WHAT DO YOU GUYS THINK THE BEST WAY IS TO GET ORE POWER OUT OF MY 400EX?? I HAE A PIPE AND HEADER ON IT WITH A K&N AIRFILTER.
I NEED MORE POWER. ANY IDEAS
I DONT WANT TO BUY A NEW QUAD EITHER I LOVE THE 400EX!

 

Well, your choice of exuast was good. but I would have gone with a powerbomb. Umm, let's see, you can get a piston kit, 12:1 ratio would make it a rocketship. Edelbrock kwiksilver carb, with the piston kit would make your quad a rocketship, and if you do make your compression ratio like 11:1, or higher, make sure to use aviation fuel, or high octane racing gas.

 

my best friend has a fully built 400ex. i did a lot of the work on it and helped him with the research. it's REALLY fast and reliable too. we started out just like you with the exhaust system and a K&N. jetting is a must. go with the Dyno-Jet kit($70) and two sizes up on the pilot jet. then we got a high rev cdi($110)which we only use for sand riding. after we did this stuff it kept up with a piped and geared raptor. my friend wanted to go even faster so a local tech did a great porting job at his flow bench($400). at the same time we did a 440 kit with a JE 11/1 compression piston and Cometic XR400 gaskets($450 presleeved). we also dropped in a mid range cam and had our mechanic put in shortened valve guides, stiffer valve springs, and hardwelded rockers, all from WebCam(about $500). we went to a 16 tooth front sprocket to utilize the power($35). now his bike puts out arround 45-47hp. we run pump gas with no problems. 12/1 compression is to much for a 400ex. it simply puts to much stress on the engine and you have to run a mix of pump and race gas or straight race gas to keep it from "pinging". the power diferance between 11/1 and 12/1 isn't enough to be worth it.

 

45-47 horse power off 11:1. Ha get your numbers straight. Sounds pretty high. Have you dynoed it?

 

Keep's up with a piped Raptor with only jetting & a pipe. Now that must be some pipe!!!!

 

DOES ANYONE ELSE HAVE ANY INFO ON HOW TO GET THE MOST POWER OUT OF MY 400EX. IF A PUT A CRF450 ENGINE IN IT HOW MUCH HP CAN I GET OUT OF THAT?

 

Your friend spent that much $$$$ just to be as fast as a raptor ?? Now thats funny !! There isnt't a pipe built that will itself make your 400ex as fast as a raptor,Ive never been beat by a 400 yet. My advice is to throw your bike into the back of your pickup,fire up the truck and get to 80MPH ,when you get to 80MPH now you are as fast as a raptor [img]i/expressions/face-icon-small-blush.gif[/img]

On a more serious note try going with a 440 kit or nitro.The 400 is a great all around bike but not the fastest all around bike.If you really want speed try the z400 on the yoshi 450 kit,I hear thats a real kick in the azz.


Michael

 

I STILL NEED MORE INFO TO GET MORE POWER!

 

Are you riding it at full throttle? If not why would you need more speed. If you want to go fast the 1st thing i would do is get the suspension set up.

 

You got a 400ex with that much horsepower?! i know of a guy who put a TURBO CHARGER on a 400 and didnt get that much HP!