Help! Pointers on 400EX's Needed Please!

[Z4J]

Hey all I know this is a beat down, worn out subject, but I’m hoping for pointers on making a 400EX somewhat competitive for a few MI hare scramble races. I’ve always ridden YFZ’s, then retired, had a baby and thought I was done. A buddy of mine picked up a couple old EX’s that we’re looking to restore for a winter project. Truthfully, I don’t know much about Hondas. I’m hoping a few of you can chime in with mod’s/adjustments that you feel are well worth it and ones to avoid. I know I’m not going to be world class, but something fairly competitive would be all I could hope for. I’d like to search, but right now I have a 7 day old (our first) and that’s 90% of my time and the other 9% is attempting to sleep. Here’s what I do with my other 1%. Try to give me a hand please. Thanks.
Weak cam chains?
Gussets?
Ele.?
Bore kits?
Head bolts?
Suspension mod's?
Known problems?
Quick mod's?
Most have mod's
Etc.

[Ruby Soho]

ill try and answer some questions.

the 400 is pretty rock solid.. but heres what goes wrong if not done right when you mod your motor.

the cam chains do stretch, not all of them though (for example.. i run a stock cam chain in a 440.. its been 2 years and no stretch). solution? crf450 cam chain.

the head studs stretch usually with bigger bores, or more compression. its always safe to go with HD studs in a big bore.

the most common big bore is the 416, makes good power, if you build it right it will beat your average 440. and still be more reliable

theres some common spots to gusset the frame but if your not MX'ing i don't think you'll need to.

suspension is always a good upgrade, a common mod (i did it aswell) is the 450r shock upgrade. the trx450r front shocks are a million times better than the stock 400ex shocks. and after you get them revalved/resprung there competitive with elkas etc..

few must haves would be nerf bars, handle bars (so your comfortable), decent tires, skids etc.. for hairscrambles.

quick mods.. some that i did were the 450r pegs, i doubled them up on each side and wow, what a nice set up for so cheap. (i have them for sale if your interested). theres plenty of others but ill let someone else touch more on that

[dirtdigger71]

Good advice ruby soho! a set of air scoops to put more air flow to the engine is a plus. a stage 1 hotcam gives them a little more grunt and a steering stabilizer is worth its weight in gold.....next!

[Brauap]

Moneys no issue?

Hipers
Curtis Sparks Exhaust
Flexx Bars
416 bore kit
Razr2 tires
Percision Stabilizer
+1/+0 Houser A-arms
+1 House Swing Arm
Axis/Fox Floats (shocks)
Hot Cams stg. 2 cam
Tire Balls
-2/+1 PRM axle

ect.. but I have a feeling money is an issue due to your child so...

Razr2 tires
CNC Stabilizer
reworked 450R shocks
reworked OEM rear shock
guards (belly, swing arm, possibly a-arms)
and possibly a nice bumper and nerf bars

thats really all you "need" to start racing..

STAY AWAY FROM:

Tusk Nerf Bars
DG Nerf Bars
K&N (if in a dusty enverment)
DG exhaust
Cobra exhaust
this is all I could think of as of now

Good Names:

HMF
AC
PRO ARMOR
PRM
HIPER
MAXXIS
ITP
KENDA
UNI
DOUGLAS (except from their .??? wheels)
ect.

[Z4J]

Great information! Thanks you all very much and please keep it coming. A very big help that I appreciated very much!

[2muchquad]

congrats on the new kid..i know free time will be hard to come by for a while,kids are a big adjustment.

Dont worry about trying to make it run like your old yfz,dont keep throwing money at it for minimal returns.If you just want to do some gncc races,a cam,piston and a good slip on will help,like stated earlier get the crf cam chain,this is a must do imo.Some a arms and suspension and other small details,it doesnt take much to get the 400ex ready to go.heres a little secret with the 400ex,while its not the fastest machine on the market,its good at doing whatever the rider/owner wants to do,be it harescrambles/trails/mx,hillclimbing:D it doesnt matter.It just goes along with a journeymans approach to the task at hand.It wont woo you with performance or rip the bars out of your hands but it can move out with a purpose to the rider that can use the gearbox and clutch efficiently.Yeah they dont get a lot of respect since the 450s came out but when that 450 breaks,the 400 that just sits in the back of the garage is ready to go when called upon.

[Brauap]

Here are some other threads that could possibly provide you with some useful information:

1 (http://www.exriders.com/vbb/showthread.php?s=&threadid=372566&highlight=%2AXC%2A)

2 (http://www.exriders.com/vbb/showthread.php?s=&threadid=371230&highlight=%2AXC%2A)

3 (http://www.exriders.com/vbb/showthread.php?s=&threadid=349366&highlight=%2AXC%2A)

4 (http://www.exriders.com/vbb/showthread.php?s=&threadid=345645&highlight=%2AXC%2A)

5 (http://www.exriders.com/vbb/showthread.php?s=&threadid=341094&highlight=%2AXC%2A)

6 (http://www.exriders.com/vbb/showthread.php?s=&threadid=337938&highlight=%2AXC%2A)

7 (http://www.exriders.com/vbb/showthread.php?s=&threadid=373904&highlight=%2AXC%2A)

8 (http://www.exriders.com/vbb/showthread.php?s=&threadid=343628&highlight=Post+Your)

Hope I helped!!

[Z4J]

Awsome!

[rcatvrider]

Originally posted by 2muchquad
congrats on the new kid..i know free time will be hard to come by for a while,kids are a big adjustment.

Dont worry about trying to make it run like your old yfz,dont keep throwing money at it for minimal returns.If you just want to do some gncc races,a cam,piston and a good slip on will help,like stated earlier get the crf cam chain,this is a must do imo.Some a arms and suspension and other small details,it doesnt take much to get the 400ex ready to go.heres a little secret with the 400ex,while its not the fastest machine on the market,its good at doing whatever the rider/owner wants to do,be it harescrambles/trails/mx,hillclimbing:D it doesnt matter.It just goes along with a journeymans approach to the task at hand.It wont woo you with performance or rip the bars out of your hands but it can move out with a purpose to the rider that can use the gearbox and clutch efficiently.Yeah they dont get a lot of respect since the 450s came out but when that 450 breaks,the 400 that just sits in the back of the garage is ready to go when called upon.
I agree with all of that. For harescrambles I don't think you need the most powerful machine possible. Nice suspension, some bolt-ons and a good rider is more important.

[Z4J]

Hey all. I just wanted to say "thank you" again to all that helped. Much more information that I thought I was going to get. I also appreciate the understanding and giving me a hand with my lack of time right now. When I get things done, I'll post a few pics. Have a great Christmas!

[Brauap]

Originally posted by Z4J
Have a great Christmas!

You too, bud! ;)