Like i said I am way new to this sport. I bought my first bike(2002 400EX) on thursday and the only bike i have ridden before this is a 99 kodiak. Anyways to my questions. What do new handle bars do? are they just lighter? ARe there quiet pipes that perform as well as the others? WHat exactley are 440 kits? hmmmm can't think of anymore right now but i am sure i will have more in time. thanks for all the info you could give me.


Steve

 

Differemt handlebars are lighter more often than not they are stronger and reduce arm pump because they are usually made of different materials than the stockers. A 440 kit is a bigger bore kit for the 400 ex that raises it to a 440cc hence 440ex not sure about any other parts that come on a 440 kit since well I dont have a 440 kit.

 

Steve, another thing with the aftermarket handlebars besides being lighter is that you can pick from dozens of different bend patterns, and this too can also help prevent the arm fatigue that BornBanshee was talking about. You can get bars that are wider, narrower, taller, shorter, etc. For instance, I use Quadracer 250 bend Renthals on my 400 now, which feel fine. A couple of my buddies run Mini bars, CR80, RM80, etc Renthals. This may or may not be a big deal regarding how comfortable you are on the machine.
Regarding a quieter exhaust system that performs very well...I'd look into the White Brothers E-Series. They win magazine shootouts for their performance, quality, and noise levels. You will be able to find better performing systems, but they are mostly race systems that might not be muffled as well, and/or may not have spark arrestors in them for trail-use. White Brothers are very well crafted systems, and aren't much louder than stock...but they ARE louder than stock.
BornBanshee was correct regarding the 40cc displacement increase with the 440 kit. If you want to go with the displacement increase only, then you can get a larger aftermarket piston kit for around $250-$350 for parts alone...plan on another $200 or so for labor if you're having someone do it for you. But the real horsepower increase comes from the "other" add-ons that really cost you. These include cam, valves, porting, carburetors, electrical components, etc. The list really goes on and on. But just because two guys both have 440's, they might be light years apart. Do you want the $300 440cc kit, or do you want the $3,000 440 kit? That's up to you!
My suggestion for a newcomer...start small. First of all...the 400EX is an excellent choice for a machine. Easy to ride, but lots of potential. You'll be suprised how much the stock 400 actually can offer you. If you do decide to go with an exhaust system, you may decide to go with a well known company that you see lots of ads for in all the magazines...White Brothers, FMF, Pro-Circuit, etc. If you need parts for rebuilds, they're readily available at lots of shops everywhere, where if you get a system from more of a specialized company, like LRD, CT, Duncan, etc, you may end up shipping the system back to the supplier for service. Do you want a slip-on muffler only exhaust, or are you going to buy the entire header and muffler system? In many cases, people buy the slip-on muffler only, for a nicer exhaust tone, to save weight, and for a very small horsepower increase. If you go with the aftermarket header as well, you'll save more weight, and get a little more horsepower as well...but the cost also goes up quite a bit.
Get a good quality air filter at the same time. K&N cotton/gauze filters are legendary and a great value, but foam filters like a UNI or Twin-Air offer very similar performance for less money. Also, either pop off the filter lid(if you don't make a habit of running through lots of mud and/or water), or drill some strategic locations for vents if you do water and mud often. Don't forget to rejet the carburetor for the added airflow you'll gain from better intake and exhaust mods like these.
Once you outgrow these performance mods, you'll have a better idea of what direction you want to go with spending bigger dollars. Hope this was helpful info.