By BJAM 07/2003:

There have been several threads on the air box modification, some of late have been discussing the merits of leaving the standard air box bottom in place and fitting performance filters over the intake trumpets. One major concern regarding this method is the ingress of dirt and, more importantly, water into the air box bottom.

Let’s take a closer look at what is in the air box bottom, under the standard filter:

1. There is an air temperature sensor
2. There is an intake tube for the PAIR system
3. There is the crankcase breather hose venting through some plastic gauze. To hold the gauze in place there is a plastic pocket that is raised from the air box floor.

So what are the risks regarding serious water ingress? The temperature sensor can be exposed to the elements so no problem there. The PAIR system intake tube can be sealed off with no harm to your engine whatsoever - the only thing you loose is a crackle and pop on the overrun during deceleration if you have performance cans fitted. So really the only concern is the crankcase breather tube. When the bike is running the tube sucks and blows constantly to relieve crankcase pressure due to piston movement. As the filter gauze is held in a raised plastic pocket the chances of serious water ingression though this tube is minimal. You would have to be riding through a torrential downpour and flood and even then this system is under the tank.

So now for the good news. Did you know that there is a water drain plug in your air box? Oh yes baby, its there. In the service manual it states:

Note:
When cleaning the air cleaner element, drain water from the air cleaner by removing the drain plug.

Can you believe that! They actually expect water to accumulate inside your air box during normal riding.

Conclusion:
If you want to take your air box lid off and ride with just the base in place there appears to be minimal risk. Remember that you must have some form of air filtration in place as the life of your engine depends largely on this component. The design of the standard air box facilitates the draining of water as standard. You could simply remove the drain plug altogether and benefit from constant drainage after fitting your filters (Edit=AndyW: but unfiltered air would be drawn in!). Lastly, the risk to your crankcase through the breather hose looks fairly small if any. If in any doubt then pull the tube off the air box bottom and extend it to somewhere else on your bike where there will be no chance of letting in water. You will see this method with other air box mod threads on this site with pictures on how it was done.

So what about other commercially available air box modifications I might hear you ask? I have fitted the Renegade Air Kit to my bike. Renegade have put time and effort into making an easily fitted air kit that does the job admirably. The cost of the filters is very high and constitutes a large proportion of the Renegade kit. If you purchased them for yourself you would find yourself only saving a few pounds and would not benefit from Renegade's high experience in this field or even the infectious enthusiasm of the staff there. As they say, you pay your money, you make your choice.

No thread would be complete without the obligatory pictures so here is the first: The drain plug itself.

Secondly, how it looks from inside the airbox:

And finally, and sorry for the poor quality picture, how to reach to drain plug with the airbox fitted:

Do I need to add the final comment - I guess so. Please do these modifications at your own risk. I am not advising you to make these changes to your bike, just informing you of the possible consequences of your actions. Please make up your own mind on the risk and don't ever say BJAM666 told me so.

Jimbo77 07/2003:  This is the exact mod I was planning to do, and had started a thread here. I looked into the cost of the Pipercross filters, and was looking at spending almost 2/3 the price of the entire Renegade kit, plus freight. Now, the amount of work required would in fact be less by just adding the Pipercross, and I already found the drain plug on the stock airbox base, so I wasn't worried about water intrusion. My biggest concern was being able to get my hands around inside the airbox to attach the new filters, and the fact that I would have to cut the rubber flares around the throttle bodies from the stock airbox base. So, with much thought going into my idea, I decided to spend a bit more, and save myself the aggravation, and have my Renegade Airbox Kit shipping as we speak. Mind you, Jorge himself was quite accommodating in giving me info about what I wanted to do, and that impressed me enough to say to heck with the hassle, give Jorge the credit for his R & D, and order his kit. Cheers to Jorge.

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