Hi all, I'm wondering what to buy first to make the bike more attractive and to get more performance. I heard about K&N air filters and a new pipe. Is it the best suggestions? What brand is the best for new pipes/exhaust?

ps: I'm new to all this, so speak so I can understand please! ;-)

 

Dirtwheels or ATV action did a complete article on 400EX mods last month. The only ones that seemed worth the dough was a K&N filter and a jet kit.

All of the pipes they tested, and they tested many, gave minimal gains for maximum dollars.

 

I've had mine rejetted, airbox modified(6 1" vents), K&N, & Supertrapp with 12 disks. The power gain was substantial, so much so that I shreded the stock tires the first ride out with the new stuff and had to switch to Holeshots.

 

SO WITCH WOULD BE THE BEST MOD.. FOR THE BIKE

MINES A 2001 ALSO HAVEN'T STARTED ON THE MODS YET EXCEPT NEW PLASTICS

-01-H-400EX--WAS YELLOW ABOUT TO BE ZEST ORANGE--YELLOW & DARK BLUE
-98-Y-BIGBEAR-4WD-WENCH
-99-Y-TIMBERWOLF-NO RACK-WENCH

 

$for$ the 440 kit plane and simple its reliable and cheap. keep it stock and big bore it. WERE TALKING SLEEPER, just change air filter take off lid and rejett and take the potato out of the silencer then go up one tooth on your front sprocket. you will look stock and smoke most anybody off the line, and have funnnnnnnn

 

I'm not sure exactly what the "lid" is. Is it the smal plastic thing attached under the airbox?

And what you mean by rejetted? I'm not common with the language. Does that mean to add a new jet kit? what is a jet kit?

thanks

 

Also, RAZR13, what do you mean by "big bore it" ? Is a "big bore" some kind of mod? If so, can you give me a brand or a name of who does that?

 

"Lid" = Airbox lid..if you take it off you get better performance as you get more air. Downside is the filter get dirty/wet much faster.

"Big Bore" = Make the engine bore bigger by machining the cyclinder and putting in a bigger piston. This makes it a 440cc machine IE 440EX.

Mac

 

If you don't want to spend a lot of money, airbox and carb mode are cheap and a good source of power. You can drill holes in the airbox lid and put a tube or pipe in the hole to direct water away from the filter if you go in water. you can also re-jet( putting larger jets in the carb) and you will get a good increase in power. more air and gas will give you more power. next is an exhaust mod, to help the extra gases get out faster.