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Discussion Starter #1
Hi everyone i am new and posted what i have in the intro thread. I have had my 02 400ex for about 6 months now and feel i have gotten to know the beast. I feel you must get to know your machine before you know what to modify on it. I have been tossing around the idea of either widening it or going with a bore kit. I have looked into the 440 bore kits but found a few stories about them being not as reliable and overheating. What about the 426 kit? I found a 440 kit with wiseco piston 11:1, all gaskets, sleeve, stage 2 hotcam for a good price. I was told i will need to rejet the carb and remove the airbox lid.

Any more info to help me decide would be appreciated. Links to kits and such would be even better. I would also like a list of what i will need if anyone could help.

this is what i think

440 bore kit with cam
jets
 

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I think it's kinda risky, but you'll feel alot more throttle. And before I tore into the motor, I'd get a nice suspension set-up. Not neccessarily making it alot wider, but aftermarket suspension custom to your riding, weight, and stuff will make the quad ride so much smoother. Even the pros would say to get suspension before engine mods. (Even though they have the cash to get it anyway. lol)
 

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Discussion Starter #3
Thats what i was thinking. I was thinking wider and maybe different shocks? What brand won't break me? I just use the quad for running around and "trail" riding not racing. I just would like it wider to make it more stable. At higher speeds on gravel it tends to get a fish tail going.
 

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Works shocks.

Elka's are like 1 of the best, but might cost too much.

I also heard good things about HLS shocks.
 

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Ebay some front 450r stock shocks and have them revalved they will give you a good ride for a good price keep rear shock and revalve it and you will like it for a fraction of the price of a new set. i have a set of revalve 450r shocks to put on mine just have not put them on yet. And start with a good exhaust. I like CURTIS SPARKS or LRD. full systems HMF is also another good one. K&N air filter and then jet the carb that will liven the bike up. And if yo want to build it go with a 416 or 426. my buddies have had a few and they r fast and still reliable. Google 400ex modifications and you will find some good sites.
 

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I also thought about telling him to get them revalved.....But if you ride in dusty dirty conditions, I'd get a UNI instead. K&N's tend to let a lil more dirt in than the UNI's do.
 

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Discussion Starter #7
It has a different airfilter but its a different type made by K&N. Its a foam and not cotton under mesh. I thought about the 450 shocks because i have seen alot of good deals on ebay for them. I like the curtis sparks exhuast too. How about this combo. 450 shocks front and stock rear revalved for my 300 lbs butt and curtis sparks exhuast with uni filter/w outerwears and retted carb. Would a better coil help any?
 

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Discussion Starter #9
Ok i just scored some works triple rate shocks for the front for cheaper then i could get new or even used 450r shocks. now for a newb question, where do i get my shocks revalved for my big butt? another question is how hard is it to jet my own 400ex if i get a pipe? i will get a manul for it too but what company makes a good one? Thanks in advance guys.
 

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GT Thunder revalves shocks. Really good place to go with.
 

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What company makes a good what? Pipe?
 

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The best manuals I have used r the oem manuals at honda but Clymer makes a nice one as well I have both. Check your local shop and they may recommend alot of places or dirt wheels mag has adds in back.
 
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