instead of taking off my airbox lid and having to rejet, can i take off 3 clamps holding down the airbox lid and leave one sitting there, then, as the RPM goes up the lid lifts up 1.5cm on one side, that is about equivalent (in extra ariflow) to lifting up the entire lid by about 0.15" or 3.5mm, it doesnt make a huge difference in sound like it does when i take it off completely.

 

Sounds like you took the course on backyard engineering... believe me I'm all for crazy ideas, but in the end jetting is the right thing to do. Get the jets and learn how to do it yourself... they are cheap and its really one of the things that you can do yourself even if your not a grease monkey. Its not rocket science... thats why all us meatheads are into it. One more thing... ALWAYS follow the most important rule... if you get frustrated and things are not going right... grab the nearest cresent hammer, and beat the **** out of it... then get on the forums and ask how to fix it.[img]i/expressions/face-icon-small-happy.gif[/img]

Seriously though... do a search for "jetting" and you will see tons of threads on how to do it.

 

Another note, are you running the stock carb? If so, it really does seem to work better with the air box lid on. If you have an aftermarket, take that thing off and re-jet. Big difference to be had at that point....

 

i still have the stock carb, and when i take the airbox lid off i cant feel it pull any harder, and it doesnt do wheelie easier either, it just changes the sound.

so if taking off the airbox lid does very little good for power gains, i wont do it. And there's probly no jet kits for ds250, only mod out there is an axle and nerfs

however, i found out today that the bolt that holds my rear shock was loose b/c the nut fell off, (dangerous) the only way i can fix it is if i take the end pipe off so i only have the header pipe left so i can actually get near that bolt. i did that but i cant find a nut to replace the missing one so i'll leave the pipe off until i find a new nut. I started the engine and it was extremely loud [img]i/expressions/face-icon-small-happy.gif[/img] at about 3000rpm (im guessing) it is about as loud as a fully revved out crf/kx/yz/rm 450. i'm not sure if i get much power from that, cuz i havent driven it cuz that would scare the hell out of livestock and give them heart attacks

is there any aftermarkte parts i can get for my ds250, other than an axle, this is what i want for my ds250

-wheel spacers or wider axle and new a arms to make it wider, currently its 40.5 inches wide
-exhaust, end pipe and possibly header, (is header harder to install) a slip on end pipe is simple to install (preferably FMF or WB)
-new susp and a arms maybe
-bore it out, in my other topic, prairie 650 and ds250, they have same size stroke, so maybe i could bore out my ds250 from 71mm to 82mm and put a wiseco piston in it that was meant for a bored out prairie650 (i have no experience in this subject)