I recently ordered a new OEM filter for Thumpy since the old one was looking raggedy. I remember reading in here somewhere that there's nothing to be gained ditching the airbox and swapping a pod or other open filter. Is that still the conventional wisdom now?

Is the airbox sufficient for the engine's performance range?
Or does ditching it help matters?

I ask because since reading that old posting I noticed many folks in here are running open filters with no airbox.

Search for the thread where DragBikeMike posted his airbox and filter tests, along with the mods he tried. The airbox is more than capable of flowing enough for a hotrod in the 40 plus HP range.

I'll try to find what DragBikeMike wrote about. Thanks.

Mike, this old post tests several modifications to the airbox.  It should give you some ideas for mods to your airbox.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1523302904


This old post tests all the pertinent filter elements.  I personally like K&N.  Been using them for 50 years or so.  Always worked great for me but they are expensive.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1543600189

This more recent post gives some details on setting up your airbox for a cylindrical filter.  It will work with just about ant cylindrical filter (K&N, UNI, etc.).  It allows retention of all the stock mounting for side covers and igniter box.  It's about as good as your gonna get for air flow.  Cheap too.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1583103640/0#12

I see you have a little more displacement plus a tad more compression along with a souped up bumpstick.  If you have improved your exhaust too, more airflow is in order.

Looks like your project is pretty close to blast off.  You certainly have plenty of stopping power.  Are you fixin for some high velocity operation?  

DragBikeMike wrote on 05/15/20 at 14:50:42:


Oh heck yeah. That was the reason for the desperate search for stoppers, so I can go faster  
I did make a promise to make my bike safer before I made it any faster. Promise fulfilled. Learned some valuable lessons from riding the 110HP Ducati. I've got its stopping power now. I'll never get its hp from Thumpy but I'll see how far I'll get. 40 hp would be cool!


So in the near future I will be eyeballing intake and port mods.
Thank alot for taking the time to post all those links. I'll study up!
And try hard not to break or strip anymore bolts!

I ran my bike with a 95mm Wiseco, ported head, dyna muffler and a performance cam.  I ran the bike for a year in that configuration withe the stock airbox and stock carb......it ran great!

While I was breaking the piston/cylinder in and didn't use a lot of throttle or high rpm.......I got mileage up into the 60's - later on it was in the middle 50's for normal rides.

The stock airbox is a good design for the stock engine - and even for a mildly modified engine.  It is quiet, keeps water out of the engine, and also functions to dispose of the engine breather air.  When you remove it and install a pod filter you now have a way that water can get into the engine when it rains or you wash the bike.

I would recommend that you keep the stock airbox if you can as it works well - it should not be one of the first performance mods you do....it should be one of the last.

I also run the stock( but slightly modified) air box even with my tuned intake for it's obvious advantages, I can run the stock breather hose and drain, and no water enters the carb because I use Oldfeller's air filter installed in the rear of box where it is protected from rain or washing the bike by being centered between the frame and above the rear fender.  the bike looks completely stock

Philthymike , sorry it's not and I'm not sure it would work in exactly the same way for anyone else . I have changed fenders , seat and shocks on the bike, full HD rear fender that is bolted to the lower 2 stock bolts but leans backward to lessen the height between the tire and fender caused by 11.5 progressive shocks and allow an HD seat to sit flat to the upper frame rails and conform perfectly to the curve of the 16" fender.  That allows the top of the air box gap to be greater and room for the filter to work in that area.
    The length of my intake from the intake valve to the 2" pvc    pipe extension I used in the stock hose was about 15"  but this should be your choice as the length determines the areas where the boost in EV occurs.