New 400EX, Need some INFO on mods
#1
05-24-2007, 10:33 AM
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New 400EX, Need some INFO on mods
Ok so I bought a new 2007 honda 400ex and I was going to buy a HMF sport series full exhaust system plus dynojet jet kit and not sure if I should get a k&n filter or UNI, just wondering what other mods I should get to help it performace wise or any other tunning advise you guys have. Reason being I want to be a little faster cause my friend has a YZF 450, just want to be a little faster then stock. thanks
#2
05-24-2007, 11:18 AM
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#3
05-24-2007, 11:25 AM
New 400EX, Need some INFO on mods
HMF is a good choice,it will help out on bottom and mid range.K&N is fine as long as you use a pre-filter(you might get the jet you need from HMF if you ask).I would invest in a rev-box,you will tell a lot of difference with these three mods.If you get the jet you need from HMF you won't need the dyno jet kit,so the money saved will pay for the rev-box.Later Marvin
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05-24-2007, 11:32 AM
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#5
05-24-2007, 11:35 AM
New 400EX, Need some INFO on mods
<div class="FTQUOTE"><begin quote>Originally posted by: Scootergptx
Use a air box lid filter like K&N or this. Along with the other air filter (K&N or Uni).</end quote></div>
Agreed. I wouldn't do anything else besides your plans (pipe/filter/rejet) and the lid, you will get nice gains just out of that, and won't effect reliability.
If you do get a K&N or any other high flow lid, make sure to rejet AFTER you put on the lid.
Use a air box lid filter like K&N or this. Along with the other air filter (K&N or Uni).</end quote></div>
Agreed. I wouldn't do anything else besides your plans (pipe/filter/rejet) and the lid, you will get nice gains just out of that, and won't effect reliability.
If you do get a K&N or any other high flow lid, make sure to rejet AFTER you put on the lid.
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05-24-2007, 12:50 PM
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New 400EX, Need some INFO on mods
Ok cool thanks guys, I am going to ask hmf before I order if I can get the jet from them, and difference between dyno jet or any other jet company performace wise or are all jets bassically made the same just different sizes. Just one more question pretaining to the air filter is K&N better then UNI or are they really the same cause I heard the K&N lets in more crap so people were saying go with a UNI foam filter to filter more of the small particals out. Thanks again guys really helped me a lot in my decisions
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05-24-2007, 02:13 PM
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#8
05-24-2007, 02:51 PM
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New 400EX, Need some INFO on mods
<div class="FTQUOTE"><begin quote>Originally posted by: Martianman
HMF is a good choice,it will help out on bottom and mid range.K&N is fine as long as you use a pre-filter(you might get the jet you need from HMF if you ask).I would invest in a rev-box,you will tell a lot of difference with these three mods.If you get the jet you need from HMF you won't need the dyno jet kit,so the money saved will pay for the rev-box.Later Marvin</end quote></div>
Will a rev-box really make a difference? I guess I'm not sure how they work but I thought they just move your limiter up a little. I may not know what i'm looking for but I've never noticed hitting a limit on my 'EX and I know i've rapped it out enough that my hp was dropping. Will it make any hp in the rpm range you gain from a box?
HMF is a good choice,it will help out on bottom and mid range.K&N is fine as long as you use a pre-filter(you might get the jet you need from HMF if you ask).I would invest in a rev-box,you will tell a lot of difference with these three mods.If you get the jet you need from HMF you won't need the dyno jet kit,so the money saved will pay for the rev-box.Later Marvin</end quote></div>
Will a rev-box really make a difference? I guess I'm not sure how they work but I thought they just move your limiter up a little. I may not know what i'm looking for but I've never noticed hitting a limit on my 'EX and I know i've rapped it out enough that my hp was dropping. Will it make any hp in the rpm range you gain from a box?
#9
05-24-2007, 03:28 PM
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New 400EX, Need some INFO on mods
Ok I found that HMF sells carb jets seperate from there exhausts just wondering if this is a good deal or if I should stear away from it and get a different aftermarket filter and jets. https://hmfengineering.com/view_prod...roduct_id=4173
#10
06-02-2007, 01:18 AM
New 400EX, Need some INFO on mods
The best way to get good performance out of ur 400ex is do for starts is get a pipe jets and an air filter. Depending on what u r willing to spend there are many option on a 400 ex. I hav a very strong running 400ex. I have very good low to mid range. I installed a HMF sport seried slip on a dynojet kit k&n air filter a hotcams stage 2 and a weisco 11:1 piston. This alltogether was 1000. Anyone can install the air filter and pipe that is simple. But if u want someone to install ur jets cam and piston it will run u about 500 dollars, that is at a 70 dollar shop rate. I was very pleased with my 400 performance but dont make the mistake i did of thinking it will compete with 450... i can drive and at a senctioned drag race i raced against my bddy he had a 450r with hmf full lid off jetted and cam and i took him off the line big time but mainly bc i can take off better but he beat me in drag. also i tt raced it and i got the holeshot in the 400 class. You cant get a much better setup for a 400ex right now... as far as the K&N if u arent lasy u wont run into problems if u keep up maintence. My dad just bought an 07 450r and my freind has an 07 yfz 450 i can beat both but not by much. I hav no trouble keeping up with them all day long no probs. This quad has great low to mid range. This will only put u at about 30-31 horse range i had mine dyno ran at 30.8 horse and if you want top speed the best thing to do for starts is go down one tooth or in the back.... dont go down to many or u wont have enoguh power to turn if you dont do enough mods.... i hope this post helped u