Busa PAIR / Crankcase Vaccum ??

On the Busa (K1) before I got it someone removed the PAIR line from the airbox and joined it to the crankcase breather, this has created a vacuum in the crankcase which is evident when you undo the oil filler once the bike has been turned off.

I am going to remove the PAIR gear from the front of the engine. This would then mean I will need to put a crank case breather / filter on the crankcase so it would eliminate the vacuum.

I was wondering is the current setup potentially robbing me of horsepower as the pistons may have to be working against a vacuum. ?

When I remove the PAIR would I need to retune the engine as it could be more "free flowing" ?

Some say that using the pairs to create vacuum increases horse power. Im still not convinced. No need to retune once you remove it all it really odes is pump fresh air into the exhaust. The crank case breather should go to the air box

From a quick search of www it seems its a common enough thing to do , with gains of 3 to 4 rwhp spruked all over BUT there is also a good few throwing up warnings of possable issues with big end bearings going to toast after a big run at the drags. (I didnt see a single crank photo in my 10 min search though.

Several people have also run electric evac pumps to do the same thing as the PAIR to vac pump deal specificly because there are power gains (slight)

As far as retuning (I doubt it) its only stuffing air into the exhaust to clean up emissions , From what I've seen the only real reason to remove the pair system is if your fitting an aftermarket exahust without PAIR attachment holes or if you want to save some weight.

There's a bunch of shit on the front on the engine, probably 3-5kgs of stuff bolted to the front of the engine associated with it, if it's not doing anything important maybe it shouldn't be there.
If it adds horsepower then maybe I'll plumb it up and include the crank case breather and ditch the other shit and just run the breather straight to the PAIR holes ? Would the this be a problem ?

The reason I ask is I was watching Speedweek and they were interviewing a guy and he said the last thing he wanted was to create a vacuum in the crank case, it just got me thinking, I know the Busa isn't a a nitro burning 5sec 1/4 mile muncher, but what he said started to make sense. He said the vacuum would actually rob horsepower as the engine was working against it ?

I don't think the PAIR valves create enough vacuum to have a negative affect on the HP. The Kwakas have the KLEEN system which is pretty much the same thing and they've been plumbing the crankcase breathers into the exhaust for years with no problems. I did it on the ZX9 and I don't know if it helps or hinders HP, but it seemed to spin up quicker (seat of the pants dyno).

Worst case scenario is if it doesn't work, just block the PAIR valve and call it done. And you won't need any re-jetting / mapping if you remove the PAIR as it's after the exhaust and doesn't affect the tuning.

Take it off and keep it in a box. You are better off shedding the weight than the very small (if any) HP gain some say you get