2013 Honda 400ex

rich1

Member
Jan 6, 2014
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N.C./RTP
Picked up the new Honda 400 X on Sat .:)
Im going to do a mild build starting with the front shocks. The 450 R front shocks will be a good upgrade, and like the rear shock will be re-valved by Works . The front Bumper and Nerf bars will be Alba , of course ! A Folding shift lever will be by Moose, again. The skid plate /arms will be by PRM. The motor work / parts will be from a from friend at Honda HRC . ;) It will be plenty fast for me and a lot less than a 450 R too.:D
2013 Honda 400ex 002.JPG 2013 Honda 400ex 006.JPG 2013 Honda 400ex 005.JPG
 
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Sweet! I can't wait for someone to buy one from the dealership so that I can test drive it before handing it over lol. If you need any info, specs, part numbers, etc., let me know. I have the hookup.

EDIT: sh*t, I AM the hookup lol
 
The Honda 450 shocks came today. Very minor mods done to make them fit. OMG ! The difference is night and day from the po-go stick stock ones. Some said they rode too hard in the front, if you weigh 150 or less . I weigh 175 and they are perfect for me !
Honda 450 shocks 001.JPG
 
What is going on here ?:confused: The 400x is an air cooled motor with an oil cooler. However the cooler is mounted near the bottom of the gas tank. There seems to be very little air getting to it at lower speeds, trailriding mostly.
. So I made a ram air duct to direct air straight to the cooler. Checking the oil temp at the cooler with a temp sensor it shows about 5 degrees lower. Motor is still breaking in so no high speed testing done yet.
Honda 450 shocks 002.JPG Honda 450 shocks 003.JPG
 
This was a common mod on the earlier ones. Seems the 400ex didn't like to get hot and with oil cooler it helped allot..
 
This was a common mod on the earlier ones. Seems the 400ex didn't like to get hot and with oil cooler it helped allot..
For the Baja 1000 ,ATV mag entered a 400x that was stock except for a set of works shock and a larger oil cooler that had a fan attached to it . Riders said they were nuts to enter and would not even finish. They won 1st in their class and ran 3 rd overall. The next year they ran the same 400x again , said they finished again with no failures. The author kept the AT V and still rides it on trails somewhere in Georgia.:)
 
i just had too :)
edited a little to keep it clean, use your imagination...............

2 stroke.jpg



nice quad though !
 
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How's the power on these 400s?
ATV MAG ..2013 400x.Top end is about 67 mph . The bottom end to mid range is equal to the 450 R Honda. mid range to top the R pulls away and revs past 9,000 the rev limiter in the 400 cut in at 8,000. The motor makes @ 35 hp at the crank and@ 25 at the rear wheel.Slip -on muffler ,jetting ,air cleaner @30 rwhp It weighs 408 lbs
 
Looking at the battery being exposed on this 400x bothered me. I feel that Honda could have done something, so I did. Its part of a plastic waste can zip-tied to the metal battery clamp. I also added a plug hook- up for a battery tender between rides.
400x Battery cover 003.JPG 400x Battery cover 002.JPG
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that should add some protection from large objects.
i always cringe when i see any atv with the battery and electronics exposed so close to the tire.
 
The ALBA Racing bumper and nerfs got here today. I just finished the install , perfect fit and powder coat finish.
400x bars bumper 001.JPG 400x bars bumper 003.JPG
 
So here I am at the pipe and head work question
. I called HRC to get some info....Surprise !.

The exhaust...The stock 400x pipe and muffler is very well made . It is fairly quiet(90db) and produces good hp . How much hp ?Well,the best aftermarket slip on for it is an FMF Powercore 4. It only makes 1 1/2 more hp than stock but is a solid 1 hp more from 3,000 to 8,000 the only one to that .FMF is fairly quiet ( 95 db) and will reduce some heat build -up in exhaust too.:)

The head... it appears that it is an all or nothing thing. The radial valve head has the best set up it can get for stock carb size .Hogging out the ports and bigger ,4 angle valves are pointless , unless you do larger cams, carb, full exhaust ,re- shape chamber and bore to 440 . If that is done another oil cooler and larger oil tank will be needed.Replacing the re- limiter box to a no -limit aftermarket one and re- gearing will be required too.
No Thanks ...:(
The only thing that can be a problem in this valve design is where the spark plug is . It appears to be slightly off- set to the exhaust valve side . This can cause a slight overheating or warping of those valves ,since the motor is not water cooled. The fix is easy... just run a one step lower than stock heat range plug.

So an FMF slip -on , Uni- filter and carb re-jet are the motor mods. It will also be the plan for the 250x too.
Keeping it simple and reliable to ride on 600 acres of sand !