Edited per popular demand and technical correction...
I just put the K&N in my Sprint and was a bit disappointed in the fit. The groove that fits to the lower airbox is a little wider than that on the OEM filter. However all seemed to fit fine once I realized that I had not transplanted the OEM o-ring to the K&N. Note to self: Read the instructions!
I also noticed that the OEM filter was dirty only in a small central oval. The picture below shows the filter after running a partially shortened snorkel for a while. The dirty area was originally smaller.
On closer observation it seems that the intake snorkel protrudes into the airbox nearly up to the filter surface. There isn't much room for the airflow to fan out to the perimeter of the filter. I would think this makes the OEM setup a bit restrictive.
I mail ordered another snorkel just to have a stock piece and proceeded to cut my original piece just inboard of the airbox.
My next observation was that the resonator protruded far enough into the snorkel to choke off a good portion of the right hand cross section. I trimmed the nose of the resonator such that it fits flush with the inside of the snorkel. Of course this raises the frequency of the resonator since the airmass in the tube resonates with the enclosure volume.
This was after trimming the resonator snout. The snorkel was nearly closed off in this area by protrusion of the resonator.
So...
Steady state airflow should be improved. The resonator (and snorkel) are tuned to higher frequencies. Intake cross section should be increased. I am running a TOR pipe and the 20107 tune. My head pipe has the US spec precat which is fine as I have no heat complaints now with the TOR.
Bonus photo in case the thread still loads too fast.
T595.net has a link in the Performance Tips forum titled secondary air injection. There is a link to photos of CNC'd SAI plates.
He wants $100 shipped for them, probably 3x a reasonable price.
They aren't needed as SAI hardware can be disabled with rubber caps.
I bought them anyway.
Now of course the standard disclaimer.
Mess with your bike at your own risk.
If *you* mess up *your* bike, warranty etc... Remember it was *your* doing. I will not accept *your* responsibility, feel bad or even particularly care.
Sorry about that.
[ This message was edited by: CLB on 2006-11-19 12:11 ]
I just put the K&N in my Sprint and was a bit disappointed in the fit. The groove that fits to the lower airbox is a little wider than that on the OEM filter. However all seemed to fit fine once I realized that I had not transplanted the OEM o-ring to the K&N. Note to self: Read the instructions!

I also noticed that the OEM filter was dirty only in a small central oval. The picture below shows the filter after running a partially shortened snorkel for a while. The dirty area was originally smaller.

On closer observation it seems that the intake snorkel protrudes into the airbox nearly up to the filter surface. There isn't much room for the airflow to fan out to the perimeter of the filter. I would think this makes the OEM setup a bit restrictive.

I mail ordered another snorkel just to have a stock piece and proceeded to cut my original piece just inboard of the airbox.

My next observation was that the resonator protruded far enough into the snorkel to choke off a good portion of the right hand cross section. I trimmed the nose of the resonator such that it fits flush with the inside of the snorkel. Of course this raises the frequency of the resonator since the airmass in the tube resonates with the enclosure volume.
This was after trimming the resonator snout. The snorkel was nearly closed off in this area by protrusion of the resonator.

So...
Steady state airflow should be improved. The resonator (and snorkel) are tuned to higher frequencies. Intake cross section should be increased. I am running a TOR pipe and the 20107 tune. My head pipe has the US spec precat which is fine as I have no heat complaints now with the TOR.
Bonus photo in case the thread still loads too fast.
T595.net has a link in the Performance Tips forum titled secondary air injection. There is a link to photos of CNC'd SAI plates.
He wants $100 shipped for them, probably 3x a reasonable price.
They aren't needed as SAI hardware can be disabled with rubber caps.
I bought them anyway.

Now of course the standard disclaimer.
Mess with your bike at your own risk.
If *you* mess up *your* bike, warranty etc... Remember it was *your* doing. I will not accept *your* responsibility, feel bad or even particularly care.
Sorry about that.
[ This message was edited by: CLB on 2006-11-19 12:11 ]