hey i just bought a 2001 400EX with a K&N filter, Jet kit, gutted stock pipe, Polished DG front bumper, and polished DG nerfs, it hasnt been ridden much b/c it has the original tires with over 3/4 life left!!!! My questions are will an after market pipe give me any advantages over my gutted stock pipe? What do i need to do to be able to hang with and/or beat stock to lightly modded Raptors/LTZ 400s/KFX 400s? What are some good Mods that dont really compromise reliability? Where is a good place to find mods at a good price?

thanks
Ian

 

Well in my case I've done alot of little things that have boosted the heck out of my machine.

here's my 400ex mod list:

1. big gun complete race series exhaust
2. white brothers rev limiter
3. airbox lid with vent kit
4. rejetted carb with 158 main jet
5. jensson racing air scoop shrouds
6. DPR8Z spark plug (wide operating heat ranges prevent fouling from running too cool and pre-ignition from running too hot)
7. uni filter
8. rear itp holeshot 20x11x9 tires
9. renthal handle bars
10. dg nerf bars
11. PRM full body skids
12. PRM baja bumper
13. VP MR1 race fuel (Delivers up to 6% more power over pump gas)
14. took off the e-break because it never worked right and just takes up weight
15. k&n oil filter

That's all I've done and it really helps alot! I can keep up with any of my budy's no problem! I've been clocked at 70mph on the flats next to my budy's bronco and I still had half throttle in fifth...no joke.

Have fun, if you ever need parts cheap and want great service go to www.honda-yamaha.com

Thanks,
Joey Mac

 

By gutting your exhaust your saying you took out the packing?? The packing does serve a purpose and taking it out can actually have an adverse affect on performance. If your gonna do anything to your stock exhaust, I would change the end cap. I dont exactly know how restrictive a stock 400ex end cap is but speaking for my DS, a modified end cap can just about give the same performance as a slip on.

RR01

 

I dont know what I mean by gutted... I didnt do it, it was like that when I got it. The guy just said the pipe was gutted.?.? by looking at it, it appears as if maybe the spark arrester has been removed or something I really dont know that is why I am here to gain more knowledge!
Any input is very much appreciated!

Thanks
-Ian

 

The spark arrester is what usually is the restrictive part on an exhaust. The spark arrester on my DS is totally overkill, along with the two little outlets. The modified version just has a tiny screen going across the endcap, and a bigger outlet. But you should have some type of spark arrester on your quad just incase a DNR stops you, you can get a fine for not having one.

As for future mods, if i was you i would get either a new slip-on exhuast or better yet a full exhaust and then re-jet it. Itll give you good power for the money and make it sound more mean too!! [img]i/expressions/face-icon-small-smile.gif[/img]

 

I bet the packing is still there. He probably just took the baffle out. Buy a slip-on muffler it will help and sound better than that "gutted" thing. I think you can get a slip-on for around $250,or check e-bay. IMO get the white bros e-series,good bang for buck.

 

Macentyre, is your ex geared higher?

 

I would get a full exhaust like a yoshimura or a fmf and maybe the 440 kit. As for keepin up with or beating a ltz400 or kfx. The mods you have will probably at least put you there with a z in stock form. Most of the higher more well known bigger bore kits and pipes don't usually compromise your quads reliabilty. At least not like taking it to a local mechanic and having them do it, even though this is a lot cheaper. I'll probably go the cheap route with my z but I might end up regretting it. It will probably taking a lot more to get in the raptors league but I'd say you're right there with my z right now. Good luck with whatever mods you get.

 

yellowexracer,

nope just stock....seems to be fine and rockin with stock cylinder, gears & components so far.

Mac

 

put a real pipe on it (any),,,,,tune it (jet) properly......gear it the way you want,,,,,,and ride the snot out of it......you will smoke any z400 rider .....that you can outride. If you find a good rider on a raptor,,,,,dont even bother. 400ex is a great bike.
take a look at my 2000