2004 F4i performance upgrades
 

Hey everyone,

I've been doing some reading on performance upgrades for my bike, I would like to get alittle more jam out of the bottom end. What I've gathered is I need to change my gearing, I need to replace my chain so I figured now is the time to do it. Most recommended is a -1 front and +2 rear, my question is how badly does it effect speed at top end? I'm not too excited to loose top end in the first place but I know its the trade off for gaining on the bottom end.

Also, is the power commander really worth it? And is there anything additional I need to know if I add the power commander after changing the gearing? Bike has a slip on and K&N filter so no problems with air.

This might help your search
Gearing Commander ⚙

It will take a little of the top. Unless you are winding it out in 6th gear and going max speed, you probably won't notice.

The power commander is well worth it, especially if you have it tuned on a dyno.

The K&N restricts more air than the OEM filter.

Any recommendations for an air filter? Or would a stock one work fine

Since your changing chain & sprockets may as well get the smaller size 520 instead of the 525 or 530. Less weight robs less horsepower.

Stock flow pretty good. There are some other washable ones out there that flow better, but I can't remember which ones. I think bikemaster has a regular and race version... but don't quote me on that. If you look around the forum, you will find info on k&n being restrictive.

I use BMC air filters and although there has been no gains performance wise, I notice no drops as well! Intake roar is marginally better

Even with all the mods [full exhaust, filter, PC] you still won't see much HP gain. Spend the money on real performance, suspension upgrades!