400ex upgrade ??

[kingbigs11]

i have a stock 03 400ex. i was wondering if a muffler system and stage 2 hotcam will make a significant difference? can someone please let me know if it will be worth it to make these upgrades

[rdstoner]

just a slip on pipe makes a diffrence. but ya if you get your carb jetted just right for your set up it will make a huge diffrence.

a better suspension makes a bigger difference than an power output mod you can do...if the bike's suspension won't allow you to handle the power that is already there, then why add more power that will not be truly usable anyway

[kingbigs11]

yea..i already had the carb rejetted for the setup. i just need to get the muffler system and hotcam. i just want to make sure its worth it

i really wonldnt get a stage 2 cam unless you have more into it. I agree suspension is way better than having more power. You can go faster on a good suspension/handling and then it opens up the door to performance mods because you can get the power to the ground. A slip on exhaust is fine, you dont need a full system unless you have more into it. Get a better air filter, remove the airbox lid, and jet. Deffinately a noticeable difference. The timing keys work wonders too. I stopped my performance modding if you look at my signature until I get my supension redone, new tires and new handle bars.

[northwest Texas]

speedy is dead on right. I never thought mine was slow until the chassis was dialed in and I could ride so much faster with less effort.

Now to answer your question. Yes, the pipe is worth it. Unless you're doing more to the engine, I'd probably lean towards the Stage 1 cam instead.

But after you do that, it's not cheap but it's so much more fun to have a smooth riding quad that doesn't beat you to death that might be a little slow than to have the fast engine with a death grip on the bars all day long. If you're 18, that's probably fine with you but I'm not and I'd rather have 3 good hours of riding before being worn out than riding a half hour before feeling whipped.

[kingbigs11]

ok. so i guess the plan is to upgrade the suspension, then exhaust, then stage 1 cam. sounds good to me. I was riding today and was jumping for about an hour or so, and i DID notice that the landing was getting kinda hard on my feet and hands. I would love a better suspension. thanks a lot for the advice. if there is anything else you want to add GO FOR IT

[motoboy66]

I have used both a stage 1 and 2 cam in my 2000 400EX. I have a first overbore 11.1 piston in it. I didn't care for the stage 1 cam, and ended upwith a stage 2. I felt that the 400 had enough low end torque and I needed more over rev. The stage 2 rips, but you will need a rev box to realy use it. I hit the stock limiter all the time. As for rev bnoxes, I have had great luck with the Big Gun one. The 2 others I used sucked to start. One was a White Brothers, and I am not sure what the other was. Trial and error, the Big Gun was the best and always starts fine.

I dont like higher rev boxes. I would never put one on my quad. Stage 2 is nice with a bigger bore but stage 1 is great for a stock or smaller overbore.

Originally posted by motoboy66
I As for rev bnoxes, I have had great luck with the Big Gun one. The 2 others I used sucked to start. One was a White Brothers, and I am not sure what the other was. Trial and error, the Big Gun was the best and always starts fine.


that is funny because the big gunn and the wb are the same rev box, just with different stickers on them...

if you are wanting to do suspension first, get a set of 450r front shocks. send them along with your rear to gt thunder for a revalve. also get his rear linkage. there will be a night and day difference. this set up is good for trail riders or even c class racers. once you start getting into the b/a/pro classes, you will need a better suspension set up.

to be honest suspension set up is not about jumps unless you are freestyling or running mx...it is about allowing all 4 wheels to stay planted. the fronts need to keep good solid contact with the ground to keep you pointed in the right direction. the rear needs to be planted to actually get the power to the ground and keep you driving forward...

the rear linkage from gt thunder will almost eliminate the rear end buck on the 400ex(and 450r)...i am sure you have felt that buck...you hit a small jump and all of a sudden the rear end seems to have a mind of it's own and decides it wants to see if the grab bar can meet your helmet...that goes away with the new linkage...

[katch26]

Originally posted by speedyquad
that is funny because the big gunn and the wb are the same rev box, just with different stickers on them...


yep all procom built boxes. I was thinking about this last night on the way home and I guess its just in our nature to want to go fast first and worry about the handling later.....imagine any race car game youve ever owned and were able to build cars up to race, full speed into the turn crash back up (packs caught up) full speed pass everyone into the next turn and repeat

[coryatver]

why did you jet it before puttion on an exhuast? It must run really bad with the stock exhuast on there! You might have to go to an even bigger main when you get an exhuast depending on your air box setup

[kingbigs11]

because i bought it with the carb ****ed up and the mechanic just went ahead and jetted it he said. idk. I dont know to much about them. tryin to learn more. and yes. the stock exhaust is making it run like ****.

[mitchamus]

I would go and get yourself a slip on HMF, UNI foam filter. Remove your lid. Also remove your choke. and jet.
Then look into changing your suspension. Shocks are expensive.

[kingbigs11]

thanks a lot everyone. So will just a slip on help me out a little? One more questions. I dont want a high pitched popcorn muffler. i went on youtube and some of the slip ons sound horrible. I want a nice deep throaty sound. anyone have any suggestions? i was thinking about the hmf ironman

[mitchamus]

Can't go wrong with the HMF... I have the Sport series slip on.

[RaginRedneck]

http://www.exriders.com/vbb/showthread.php?s=&threadid=346007&highlight=exhaust+clip


Here is a link to thread on here that has several exhaust sound clips on 400's should give you a good comparison.

Good luck