Automotive Threaded Funnel STL

I need a clean, ready-to-print STL file for a medium-sized (between 3" and 6") threaded funnel that will thread into the fill hole of dirt bike engine. 6” overall length and 20m x 2.5 thread pitch and one with 18m x 1.5 thread. I would also like it to have a small tube all the way down the inside for a breather

Please deliver:
• The finalized STL, oriented for easy printing without support if possible
• A brief note on the thread standard you applied (e.g., diameter, pitch) so I can confirm compatibility before printing

If you model in parametric CAD, sharing the source file would be a bonus for future tweaks, but the STL is the required deliverable. I will test-fit the print on my end; payment is released once the threads engage smoothly and the funnel channels fluid without leaks.