The XR400 Thread

Discussion in 'Thumpers' started by Hayduke, Jan 16, 2008.

  1. KilLeR Kawasaki

    KilLeR Kawasaki Marky A

    Joined:
    Jun 1, 2008
    Oddometer:
    981
    Location:
    Littleton, Colorado
    Riding at Rainbow Falls yesterday. Two XR400s and a KLX450.

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  2. DrLewall

    DrLewall The Human GPS

    Joined:
    Aug 20, 2008
    Oddometer:
    39,059
    Location:
    Drakes Creek, AR
    Me and the fellers here went out and rode the river banks of the Arkansas River..I remember when riding in sand use to be fun :bluduh This is the first time in abt 5 yrs that she has been rode with the saddle bags and sweetcheeks off.

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  3. n16ht5

    n16ht5 ride the night

    Joined:
    May 6, 2010
    Oddometer:
    2,459
    Location:
    Arlington, WA
    Thanks for the offer, but my friend just gave me his stock pipe, so I'm all good.

    what kind of abortion of a tail light is that>??? :eek1
  4. ImaPoser

    ImaPoser adventure imposter

    Joined:
    Jun 9, 2002
    Oddometer:
    16,322
    Location:
    Cincinnati, Ohio
    I'm on the hunt for an xr400. Preferably street tagged and within a days drive back and forth from me. I'm watching the flea market here, and local Craig's list. If anyone sees anything, or knows of one, a PM would be great. :thumb
  5. xr400r

    xr400r Long timer

    Joined:
    Jan 5, 2004
    Oddometer:
    3,609
    Location:
    riding usa
    I have one that i want to sell. It is completely apart and getting restored.

    Completely.

    Cylinder bored for a JE 406 piston and HRC cam. I have a ton of spares so much so that you wont need any probably forever.

    A long list... i could provide if needed. I am the original owner and took very good care of this bike.

    You are welcome to take over the project. I have everything to finish and quite honestly could be back together in a weekend. I was just taking the motor out of the frame to paint the frame. Was going to be a winter project.

    Bike is located about 4 hours from Cincinnati.
  6. NSFW

    NSFW ktm's "the tourist"

    Joined:
    Feb 20, 2007
    Oddometer:
    17,606
    Location:
    Burbank CA
    been a few months now after 3 years in a basket. i just love my xr, the orange bikes not getting a lot of my attention lately...:clap
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    notice anything mounted on the engine?


    :D
  7. aaron2a

    aaron2a supermoto hooligan

    Joined:
    Feb 12, 2013
    Oddometer:
    691
    Location:
    canton, ms
    Wish mine had the magic button :)
  8. fuel-cycle

    fuel-cycle 3 wheels or less 49CFR571

    Joined:
    Aug 30, 2005
    Oddometer:
    440
    Location:
    Right outside this lazy summer home
    is that a whole TRX engine or just side case with appendage attached? I had heard the TRX didn't fit with out interference.

    where did you mount battery?
  9. fuel-cycle

    fuel-cycle 3 wheels or less 49CFR571

    Joined:
    Aug 30, 2005
    Oddometer:
    440
    Location:
    Right outside this lazy summer home
    imho - if your really need a damper ... then you are riding beyond the XR4 and should think about a different machine
  10. dirt hokie

    dirt hokie Been here awhile

    Joined:
    Oct 3, 2007
    Oddometer:
    788
    Location:
    Eastern shore of MD
    I don't really need a damper, but the guys I ride with who don't really need one either, lover them. The #1 improvement they say is less deflection off or rocks and roots, the bike holds a line much better.

    I am at the point of deciding if I want to dump some money into my xr 400 or juts leave good enough alone. I am really thinking about installing electric start , but my bike works so great know I am a little afraid of messing with the engine, especially since I have never messed with a bottom end before and have only done a top end on a yz 80 and cr 125 back in the day. I know I could do it, but its still scary.
  11. Stretch67

    Stretch67 Mad Scientist

    Joined:
    Mar 22, 2006
    Oddometer:
    8,112
    Location:
    Bent, But Not Broken
    I'm just getting done swapping in a 2000 TRX engine into a street-legal 2002 frame. Everything else is from my old '98 (like the old Johnny Cash song :D ).

    <iframe width="420" height="315" src="//www.youtube.com/embed/2riRAGzNzvQ" frameborder="0" allowfullscreen></iframe>

    The TRX4 and XR4 cases are just different enough to require engine mount modifications. The end result is the engine being tilted forward about a half-inch. This also requires some fabrication to the sub-frame's front muffler mount, and also the carb end of the airbox boot to make up for that half-inch.

    Here's a write-up of the process, courtesy of Booger1: http://www.advrider.com/forums/showthread.php?t=650272

    I put my battery in the same location, but used a DRZ-400 battery and box, as it's a better fit between the plastic side plate and the rear wheel (long and slim. Like me. :D )

    I used a complete TRX wiring harness, CDI box, and Regulator / Rectifier to avoid electrical nightmares resulting from XR bike / TRX engine mis-matches.





    It's doable, but takes some work. Eagle Feather didn't hang 'Mad Scientist' on me for nothing...

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    It... is... ALIVE!!!


    It starts and runs great, with 14.5 Volts DC when running :clap . I haven't ridden it yet... waiting on new (longer) Motion Pro cables, since I already fitted taller bars and Rox Risers. The stock cables are too short now.

    If a fellow simply had to keep his frame and mounts stock, you could disassemble both engines and put one back together with the TRX crank, flywheel, and starter clutch assembly in XR cases, with the TRX stator cover. Also, use the XR countershaft and clutch cover so you can keep your kickstarter. Also, you'll have to drill and tap the XR case for the starter motor mounts.

    I'll be machining my own kickstart gear bushing so the XR gear will fit on the TRX countershaft. It's right handy having a lathe. :evil

    Then I'll fit the XR kick-start accoutrement and clutch cover.

    I chose to modify the frame and keep the TRX engine unmodified and complete in order to swap in TRX engine parts as needed down the road. If I punch a holes in the cases and nuke the engine, or otherwise total out the powerplant, I can simply swap in another 1999+ TRX400EX engine. There are a few on eBay on any given day. Once in hand, plug-n-play in a few hours.
  12. XR4EVER

    XR4EVER 919 excuses to ride!

    Joined:
    Aug 29, 2012
    Oddometer:
    1,144
    Location:
    Post Falls, ID
    :bow

    Let us know how the gearing feels, the different torque curve feels (if any), and does that one have reverse? Any pics?!!
    Very cool, man. :clap
  13. Stretch67

    Stretch67 Mad Scientist

    Joined:
    Mar 22, 2006
    Oddometer:
    8,112
    Location:
    Bent, But Not Broken
    It doesn't look much different, 'cept for the lump under the carb. Booger1 provided relevant pics in his post that I linked.
    My battery setup is a bit different, with three welded-in mounting points instead of Booger1's two-point setup...

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    Ignore the 'rub mark' on the back of the battery box. I sanded away a rib molded into the plastic, making the back
    of the box smooth. I removed the rear shock during mock-up, and made sure the rear tire clears the battery box at full
    compression.
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    It is a bit crowded under the seat now. You'll recognize the Starter Relay, Regulator / Rectifier, and Main Fuse.
    The CDI box is in the regular XR place, behind the engine on the left side.

    On a TRX ATV, the CDI box is on one end of the frame under the handlebars, while the Regulator / Rectifier is on
    the other end, hanging under the left rear fender. Scads of cutting and splicing were involved here to make all these
    items fit in this one spot without wads of wire in one place and not enough length in others.

    The small black Bosch lighting relay is for the bike's lights. I'm running dual H4 headlights from a Buell Lightning.
    Lotsa watts flowing in there... I don't want to melt the switch and wires.

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    From my readings here and on ThumperTalk, the TRX engine's gearing is about 8% lower than that of an XR400. That
    can easily be compensated for with sprocket changes. I have a 14, 15, and 16 front, so I can swap around and
    experiment. I had a 14 on the bike before, so with lower gearing in the TRX engine, I might run a 15 on the front and
    see how it feels.

    Also, the TRX4 cam reportedly offers more lower end torque than the XR4, which will be great for singletrack.
    The bike will see very little street use at all, so low gearing and good torque at the expense of high-RPM horsepower
    is just fine with me.

    No reverse on mine. There are times when that would be handy, but those engines are about 500 dollars more.
    I couldn't justify the expense.
  14. LtsGoRyd

    LtsGoRyd Been here awhile

    Joined:
    Apr 20, 2008
    Oddometer:
    162
    Location:
    Front Royal ,VA
    Man, that is awesome. Sooooo wishin I had a "magic button." I got my cherry 04'(don't ask about swingarm...she's stuck for now:cry) back in July of this yr. Got her titled and legal, runs like a champ. Cranks pretty easy. 2 prime/1 kick when warm, and if it sits for 2 weeks, go through crank procedure twice, 3rd time cranks right up. :D I've got Ricky Stator, new stator side OEM gasket, regulator/rectifyer, flasher and trail tech battery ready to install, but I am electrically challenged, to put it mildly. Hopin I can bribe a friend/inmate soon :evil. Can you post a couple more photos on battery box , and how/where it's mounted, type of box used. I think I saw DRZ type box and battery, but not sure. Man, the folks on this ADV site are too smart for my lint filled wallet, but oh well, sure is fun. Sure hope I get to ride with some folks from here soon, ride safe. joe:freaky
  15. LtsGoRyd

    LtsGoRyd Been here awhile

    Joined:
    Apr 20, 2008
    Oddometer:
    162
    Location:
    Front Royal ,VA
    Dang you musta been readin my mind. Careful, kinda dangerous in there....Now, if I could just locate that electrician :D.
  16. XR4EVER

    XR4EVER 919 excuses to ride!

    Joined:
    Aug 29, 2012
    Oddometer:
    1,144
    Location:
    Post Falls, ID
    Thanks for the follow-up. Do you know if the gearing difference is in the overall final gearing, or are the ratios of, say, first and second lower and fifth is the same as the xr4? (Same 1st-5th ratios with lower final ratio, or just a wider-ratio transmission?) Just curious for my own schemes.... :evil
  17. Stretch67

    Stretch67 Mad Scientist

    Joined:
    Mar 22, 2006
    Oddometer:
    8,112
    Location:
    Bent, But Not Broken
    First gear is about the same... the upper ratios are progressively lower in the TRX.


    XR400R
    2.830, 2.620, 1.840, 1.400, 1.120, 0.930


    TRX400EX
    2.826, 2.916, 1.937, 1.473, 1.181, 1.000
  18. bitwrench

    bitwrench ADV SUMO

    Joined:
    Dec 5, 2009
    Oddometer:
    207
    Location:
    Im back in SoCal again, sorta..Ca.
    Greetings,
    I get to join the XR400 club with this prime example rescued from the corner of someone's garage. The Dunlop K695 rear and K490G front are long out of production. I believe these tires rolled off the showroom floor..



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    Supa Low Hour
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    Guard Dog on doodie
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    Svelt
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    I gave my credit card some exercise by purchasing various controls
    and sundry items..big tank, Pegs, gearing etc...
    I get a trailer hitch on the Camry next weekend. Then I work on getting it 'streetable'. HOOTERS...early X-mas for this dog.
  19. xr400r

    xr400r Long timer

    Joined:
    Jan 5, 2004
    Oddometer:
    3,609
    Location:
    riding usa
    Nice find you lucky dog. good bike for sure
  20. NSFW

    NSFW ktm's "the tourist"

    Joined:
    Feb 20, 2007
    Oddometer:
    17,606
    Location:
    Burbank CA
    nice barn find!

    exact same condition when i found mine 5 years ago, not a single scratch and the header has the blueing.