K&N Filters.... Foam or not to foam that is the question

[Mono]

Hey Guys,

I put some K&N filters on my SP2 over the winter... I also fitted a PC. I wasnt sure if I should of removed the red foam restrictor things from inside the filters or keep them in.

I left them in for the time being and the bike seems to run nicely... but I find it strange bunging up an air filter with red sponge!

Any one had any experiences with this?

Cheers

Al

[Sppete]

HI Mono
K&Ns on a std set up have too little back pressure and cause an irregular flow of air over the trumpets. The foam has been added to combat this. Folks were giving them a bad name because the bike was producing lees power and even rougher running Not the kind of thing you want when trying to sell an expensive go-faster bit
A free flowing exhaust or a custom map and it's not a problem

Pete

[Mono]

Cheers Pete,

That makes sense, I have a set of arrow cans that are quite free flowing

I think I will give it ago with the red foam in for a few weeks then take it out and see what difference it makes. I had to put a PC map of K&N filter + Scorpion cans as I couldnt find a Euro set up with my configuration which was odd.

I was looking at the best map to get rid of the crappy throttle between 2-3000 rpms and this seems to have cured it nicely and the idle seems to be smoother now also but this could be a combination of cleaning the throttle bodies/ fitting the PC and K&N's.

Cheers

Al

[wild01]

I'm not saying this to degrade the K&N's but I've read up a bit about filters and test have shown that the standard Honda filter for the SP allows more than adequate air flow. Adding after market filters can give considerable under performance without proper tuning. Mind you, saying that the K&N's don't need replacing, just clean. oil and go.