap sits right underneath the cross bars, and just high enough that I can't easily get it on or off (needs about another 1/4-1/2" clearance). With everything loose I can do it, but when everything is tight I don't know if it will work.

There are a lot of Predators on Motovox bikes, just looking for tips. It seems if I wasn't using the engine mounting plate I'd have the clearance because it's about 1/2" tall but it makes adjusting the position of the motor super easy.


There is a old version gas tank with the fill on the side.
There may be some on Ebay or maybe some one who is hopping up a Predator may have one. I bought one for one of my early Predators from a member here. It was a take off from his cart racing engine.
I appreciate everyone's help. Simple solution from HotRodMiniBike was a chrome low profile gas cap for $10. Shaun said he's probably going to include it in the kits from now on--works great. Here's a pic--it only sits about 1/4" above the tank and doesn't have the piece that extends down into the tank, so net space gained is about 1.5". 20150314_141041.jpg