I have a dual sport XR600R and as I am looking at the top of the air box I am beginning to wonder how in the world any air get in there. Between the BD dual sport wiring, battery and electronics it would appear to have cut off much of the pathways for air to get into the air box. My CR500 had the whole top of the box open from the factory and the 600 has a relatively small 3" by 6" opening from which to draw from by comparison. I have to imagine a 600cc bike would need at least as much air.

Has anyone modified their left side number plate/air box cover in a simular manner as the 650 owners do (cut out with screen over) and if so, any difference in performance?

There are a lot of XR600, 650L guys that do that as well. This is what i did to my numberplate to get more air in there.

I also know that some people cut holes in the other side of the airbox (right side) to allow even more air to get in but I didn't.

On a side note by doing what I did and having an extra side plate with no holes drilled in it I was able to figure out my jetting quicker because I could limit the air going into the bike by switching to the "no holes" number plate and see if it ran better than with the extra air from the holes. Then I knew I needed to go up on my main jet when I was running with the open airbox so i didn't have to swap jets around as much to find the best ratio for my bike.

http://www.thumperta...789#post8081789

I dynoed my XR600R and XR650L in various states of airbox and besides changing the jets I needed to maintain my target AFR, the HP remained about the same. Take it for what it's worth but I don't want my piggy drinking any muddy water in exchange for .03 HP.

I just picked up a 1997 XR600R with an Edelbrock Qwiksilver carb and White Bros exhaust. My background is with the CRF250x.

On the 250x's we are cutting our airbox open and rejetting the bikes for better low end grunt, cooler running temps, easier starting, and less bog/stall problems.

I just cut the airbox on the XR600R to about 5"x5" on the top, running a UNI filter, and richened up the Edelbrock a bit. I also increased the accelerator pump action on the carb.

The bike seems to have a noticeable increase in low end grunt, easier to get the front wheel off the ground, runs great at altitude, no decel popping, etc.

My long winded approach to my question is this. Are other XR600R owners doing this mod quite commonly to the airbox?

if u look closely at the upper margins of the first picture just above the battery i also have "vents" on the right side of the airbox as well as the left side cover/number plate... :thumbsup:

...with the R carb and battery relocation mod on my bike it wud bog at WOT because it wus starving for air...with my setup i promise u it's doing better than a 0.03HP gain...

thumpers are quite forgiving when it comes to drinking water :worthy:besides there is always an opening somewhere :smirk:





:cheers:

where does one get them watchamacall`em's in pic 2 ?

BMEPdoc said:

crfsonly.com sells them.

brokenrod said:

I bet you would find that the 500 moves a lot more air mass, so it would actually need a bigger intake opening than the 600. With that in mind, the stock airbox opening is around 4.7 x 2.0" with a flow area of 9.4in², equal to a 3.45"/87.9mm tube. That's not exactly small.

The 500 made much more power than the 600 so it would seem fair to expect it to need more air.

My point is this and maybe it only applies to my bike but here it goes. Being dual sported it now has the battery and all the wiring residing in the flat are just ahead of the stock air box opening. When you look at the seat base you can tell that it was designed/incorperated into the overall design to seal out avenues for mud and dirt to enter in. My question is not so much is the opening of the box enough but with all the garbage on top of my box in addition to the factory efforts to restrict debris getting into the air box, just where is the bike pulling air from? The seat base itself rests on the frame the length of the seat. The seat has a rubber flap that seals off air flow from that direction,the battery/wiring does a pretty effective job of taking up the area twords the front of the box so basically the air flow to the box is cut off or restricted from all sides. In view of this does it make sense to vent the left side number plate like the above XR (from what I can see nice bike by the way)?

BMEPdoc said:

the black plastic ones w/foam filters are Uni PreFilters...CycleGear and other stores carry them...

...the metal ones can be found at electronic supply stores or there were some on Ebay a while back.

a UniBit does the best job of cutting holes in plastic :thumbsup::thumbsup:


:cheers: