Guys I wanted to run this past you. I've searched now for a while and can't find the information I'm looking for.

In-fact I'm not even sure an issue exists here I just found this odd and wanted input.

2005 Bruin 250
Details:
FMF Powerline exhaust
FMF Jet kit installed per instructions for this altitude
6-filtered airbox vents in lid
Stock paper/foam outer filter.

I installed all that stuff to give this a little more power and I have been very pleased with the results. Once installed it has run great, though its still slightly on the rich side as per sparkplug testing.

Now I just noticed something strange as I was doing a service (Fluids, air-filter, plug etc). I was thinking that I'd install a couple more airvents and a twin foam for a little more airflow and I noticed the foam in the airvents is dirty. I looked at the back side (the inside of the airbox lid) there is far more dirt on the inside side of the airvent foam than the outside.

Here's the part I don't understand. I re-installed the aribox lid and started the machine. I held my hand over the vents and felt quite a bit of air pressure pushing out of the vents. Kinda the opposite of what I expected..... I was kinda thinking I'd feel suction.

Is this normal or is something wrong that I just don't know about?

 

Anyone know if something is wrong or is that normal?

 

Could it be the breather, for the crank case, pulsing? If you disconnect the breather(for a test),....does it change?

 

I checked that when I got home. I'm really suprised at how much air that breather moves. Thats exactly what it is.

I was really sprised that for as much air as it moves, there isn't a filter on it. That really sucks in (and blows out) a significant amount of air and its plugged right into the air snorkel. Its getting unfiltered air.

I'm kinda thinking of doing a mod I saw here (as I was searching around). Removing the snorkel and running the breather into the airbox with a small filter on the end of it. Seems like a better setup to me......