400EX power adders

[SW00P_G]

I am new to the forum and I have a couple questions. I own a 2000 trx400ex and am ready to add a little zip to it. I have a budget of ~$800 to spend. What are your opinions on what to buy. I was planning on a curtis sparks x-4 exhaust and the spark advance key. also adding a 152 main jet and 42 pilot jet. But I thought I would post on here to get ideas for the biggest bang for the buck.

Thanks in advance.

[Pappy]

if you can do the engine work yourself, a 416 kit with a cam and then add in the pipe can be done within your budget!

[04'400ex'er]

The 416 kit would give you great power, but if that is not reasonable then i would buy the Sparks X6, K&N, and a cam. Not a whole lot to do after that besides bigger bore. you could also bump up your compression a little with a new piston.

[Raptor4439]

depends on what kind of riding you want to do, if your just going to be a weekend warrior then it would be good to go with the setup the guys above me talked about. If you plan to go into MX you'll need some race oriented tires (around 200-300 with rims). add that onto the bore kit and cam stuff if you can afford it.

[SW00P_G]

Sounds like alot of good ideas guys. For a little info I am a weekend warrior. Not really going to be doing motocross. What kind of engine work is needed for the 416 kit? Also where could I find pricing and ordering info for the parts you have mentioned??

$800 can get you a drop in cam, .080 over bore on your cylinder and new piston, and a slipon pipe. These add ons will give you exactly what your lookin for..:cool:

[EXDUNER127]

get a full exhaust cause if you dont you will regret it, you will just want a head pipe later on anyway.

Sparks x-4.....489.00
K&N filter.........45.00
advanced key..20.00
take off choke..free
hot cam stg1..129.00

Total......683.00

Then save your money and down the road add a piston!
This will be a good setup for what you are looking for.

[Pappy]

truthfully i'd spend that $800 on suspension:o

[Hotdog]

I agree with Papy, do your suspension first. that will make you faster in the long run

[TCracin440ex]

id get a hi-rev box for your bike they make the world of difference also

[Pappy]

Originally posted by TCracin440ex
id get a hi-rev box for your bike they make the world of difference also

please tell me you dont believe that:p

[Doibugu2]

Originally posted by Pappy
truthfully i'd spend that $800 on suspension:o

I can't believe you and Rico didn't say that first.

Hands down the best investment is shocks. I'm a weekend warrior and love mine.

[shamisc]

Originally posted by SW00P_G
I am new to the forum and I have a couple questions. I own a 2000 trx400ex and am ready to add a little zip to it. I have a budget of ~$800 to spend. What are your opinions on what to buy. I was planning on a curtis sparks x-4 exhaust and the spark advance key. also adding a 152 main jet and 42 pilot jet. But I thought I would post on here to get ideas for the biggest bang for the buck.

Thanks in advance.

I would go with the X-6 if you get a pipe. I've had an X-4 and they SUCK!! Completely stock 400EX's were outrunning me and I had the X-4, all-around cam, K&N, jet kit. Once I bought the X-6, things changed. I was the fastest around untill motor work began! Also, IMO the Sparks advance key is junk! And there is no need for a rev box! Ex's don't make any HP after around 7,000 rpms so why would you want to over rev for no reason?:confused:

I would get the following:
- Sparks X-6
- 11:1 JE stock bore piston
- all-around WhiteBros. cam
- K&N filter and Outerwear
- remove airbox lid
- Get sparks to send the jets with the pipe. Just tell him what mods you have.

[cals400ex]

Originally posted by shamisc
I would go with the X-6 if you get a pipe. I've had an X-4 and they SUCK!! Completely stock 400EX's were outrunning me and I had the X-4, all-around cam, K&N, jet kit. Once I bought the X-6, things changed. I was the fastest around untill motor work began! Also, IMO the Sparks advance key is junk! And there is no need for a rev box! Ex's don't make any HP after around 7,000 rpms so why would you want to over rev for no reason?:confused:

I would get the following:
- Sparks X-6
- 11:1 JE stock bore piston
- all-around WhiteBros. cam
- K&N filter and Outerwear
- remove airbox lid
- Get sparks to send the jets with the pipe. Just tell him what mods you have.


the rev box is very very beneficial on my 406 when drag racing. the extra rpms really help on my bike. on a larger bore, they may not, i don't know. on a stock bike, i wouldn't get one.

my friend has an x-4 and it really woke his bike up. when drag racing it made a good 4-5 bike length gain. unless it was his heavy duty timing chain?? he did that and the pipe at the same time and it woke his bike up over his big gun slip on. i have been told from a few people who installed the heavy duty timing chain that their bikes felt more responsive after the install so i don't know.

[Raptor4439]

Originally posted by cals400ex
the rev box is very very beneficial on my 406 when drag racing. the extra rpms really help on my bike. on a larger bore, they may not, i don't know. on a stock bike, i wouldn't get one.

my friend has an x-4 and it really woke his bike up. when drag racing it made a good 4-5 bike length gain. unless it was his heavy duty timing chain?? he did that and the pipe at the same time and it woke his bike up over his big gun slip on. i have been told from a few people who installed the heavy duty timing chain that their bikes felt more responsive after the install so i don't know.

not tryin to steal ur topic dude but what kind of timing chain did he get? im lookin into buyin one and i dunno who sells em.

[cals400ex]

Originally posted by Raptor4439
not tryin to steal ur topic dude but what kind of timing chain did he get? im lookin into buyin one and i dunno who sells em.


just get the crf 450 dirtbike timing chain. they are well under half the price of a "heavy duty" timing chain by an engine builder and they are the same thing. go to the FAQ forum on this site and there is a topic on the crf timing chain. my friend loves it. i have one but i haven't put it in yet.

[Raptor4439]

Originally posted by cals400ex
just get the crf 450 dirtbike timing chain. they are well under half the price of a "heavy duty" timing chain by an engine builder and they are the same thing. go to the FAQ forum on this site and there is a topic on the crf timing chain. my friend loves it. i have one but i haven't put it in yet.

dude thank you so much! that saved me some cash man, appreciate it! :cool: