Bed liner. Seriously?
You might want to actually check it to be sure it IS fuel proof.
it might not wash off the bed liner but i'd almost put money on it that it will change the finish where the fuel hits it.
You don't need to use hvlp to get a nice paint job on small shit like a moped.
go to your local auto parts store and pick up a can of Dupli-color Perfect match automotive touch up paint in your favorite color.$6. Then go to where they sell PPG products(ask around at the local body shops where they get their paint from. they can also put any color you want in a spray can) and you can get a can of clear coat that has hardener in it, and you can spill fuel on it all day long.
it's a special can that has a pin in the bottom of the can that releases the hardener into the clear inside the can. once the hardener is released, you have like 24 hours to spray it. any left over will harden in the can.. i think it is a 16oz can and sprays like a paint gun, not like a can of hair spray. well worth the $26
As usual, any paint job is only as good as the prep work. use a high build sandable primer. wet sand with 400-600. re-primer again if needed and wet sand again. once you have it all nice and dreamy smooth, clean and dry it well, then hit it with a few coats of the color base coat after blowing off any dust before spraying. Do NOT sand the base coat. then hit it with the clear coat. you should put the clear on within 24 hours of the base color to get a good bond. ever seen cars from the 80's with the clear flaking off?
The clear comes out of the can very heavy. be careful not to spray too heavy that it runs. use a light to observe the "gloss" as you spray. lay it on just heavy enough that it flows, smoothing out the 'orange peel'.
Dont do like most cans say and spray from 12 inches away. it just wastes paint and ends up with a dry finish and orange peel. 6-8 inches away starting before one side of the part as you move to the other end and past the part, moving moderately quick. if you do have any imperfections after it drys, you can wet sand with 1000-1500, and buff with polishing compound.
i've done many motorcycles over the years with 'spray bombs' and nobody ever believes i did it with a can till they actually see me do it.
if you want to destroy yet another vanishing classic REAL moped, spray that bed liner shit all over it. maybe you can get a 5 gallon bucket of it and just pour it on. you should feel real proud of what you've just done when you stand back and look at it.
Or you can just do it right for not much more money.