Changing Air Filter
 

Dose anyone know if changing the GZ250's air filter with a higher performance one will help increase top end and also not effect how the bike sounds and handles?

Thank you, Christian

2008 GZ250
2,853 Miles (so far)

welcome to the forum. I have not tried any air filter mods on my gz250 yet. I did do some on my gs500e. the k&n filter replacement worked fine without having to rejet the carbs. then I removed the factory air box and added pod filters and it dropped my top end and was sluggish between 1/4 throttle and 3/4 throttle. rejetting the carbs needed to be done to fix the problem. other people on this forum have posted good info on this subject. you might wanna read those. try the search engine to navigate through them faster. I hope I was able to help.

What is the top sped now?
Road, weight of rider, and weather conditions have more to do with top speed than and mods that you can do.

Most air and exhaust mods create more problems than make gains.
75 to 80 mph speeds are what most GZ's will do stock.

I agree. 80 is good, anything over 80 is a bonus but the GZ will not like that speed for long. A maximum cruising speed in good conditions seems to be 60 to 65 to keep the bike happy.
Trying to mod a GZ is not a great return for the time and money that can be invested. Ride the bike according to it's capabilities and accept them. If you need more speed and power then you need more bike under your butt. There are lots of slightly larger and just larger bikes to fill the requirements.

Qasual - The HWY in Vancouver is 80km/h and I usually do 55-60mph (88km/h-96km/h), the GZ is very happy with those speeds and not too much in the vibration department as well. As everyone else said, if you want more speed and power. You're looking at more of a bike.

You won't gain much in performance but you can save about 50% by using the Hiflo-Filtro Hfa-3503 air filter.It is a direct bolt in & will breath better than the OEM.Because it is more of a open design it will make the intake a little louder. :) ;)

yes, but you may need to change the main jet to compensate for the extra air.
I'm running:
mod air filter
140 main
2.5 turns on the pilot
and 16T sprocket
I am very happy with the results

ive done nearly this same mod.
EMGO Cone Air Filter attached directly to carb intake
(no air box)
135 main jet
2.5 turns out on the pilot jet
15T front sprocket
(havent changed due to the 50/50 view on this forum)

should i also shim the needle?
acceleration from dead stop is great, i just feel that that it could have more.

I try to upload
Adjusting the Carburetor.pdf
Mikuni Carb Theory.pdf
but the file limit of the forum is to low

You should shim the needle.I bet your running lean in the mid-range. ;) :)