Oil Pressure ?

[StuNVA]

I changed the oil on the Hayabusa today and noticed two things, the oil wouldn't drain out quickly unless the oil filler cap was out, I thought funny but fair enough. Then after I was finished the change and ran it for a while and went to top it up as the oil filler cap became loose it sucked air in like there was a reasonable vaccum there, is this normal for the Hayabusa, I've never noticed it on any of my other bikes.

[StuNVA]

Blocked crank case breather ??

[BANDITROD]

i reckon you might be right stu it sounds odd unless it has block off plates fitted maybe

[StuNVA]

I've been looking at a few diagrams, would it be possible that someone has connected the crank case breather hose and the pair hose from the air box together as some kind of mod ? That's what it looks like to, I've asked on the Hayabusa forum I'll see what they say ?

[StuNVA]

It doesn't seem to hurt it running, is it a problem.

[BANDITROD]

thats the idea of block off plates mate

[StuNVA]

From Hayabusa.org
The crank vent/pair mod is combining two systems to put suction on the case. If you just remove the PAIR, you will not touch the breather tube. The Crank tube comes off the top of the crank case above the tranny and behind the cylinder bank. You get to it by lifting the tank. That tube goes to the airbox I think. The PAIR also goes there for clean air to inject into the exhaust. Someone came up with the idea to connect the breather tube straight to the PAIR suction tube to draw vaccuum on the case. This is supposed to create a better ring seal and more HP. It sounds plausible but it would be messy to throw oily air into the exhaust. I just scrapped the PAIR and the bike doesn't backfire at all now

[BANDITROD]

sounds like its meant to be then mate

[ALBI]

To be or not to be !!
That is the question!