Air filter, air filter box.
 

Hello. Got little problem with air filter box, air filter, and rich fuel mixture. Any tips how can i improve air filter box to get more fresh air? I got this air filter with bike. Is that filter not small for 250cc ( big bored to 300cc+). My air\fuel mixture screw was unscrewed 4 times. but i still getting rich mixture. :doh:

http://pics.lt/image.php?di=B1C7

http://pics.lt/image.php?di=SMAZ

http://pics.lt/image.php?di=XWBK

http://pics.lt/image.php?di=H43B

http://pics.lt/image.php?di=D0UY

There`s nothing wrong with that style of air box; it should feed your engine just fine. BTW, the more you unscrew the pilot mixture screw, the richer it becomes.

What is the actual symptom? Does it bog when you open the throttle? Do you need to turn the pilot mixture screw out four turns just to make it run?

When i open the throttle quick it throws BLACK smokes plus when it get warmer it doesnt want to work properly. My spark plug like coal.

What happens if you have the pilot mixture screw turned out just 1/2 turn? Where is the clip on the jet needle?

big bores generally need leaner jetting to compensate for increased suction. try screwing in the idle screw and raising the clip on the needle