Im looking to mod my kfx400 03. im looking at what i can do without vioding my warrenty, i can do everything but internal stuff to the engein, bore, cams ect........ i was looking at the Ti4 full pipe and K&N air filter, but what is hte difference in the new air box or is it just the lid that has holes? also a jet hit.... what else show i get to make it more punchy

 

Also what are some good stores online that i can order from?

 

Speaking from my experience only. I wish I would not have waisted my money on the K&N filter. If your looking to upgrade your filter go with a traditional foam type. They are cheaper, easier to maintain and in some cases they even breath better. As for your airbox lid just remove it. Cutting holes in it is permanent if you remove it, you can re-install it should you ever decide to ride through a river. I have rode for hours in the rain and mud with the airbox lid removed without any problems, just make sure your drain plug is removed. After pipe and airbox mod the rejet kit will be absolutely necessary. You will quickly learn that these three mods alone wont be enough. If your anything like me you will end up spending more to pep your quad up and some of those mods will negate carb re-jetting and air filter mods. If that's so don't waist your money. Get a good pipe upgrade your carb and CDI and you will be extremely happy. Any other worthwhile mod will be internal.

I recently rode after installing the edelbrock quicksilver carb and dyna fs ignition and I could not have been more impressed. The bike has substantially more power throughout the whole powerband but the biggest difference was at the bottom. If you can believe it the KFX is even more torquey now than stock. Its also nice not having to deal with the rev limiter kicking in way to early like it used to. I have heard people say that it is pointless to increase the rev limit without other mods, I can not disagree more. The motor as is has a little more to offer after 9100 rpm and it just feels better having that extra breathing room.

 

Hey sandmudandhills whats the top speed of your kfx according to your speedometer?

 

Im not sure on the top speed but the fastest I have had it is 56 mph. I imagine I could get it up to 60 if I tried hard enough.