Hi everyone,

Today I rejetted my 2008 GS500F, installed a K&N lunchbox, and a Yoshimura slip-on.  10 hours later (stripped/repainted exhaust and had to Dremel ALL of the carb screws, ugh)...and the bike started right up, and seems to be running fine, if perhaps a little rich, might need to adjust mixture screws.

Followed all the tutorials here, but was not prepared for the device I now know is the "PAIR" system.  For lack of knowing what to do at the time, I just stuck some shop towel over the end of the hose and let it hang under the filter where the valve breather hose is also routed. 

Is this ok?  Do I want some beefier filtering on there ASAP, or is it ok for a few rides with the shop towel?  Do I remove the thing entirely, if so, do I need to plug the holes it leaves in the cylinder block with something?

You can remove the entire PAIR system. Suzuki Hayabusa banking plates fit. Go halves with a mate as you only need two.
http://www.ebay.com/itm/110625140511

Or take your current PAIR hoses, cut the ends off and either weld the closed or use JB Weld to seal them up. Ten reinstall them back on the head

All the pair system does is puff air into the exhaust. The bursts if oxygen will finish burning unburnt gasses.

Ditch it. Means nothing unless you are with the EPA.