I mean you disrespect but.......why did you buy a used helmet?
Here's why I'd never buy OR wear a used (even a buddy's) helmet. Helmets are only meant to take ONE hit, not 3, 5, or 10; only ONE. And that's the reason I won't wear someone else's helmet, as you don't know if they crashed in it or even dropped it. Helmets are surprisingly fragile, as you can damage one by just dropping it. The way helmets protect you is with the foam liner, so if someone already compressed the foam (by crashing or what have you), there won't be anything left to compress if you end up crashing. Well besides your head that is.
If not having the money for a brand new helmet is the problem (usually mine
) try getting last years model on clearance. Here's a good site
www.motorcyclecloseouts.com Remember a new $40 helmet is better then a busted $300 one.
Ok end
, sorry it's just a touchy subject for me, I've had to many
s this year.
And to answer your actual question, yes not all helmets come with removable pads. That usually comes with higher end models.
How can i tell if the foams compressed? None of the crashes very hard, and the foam is totally in tact.
There isn't an easy way that I know of. On one of my helmets the complete foam shell had broken loose from the outer hard shell and the foam was "soft" on the side I hit. However on the latest incident were I actually got knocked out for a couple seconds, there's no visible damage minus the scratches. Won't be wearing it again though, my head/brain's worth more then that. 
