to restrict the air intake.

less air intake = less combustion i.e. less pollution.

and less noise!but the holes don't bypass the filter!it would be too dangerous!

In drilling your airbox, you bypass your air filter. Unless i have the complete wrong end of the stick (quite probably) i was under the mipression the holes were to be drilled on the airbox access cover and on the other side in a similar position. If not...

...im happy to get my drill out.

maybe you are right, however I wided the air intake hole but before the filter!

The better solution may be to buy a stage 2

You don't bypass the filter. When facing the airbox, you will be drilling the 'airbox' to the left of the filter which is where air from the snorkel is routed anyway.

But yeah buy a stage 2, I hopefully will be soon.

Kev, does this reply mean that, as a short term measure, the Stage 1 and 2 filters can be fitted to an 08 bike, with the snorkel removed, and this 'lamba' thing should be able to sort out the fuel/air mixture??
If this is right, what adjustment would you recommend, as a start point, for the co? Bearing in mind the bike will have cans fitted too.
Thanks.

You could try some of these filters.

http://cgi.ebay.co.uk/motocross-AIR-...QQcmdZViewItem

Freeloader your statement is totaly incorrect, if you drill them as per my instructions you will be ok, you would be drilling in the prechamber before the filter. The air box is made up of 3 different chambers.

Chamber 1, before filter where the snorkel sits, safe to drill holes.
Chamber 2, is after the filter filtered air, do not drill.
Chamber 3, is below chamber 1 & collects water & dirt that enters chamber 1.

You can fit both filters, the O2 sensor will correct the fuel mixture under cruising conditions & when the motor is warm. The only problem is the O2 sensor does not work under all conditions & a fueling device is recommended to correct this.