do I need a jet kit?

[eclipser2001]

I spoke to a mechanic at a Britt Motorsports here in Jacksonville and he said as long as I'm not getting a full exhaust, I don't need a jet kit. Well some members on kawiforums.com said that I more than likely will need a jet kit. All I have is a K&N air filter. Just looking for oppinions.

[aussieidiot]

yes and no.

basically you can change the exhaust and might get 1-2% on its own.
change the air filter and you get 0-1% increase.
change them both and you might get 5% increase if your lucky.

do the jets to suit and you'll get the most of the the package, maybe 10%.
jets on their own will do bugger all.

all of this differs per bike too.

i got a smoother curve and 3% top end power with an end can and air filter. if i put a power commander on its possible to smooth it out more and gain 12% across the range. power commander is the FI version of your jets

[eclipser2001]

Instead of re-jetting , can I just shimm?