400ex weaknesses

[redrabbit]

can anyone tell me some common weaknesses for my 2000 400ex? thanks

just the stock front shocks wont take a huge beating they are rather soft and bouncy. other than that its basically a bullet proof machine

[katch26]

its got alot of weaknesses IMO. YES the motor IS bulletproof but the design is antiquated. The frames crack (most sport quads will) the carb is weak. The shock are such a bad design, its 2008 and the still don't come with piggybacks or compression/ rebound adjustments. If youre buying new it would be hard (for me anyways) to cough up the cash on a 400x when for around the same money you could get soooooo many more standard features on something else.

on the plus side parts are literally everywhere and if youre buying used they can be had for next to nothing. If youre new to quads its a great machine to learn the proper upkeep on. Don't get me wrong I love my 400ex and for me it fits MY needs perfectly as I already have a maintenance queen lol.


oh and I hate the one peice subframe. As easily as these things wheelie it would be nice to be able to replace the rear grab bar when it get bent or worn down

[Punkmaster Flex]

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[miller821]

Heavy jumping will cause a lot of damage.. Shocks aren't truly capable and will cause shock mounts to crack/break.... A-arms can sometimes rip where the shock mounts to them.... Speaking from experience, it's a nice trail quad.. But I'll leave any track time to my suzuki. (Not saying the 400 isn't capable of any jumps, just you need to re-enforce for safety. IMO)

Reinforce as in? New arms, and shocks? Whats some good arms that are not too expensive... Maybe some +1's or just normal ones. For shocks I think I'll go the 450r route.

[HondaRaceReady]

I saw on the durablue axle website, 400ex's have limited swingarm travel.

[miller821]

If you doing heavy jumping then yes I would suggest new A-Arms and shocks, and also maybe some gussets... If you just doing to do trails I'd keep it the way it is for now.

[BlasterEaten250]

How big of jumps will you be doing?

I pretty much ride all around. alot of open and tight trails. SOme trails I never get out of 2nd. Then I also got some jumps and a track like setup. Would you recommend like some houser +1 A arms? Shock wise should I go with a 450r setup or get some aftermarket ones? I thought about goin +2 but I would have problems in some of those trails.

[Wheelie]

The Houser +1's with an upgraded shock is money well spent. Killer setup.

Would houser +1's and 450 shocks be a nice setup?

[lilyamaharacer4]

Yes, once you get the shocks valved for the 400.

I always wondered how much that cost to get them revalved.. If you run +1's should you get longer axle too?

[miller821]

Originally posted by SuicideMFNdoors
I always wondered how much that cost to get them revalved.. If you run +1's should you get longer axle too?

I think C&D does it.. If not I'm pretty sure one of the site sponsors does, so just check around at some prices... They're pretty reasonable.

I'll check em out.. i heard it aint too bad.. So if you get +1 arms should you get a +2 axle?

[powermadd400ex]

its not a neccsity, im running +2 arms and im using the stock axle and it is still handles great.

[Balaz_73*00]

weak points-frame, if your gonna be doing any type of hard riding or jumping i would gusset it up. I cracked my 400 frame only a few months after getting my quad the second time i was at the track, and not just in one spot. I had like 5 differents spots with cracks after my third moto of the season. pretty scary crap if u ask me

[sc400ex_rider]

if you race it you might have frame probs but just trail riding you will have very little. the only real issue is the swingarm pivot bolt can rust and seize in place. some do some dont. i have a 02 i bought new and had to replace nothing due to failure. its modded too, its reliability is the best in the buisness. if you buy used and its neglected you might have probs also. its not notorious for probs like almost any other quad esp 450's.

[outlaw319]

I've always been a Honda man because of the limited problems and durability! I love my 400 but I've noticed a few common flaws with the engine....#1 being a weak cam chain,#2 i noticed quite a few people replacing the cam chain tensioners due to failure.#3 valve cover bolts stripping out easily,#4 the cooling issues with the motor. But all of those can be easily fixed and pose no major problems if caught early on. Sure still beats riding any other brand:D

[sc400ex_rider]

i think alot of the cam chain tensioner failure is because people dont know how to retract and set them. they just pull them out and bolt them back on destroying them. im still on my original one. the timing chains go bad but thats after many seasons of racing with a heavily modded engine. the bolts strip out because people over torque them. the valve cover bolts torque is only like 10 ft lbs. if you mod the motor they will run hot, i put a little fan on mine to cure that.

[Yippie-Ki-Yay]

Fire.

[mx8]

Pepole who are breaking there frames must have a bad shock setup or something. Stock shocks are not setup for racing. I raced for two seasons on a 1999 400ex with PEP ZPS shocks, laeger +2 a arms, 1 1/4 swingarm. And never broke or cracked any part of the frame. That was 16 fair races, 4 GNC nationals, and over 20 dist 11 races each season all motocross. Just my 2cents but buy shocks that are made for the 400ex and are set up for your riding style, and if you have the extra money buy good shocks. Works shocks are good for TRAIL RIDING!!!! PEP,AXIS, and a few other top name shocks are setup for hard riding and racing.

[mx8]

Pepole who are breaking there frames must have a bad shock setup or something. Stock shocks are not setup for racing. I raced for two seasons on a 1999 400ex with PEP ZPS shocks, laeger +2 a arms, 1 1/4 swingarm. And never broke or cracked any part of the frame. That was 16 fair races, 4 GNC nationals, and over 20 dist 11 races each season all motocross. Just my 2cents but buy shocks that are made for the 400ex and are set up for your riding style, and if you have the extra money buy good shocks. Works shocks are good for TRAIL RIDING!!!! PEP,AXIS, and a few other top name shocks are setup for hard riding and racing.

i really dont know how you break the frames because I launch my quad and beat on it so hard and nothing has broken. 4th gear regularly pinned over whoops just slamming into them sometimes 5th gear. Jumping is mostly 3rd gear. My quad has been front flipped end over end top of 3rd gear and rolled off the side of small cliff and nothing at all has broken. The only things broken were user error stripping 2 bolts the long oil filter cover bolt and one the torque wrench was set 2lbs higher on accident and snapped the bolt for the right side crankcase and cracking valve caps. 450r shocks do not need to be revalved to ride good. they ride just as good as the 400ex rear shock and the stock honda shocks that are fully adjustable will ride pretty nice if you spend time with them tuning them. if you ride hot areas and ride hard for a long time will will notice some heat fade were you start losing power but a higher weight oil and synthetic can help that out a lot.

[Ryan'07400ex]

Doesn't start well in cold weather, but i guess all atvs are like that to some extent (cept maybe fuel injected one.)

so you dont have to get your 450's revalved.. is there much of a difference if you do get them revalved?

Originally posted by SuicideMFNdoors
so you dont have to get your 450's revalved.. is there much of a difference if you do get them revalved?

no, you do not need to get them revalved. you can make all 3 shocks work amazing and on par with aftermarket but that isnt neccesary. I have bottomed out my 450r shocks tons of times and the preload isnt all the way off and compression and rebound are turned up some so they arent stiff like people make them out to be

[2muchquad]

bolt'em on and go,you can fine tune the adjustments..