Rotax 582 Radiator Cap WOES

[JustPlaneMike]

The 1993 KitFox II with a Rotax 582 model 90 gray head I recently purchased and now working on the conditional inspection . The Radaitor Cap was the 6-8 PSi one that needed to be changed to the 13 psi one. Searching all forums I was lead to a cheap alternative which was a Motorbike Radiator Cap A Triumph part number T2108005 I found one and ordered it For around $25. Great. well when I got it it was to small. was the information wrong? So much time was wasted looking for it I decided to go ahead and and order the Rotax part number 922-072 from Leading Edge Airfoil. Well guess what it to was to small and the Triumph was an exact match.
Leading Edge suggested calling KitFox cause he thought they shipped out the caps with the kits and that it was proably a standared automotive Cap. I was able to supply the Listed part number from the build manual E-62- Kitfox did not have a match for the Cap- He did search and found some histroy that Denny AeroCraft, purchased the radiator caps from a local parts store.They did not use the cooling system from Rotax. no parts number available. Wonder how much other automotive parts were used? I going to return part to Leading edge unless someone want to buy it, I also have the Triumph clone cap for sale.
So before I go to the auto parts store and They ask what vehicke is it for? so they can lookit up on the computer cause they don't know how to find parts otherwise.
Does any one have an autopart number for the automotive cap I need ?
Ill try to add photos
Ist photo is the Triumph Cap any my old Cap 2nd photo Triumph part number 3 filler neck on plane 4 My cap and the Rotax Cap,
Thanks for any feedback and hope this helps some of us with the older kits