[Closed] Solo air Recons - Quick Q

I obtained and servied a pair of these at the weekend. Decent forks.

But, do they have a 'negative air' chamber? Not a seperate one like Revs, but a self-charging one? I thought they did and it seems there is one when you pull them apart.

I upped the travel and pumped them up, but they seem very stiff and bouncy, even at low pressure (75psi) like a Rev/Reba that's not had the negative chamber pumped up....
Just wondering, they might be fine and working as intended, but I'd like to get them 100% before I sell them. Cheers! 🙂