need some help with my quad

[jdrolls]

ok i want to make my 2001 400ex into a 416 or a 440 but i dont no what i have to buy? i do alot of trail riding and i just wanted to have some more power. The only mod i have done with the engine is K+N air filter. If you guys can help me out that would be great.

[bwamos]

If you jsut trail ride and only have an K&N filter I'd reccomend the following.

Full system pipe. (Header and Silencer).
All-around grind CAM.
Ignition advance key?

After that suspension. Smoother = Faster.

I wouldn't really get into boring out the motor. The stock bore has plenty of power for the trails with the right bolt on mods.

[sonof_perdition]

I agree mostly. I have read that a aftermarket header on a stock 400 will cause the quad to lose HP.

Shocks First

Slip-on exhaust, modified airbox and rejet Second

After that maybe a cam or avanced timing key (but not both together)

400ex is pretty awesome on the trails out of the box.

If you want more power... sell your 400, buy a bigger CC quad and take the money you were going to use on mods and use it on your new quad.

the setup I have is great for the woods! Its all I need to be fast, sure you can get more power but in woods its more talents and manuevers that make you what you are. You can do without a cam and piston but if you do get a stage 1 hotcam and a higher compression piston you will have tons of power with a slip on and the K&N. It all works together. Depends on how agressive you are or what kind of trails you ride in would make 1 thing or another worth while. The only other thing I plan on doing with my 400ex is 450r fronts and getting all 3 shocks revalved and resprung.

[jdrolls]

thanks for all the info guys.i have a couple of more questions

1. what is a Ignition advance key and what does it do and what is a good one to get?

2. How is the big gun evo X exhaust

3. should i go 1 down in the front for the sproket

4. what size jets should i get. (i dont no anything about jetting)

thanks again

[Honda10]

The first thing that I would do is get suspentioncuase without suspention you wouldent be able to go fast. Then I would probly get and HMF slip, K&N, and open airbox and jet it.

[kawiefan]

Originally posted by jdrolls
thanks for all the info guys.i have a couple of more questions

1. what is a Ignition advance key and what does it do and what is a good one to get?

2. How is the big gun evo X exhaust

3. should i go 1 down in the front for the sproket

4. what size jets should i get. (i dont no anything about jetting)

thanks again
idk about the big gun but i know the hmf slip on is a good pipe. if you feel you need some more grunt on the trails then yes go a tooth down.

the jetting depends upon which pipe you get and weather you leave the airbox lid on or off. i think the stock jetting on the ex is a 148 main. you probably at least would have to go up to a 155 to start. and possibly go up a size on the pilot

[250exkid]

do i have to take the whole motor out to put in a stage 1 cam? and what are the gains?

[sonof_perdition]

I don't know everything about this subject so the people who do please correct me if I am wrong.

From what I understand, an ignition advance key increases the ingition time of your spark plug. This alows you to run more efficient fuel ignitions. I hear curtis sparks makes one for about $20. I think its a 6 degree timing key.

I also don't know much about the big gun exhaust. I do know that HMF is a popular brand and is known throughout this forum a a good quality performer. I personally run a FMF Powercore 4 but only because I got a great deal on one. I like it though.

I went one tine down on my front sproket. I lost a bit of speed in the top end but the low end is a torqe monster. I run primarily in the sand and I would deffinetly recomend it there.

Jetting is kinda give and take. Usually, the exhaust manufacturer has recommendations according to what other mods you are running. Thats how I started mine and then I tweaked it from there according to what my plug and exhaust color looked like.

If all your riding is in the woods you don't have to do much. Like I said the 400ex is King in the trails. I ride with Banshee's, raptor 700's, yfz 450's, 480r's and 450r's and none of them can touch me on the trails. I usually have to stop and wait for the group to catch up with my if i am leading. Mostly it depends on the rider.

There is a ton of great info on this forum if you have the patience and time to research. Also, don't just rely on our answers to your questions. Read other peoples questions and answers to unrelated topics. I learned quite abit that way. In fact, I am not too machanically inclined and I have impressed my mechanic buddy's with info I have learned here.



Long winded, huh?