yamaha ybr125 question??

[uzi_999]

Right, was fiddling around with the ybr this morning (against what everyone says, trying to make it faster/louder/etc.. ), and found a pipe running fron the exhaust into the airbox..

opened it all up, and (to put it into words) theres a pipe coming out of the airbox, going thru a one-way-valve/non-return-valve (in plumbing terms), and to the exhaust.. the valve only allows air OUT of the box..

Heres a somewhat technical quick diagram, drawn up in ms paint...

[arrow is direction of allowed air flow in valve, everything labelled, and roughly in position as is on bike, and red line is the rubber pipe]

btw, the pipe connector on the airbox is on the 'clean' side of airbox

Now i drew it up on paper, and could come up with two purposes for this being there..

1. The exhaust fumes get 'diluted' with air, so as it's not as bad for the environment..

2. The more air coming out of the exhaust (i.e. the higher the revs), is proportional to the amount of air sucked into the airbox..

Having disconnected this pipe (at exhaust end - not on airbox side, as that will have unfiltered air entering the throttle body (carb, or whatever it is called on an injected bike ), i found that it sounds AWESOME!! a bit too loud, but ermm, i could get used to it!!

Are there any dangers of having it disconnected? As no dirty air entering the combustion chambers (due to one-way-valve)..

Im assuming its like a hole in the exhaust.. I think it would affect the fuel consumption, and taken it for a quick ride, found it still accelerates the same (seems a tad bit slower above 40mph tho - maybe its just my brain playing tricks)

I also smell a sh*tty smell, fuel vapour it seems like..

However, its much louder, was wondering if it would harm the poor molested bike or would it turn the beauty into a beast (well, audibly )

Any ideas on what its for, what it does, and safe to disconnect (at exhaust end, AFTER the one-way-valve)

now theyl all hear me

thanks in advance