A few years back I was doing some dyno tunning with my kawasaki and at the time some of the guys in the club were having a big debate on filters. So I decided to do a back to back comparrison of the bikes performance with the factory filter (a foam filter similar to the uni) and the K&N aftermarket filter.
The results supprised me as the bike made more power with the factory foam filter than it had with the K&N.
This wasnt one of those one run with each filter tests, I did multiple runs with each filter and made changes in the jetting and even ign advance rates. It just was that everyting I tried the factory filter outperformed the K&N.
I also used to do a lot of off road Dune buggy rideing and racing.
After a few years of dealing with dirt somehow getting threw the K&N a fellow off roader suggested I try a set of Foam on Foam filters from CB Performance. Once installed at the beginning of the season it was the first year I went the entire season without having to clean dirt out of jets. Not to mention that half the time I could get away with only cleanning the outerwear of the filter. Not to mention that I could clean both filters (dual carbed) in less than an hour and be running again.
So you guys can probably guess what filter is in my tthunderbird?
As for what to do with stock exhaust. Any part I take off gets packaged nicely and put away. The cost of replacement if something happens can be high. Not to mention if your like me and keep your bike for a long time you have to remember that as the years go on they wont be making aftermarket parts for it so replacement of those hog slayers might not be an option in 10 years and as with my kawasaki 900 the factory exhaust is no longer availible and the only option is to have a custom made set done at a big cost! Some guys in the zl club would pay serious money for the pipes I have neatly tucked away just for in case. Not to mention If I decide to sell a bike having all the stock parts actually improves you value and gives you the upper hand when negotiating.
When I go to buy a used bike. The offer I make for one with an aftermarket exhaust is always considerably less than what I will pay for one with all the factory parts/pipes. I really dont care who made or how good the aftermarket pipes are, if the stock pipes are not present the bike is worth less!
Last edited by paulfun; 10-22-2011 at 07:18 AM.