best mods for 400ex

[importracer_ky]

i dont want to go with the 440 kit i hear its not good for trail riding.i do want something that would run with a 450.give me some ideas
heres the quad and list of mods already done.
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7989.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7990.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7990.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7992.jpg

Qudtech carbon fiber hood
Hiper wheels frt and back rear has intergraded hubs

itp mxr6 tires
+ 2 +4 g force axle
+2 eyeball a arms
graydon proline nerfs
blingstar iron cross bumper
tag fat bars
terry racing graphics
tom miller motorsports subframe chrome
Baldwin atifade lockhub
pep tripple rate with rezzies shock

big gun cdi
k and n airfilter
tc supertrapp exhaust
new tranny
new clutch

im looking to drop about 500-1000 in the motor

[Wildbrain]

Suspension mods will give you a good bang for your buck

[BigLuke]

Well in the trails you should be able to keep up with a 450 if you can ride. As far as performance a good exhaust, K&N and jet kit will help lots. If your seeking 450 power from a 400 youll need a big bore, cam, carb ect. But I dont perfer the 440. A 416 or 426 can keep up witha 450 if set up right plus there reliable.

[droppedmazda]

a 416 with a cam, jet kit, cdi box, air filter, and pipe will give u plenty of power out of 400ex for decent price. if want real power u can do some port work and get an aftermarket carb. the 426 kit is not the best big bore kit because it leaves the cylinder so thin and i have seen the 426 drop sleeves because its so thin.

[Phillburt57]

I'm suprised no one has said this but pipe the SOB! Get a UNI and re jet all for about 400 bucks. Pretty good bang for the buck. Like everyone else said if you want more power then that you can start tinkering with cams, bore kits and port work.

[droppedmazda]

i did say pipe, jet kit, and filter. i agree with phillburt, uni is a good trail bike filter.

[Bridgewater]

the sparks timing key was a good one for me.
30$ and u can increase your dl down and have a noticeable increase in how snappy ur quad is

[extremeisaac]

steering stabilizer, pipe, twin air.. and suspension..

[importracer_ky]

it has pipe and kn filter.it just seems slugish on take off but top end is good.it was setup for mx racing.i have pics on my other post

[Stoke88]

If its sluggish on the low end try a different gear ratio. That should pick it up a bit.

[importracer_ky]

any gear ratios ideas?

[rob_990]

Originally posted by importracer_ky
it has pipe and kn filter.it just seems slugish on take off but top end is good.it was setup for mx racing.i have pics on my other post

maybe its too rich
or for the gearing try going down one in the front.

[motox92]

Sparks timing key.

[hypersnyper6947]

Originally posted by importracer_ky
any gear ratios ideas?

Drop one tooth on the front sprocket that will help you get off the line faster.

I dont know how much you plan to spend but suspension will make you faster than anything else.

[importracer_ky]

heres the quad and list of mods already done.
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7989.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7990.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7990.jpg
http://i378.photobucket.com/albums/oo223/bigorangecustomscars/HPIM7992.jpg

Qudtech carbon fiber hood
Hiper wheels frt and back rear has intergraded hubs

itp mxr6 tires
+ 2 +4 g force axle
+2 eyeball a arms
graydon proline nerfs
blingstar iron cross bumper
tag fat bars
terry racing graphics
tom miller motorsports subframe chrome
Baldwin atifade lockhub
pep tripple rate with rezzies shock

big gun cdi
k and n airfilter
tc supertrapp exhaust
new tranny
new clutch

im looking to drop about 500-1000 in the motor

[motomadnesam]

cams, head ported, high compression, less restrictive intake, heavier duty valves and springs.

[motomadnesam]

And different front tires.

[importracer_ky]

should i go with stage 1 or stage 2 cam?whats wrong with the front tires?

[motomadnesam]

I couldn't tell you what stage to get (I don't know), but if you are going to do mx, then you should get 20-6-10 front tires. They will not roll as much in the turns. If you are going to do trails then the fronts are fine.

[motomadnesam]

Are you riding mx or trails?

[hypersnyper6947]

get new rear shock, or revalve the stock one

[rob_990]

Originally posted by importracer_ky
should i go with stage 1 or stage 2 cam?whats wrong with the front tires?

stage 2

[cam19aro86]

I've got the stage 1 seems like plenty of low/mid end to me, I like it. I don't ride much at 65mph though.

[importracer_ky]

i use it to trail ride

[zfrank07]

if my 400 is totally stock with the exception of hmf full system and k&n air filter w/o lid. and i add stage 2 hot cams...would i see any gains? i have an 07 ex that is bone stock right now and i want to mod it but keep reliable

[motomadnesam]

Originally posted by importracer_ky
i use it to trail ride

What size are your rear tires?

[importracer_ky]

18"s

[motomadnesam]

If you are going to do mostly trails, then I would look into putting on some 20's for better ground clearance. Also, with larger diameter rear wheels your top speed will increase, but your acceleration may suffer a bit.

[Homerx]

Originally posted by zfrank07
if my 400 is totally stock with the exception of hmf full system and k&n air filter w/o lid. and i add stage 2 hot cams...would i see any gains? i have an 07 ex that is bone stock right now and i want to mod it but keep reliable

Not really you need to add high comp piston, as the HC will lower compression.

[Phillburt57]

Originally posted by Homerx
Not really you need to add high comp piston, as the HC will lower compression.


Where did you hear this?

[hypersnyper6947]

Originally posted by Phillburt57
Where did you hear this?

Hotcams have more lift and duration (valves are open higher and longer) and the more aggressive the cam ie., stage 1,2,3, the more lift and duration which in return looses some of your compression, so with a stock piston which is relatively low compression doing a stage 2 cam could be working backwards because you will lose even more compression. So it is recommended to do at least 11:1 if your doing a stage 2 cam.