Yamaha xt350/400 hybrid!!

Discussion in 'Some Assembly Required' started by MILLENNIUM FALCON, Feb 21, 2012.

  1. dirt hokie

    dirt hokie Long timer

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    Looks like it would be a blast on gravel roads. Makes me want to build a bike.
  2. Ron Bullard

    Ron Bullard Been here awhile

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    Man, that is super clean. Excellent job!!
  3. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    Thanks! I hope to get some more miles on it, and take some video for you guys.


  4. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    I posted this on Dotheton so I thought I would share.

    "I have done quite a bit of searching but have not found the info I need. If you have a minute to help me out I would appreciate it. My bike is an 81 xs400 with vm30's I am running K&N pods and 2 into 2 exhaust. I am running 150 main jets and 25 pilots. The air screw seems to work best at 1 turn out from stop. The clip is on the middle slot on the needle. I enclosed some pictures of my setup. I also have a link to a video of the problem In the video you can see if I blip the throttle from an idle id stumble and or dies, but If I blip it from a high idle or slightly higher rpm it gives me much better throttle response. at all other RPMs throttle response is decent. Any help would be appreciated. I just didnt want to spend any unnecessary money on jets in the wrong direction. Thanks again. Let me know if you need more info."


    Pics.....[​IMG]
    [​IMG][​IMG][​IMG]

    Video.....
    http://www.youtube.com/watch?v=a4uQfdFEPvE&feature=plcp
  5. Pete-NZ

    Pete-NZ Long timer

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    to me it sounds as if you are running to lean of the bottom , try a 30 pilot then play with needle and
    air screw settings... there is another adjustment... the emuntion tube , the brass tube with small holes
    the main jet screws into.. ths tube is for primary vacume to assist the carb to lift the fuel at
    low vacume/low rpms , the vacume around this tube is adjusted by the air screw (mixture screw as some call it)
    There are diffrent tubes with bigger or smaller & number of holes if all ealse fails you may need to try
    a tube that gives a diffrent amount of vacume.. Raising the fuel level in the bowl can help so the fuel hasn't got
    as far to lift.. ( the same carb on 2 diffrent motors can have diffrent fuel levels , its a setting)
    two other adjustments are...
    Needle tapper ...
    Diffrent slides that have a diffrent cut away angle...

    The pilot jet / needle / air screw these usealy sort the prob....
    just try lifting the needle..get the needle jet working at slightly
    lower vacume/rpms.. see what happens..

    PS...
    Those air filters are not good either , they slow the air flow down..
  6. gkam

    gkam Been here awhile

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    Nice bike! Great job!
  7. EnduroRdr

    EnduroRdr Woods Racer & D/S Rider

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    Really nice build, If you dont mind sharing resources, where do you source pre-bent pipes?

    I could use these on my projects.
  8. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    Not at all......I got the pipes from summit racing's eBay store. $12 a piece. They worked great!
  9. Mambo Dave

    Mambo Dave I cannot abide.

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    Thanks for posting the link to your build thread here. Really like the styling of the bike - what a neat machine.
  10. itrack

    itrack Been here awhile

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    Sorry if I missed the answer but what gauges are those off of? How hard were they to wire up? Any details would be appreciated.
  11. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    Thanks. The gauges are from trailtech.com. This model is the vapor. They are super simple to hook up. I added the indicator lights so that made for a little more wiring. If you just o with the basic dash it's just one wire for the tach, one for the speed and one for engine temp. Plus 12v. The unit is self powered if you don't feel like hooking the power up. All wiring instructions can be found at www.trailtech.com good luck.


  12. cjw

    cjw Adventurer

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    looks to me that those are 2 stroke carbs.no accelerator pumps?if no accel pumps you will never get rid of the off idle stumble.
  13. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    I made a few adjustments and changed the pilot jets now it is running nearly perfect.
  14. pdxmotorhead

    pdxmotorhead Long timer

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    Just a side theory,,, but,,, if you make a couple shields for the air filters it may help overall run-ability,
    with the exhaust placement and the hot air of the motor (Both variable) the potential air temps going into the motor will be all over the place, and heat definitely changes effective mixture. If the guage cluster unit you bought has a extra input or two I'd add a intake temp sensor and a exhaust thermocouple. Instant tuning assistance.. Temp sensors are < 20 bucks if you shop...

    Great lookingn bike BTW>.. Like the mix of flat track, moto and Old school Steve mcqueen in there... :)

    Dave
  15. rickburnout666

    rickburnout666 n00b

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    Great looking bike, i have updated my XT250 to a XT350 engine plus loads of other updates updating it to a WRXT 350X Supermoto, Have you kept the original Carbs & did you need to upjet them for the filters & pipes as i am doing the same & need to know what jets to fit ?
    Hope you can help
  16. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    Thanks man! My bike is running an xs400 twin so my carbs and jetting will be completely different. However, I did have to go with bigger jets. I also changed from the vacuum slide carbs to vm mikuni's. Do you have a link to your build? I would love to see it.
  17. Bambi

    Bambi Been here awhile

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    Hi Falcon,
    you did a brilliant job! I like bikes like your's very much. I still remember being struck when German enduro-racer Rolf Witthöft some kind of siamesed a KLX 250 rolling chassis with a bored-out Z 440 (soft-chopper!) engine of 501 cc to run it in the then new 4-stroke-class over 500 cc. Mid-sized singles are great off-road but I like the smoother character of a twin-engine soo much ...
    I'd also like to see Rick's bike!
    Kind regards, Bambi
  18. Hondo

    Hondo What if it's a Samsquanch?

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    This project id flat-out bitchin'!

    Congrats on a great job! :clap

    The only thing that I would add is some type of inner fender or flap that would protect the shock and air filters from thrown dirt.
  19. MILLENNIUM FALCON

    MILLENNIUM FALCON Been here awhile

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    Thanks hondo! I totally agree on the mud guard. I have since made a temporary guard out of a mudflap.
  20. kellymac530

    kellymac530 motorcycle addict

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    Love the bike Falcon.
    The tail hump and aluminum front fender and simple styling give it a vintage Rickman flare but with your own style and ideas. Very cool.

    I am curious on the rear wheel set up. Why the 19" rear wheel? Is that a front tire on the rear?
    I just do not see much in the way of DOT rear tires in 19" and in Cali DOT can be a big deal. I like the wider rim though.