The XR400 Thread

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

  1. Ed@Ford

    Ed@Ford Long timer

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    Thanks LUKE....now I understand the REAL failure mode!
  2. The Shred

    The Shred Airventurer

    Joined:
    Apr 29, 2010
    Oddometer:
    425
    Location:
    NY82: ALB 156 @ 13

    I turned the bolt back and forth with a 4' pipe on a breaker bar with a 6 sided socket till it would finally spin all the way around. Then used a large hardware store bolt as a punch to hammer it out. (hold the punch with vise gripes.) The swing arm bolt gets ridges worn into it on different sides in different locations, so if your hammering and it won't move or stops moving turn it a little and try again. I was swinging a big sledge thinking I was going to miss and wreck the bike and it never budged. Came back a day latter and drove it out with a mallet by hitting and spinning it. Try using penetrating oil between the engine and swing arm too. When you put it back together waterproof grease the entire bolt. It works better than never seize IMHO. Hope this helps. Good luck.
  3. Ed@Ford

    Ed@Ford Long timer

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    THANKS!! I may be able to beat this after all!
  4. RideFreak

    RideFreak Torque Junkie

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    Out in the NM Dez somewhere
    I was never an autoclutch kinda guy but I got in on a group buy and there's a Dynaring sitting on the bench for my 300XCW that I haven't installed yet. :cry I did get to ride a KTM525 (before and after a dynaring install) and it totally transformed the bike for woods riding. Everything is ridden a gear higher, less gyro effect from the lower RPMs, I was much smoother and as a result, faster with the autoclutch on that bike.
  5. farrington300

    farrington300 No wait....What?

    Joined:
    Sep 27, 2009
    Oddometer:
    528
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    Denver CO
    A dyna ring is really on my short list of mods. I would be buying it for the "no stall" feature. It would help with having to kick start on the side of a hill. There is some info on TT to read. It shares some pros and cons. Overall, it sounds like a good buy from what I have read. Im wondering weather it will hold up to abuse.


  6. grub

    grub Requires Supervision

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    Waiting for a green light on the red line
    My Revloc Christmas box arrived last night, hope to install it this week.
  7. DrLewall

    DrLewall The Human GPS

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    Drakes Creek, AR
    a buddy of mine has a revlock on his XR650..takes some gettin use to..he loves it..me, not so much..but thats cause I am not use to it..am old school..I hear they are in the process, if they havent already, made a unit that will allow you to bump start..that was the only draw back I saw..sometimes a bump start is needed!
  8. Davidjohnson

    Davidjohnson Been here awhile

    Joined:
    Jul 15, 2010
    Oddometer:
    177
    Location:
    South Texas
    Any suggestions? The bike is a '98 model and has been uncorked, but stock otherwise.

    thx
  9. birds

    birds Been here awhile

    Joined:
    Aug 11, 2010
    Oddometer:
    253
    Location:
    North NJ
    I have some questions about carb tuning

    My carb is in dire need of gaskets, and I want to make sure the jets are right, as I had an overheating problem recently (maybe too lean?). I have no idea what is in there now. What jets should I start with while trying to tune it?

    - '99
    - uni air filter (bike came with k&N)
    - no snorkel
    - seems to be stock header with FMF Megamax muffler
    - sea level

    Any other information I need to find out?
    Any things I need to order other than the gaskets and jets?
  10. RideFreak

    RideFreak Torque Junkie

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    Out in the NM Dez somewhere
    The dynaring allows you to bump start on bikes with a hydrolic clutch depending on which setup is used. I don't care for the method they use though (pressurizing the Master cyl res)
  11. farrington300

    farrington300 No wait....What?

    Joined:
    Sep 27, 2009
    Oddometer:
    528
    Location:
    Denver CO
    I would start your jetting quest at 60 160, and go from there.

  12. HopheadRed

    HopheadRed Adventurer

    Joined:
    Mar 16, 2011
    Oddometer:
    15

    I'm out of town for work until the end of June, but I've left the bike at John's shop (Cyclecraft Motorcycles, NJ - recommended by folks here). He's got about 10hrs into it so far and we've replaced the following: brand new stator (ricky stator 200w), ignition coil (ebay - working), CDI box (ebay/existing same issue), and John told me today after speaking with some people, he replaced the crank rotor (magneto?) and still having the same issues. He also said he's got continuity on all wiring, terminations are good, and everything is connected the way it should be. John is 100% convinced it's an electrical issue -- but after replacing all the above parts, whats left electrically? I guess I'll see if I can find a wire harness on ebay...

    Any further thoughts?!? I'm baffled, i thought these things were as easy as a lawnmower to work on..
  13. laramie LC4

    laramie LC4 crash test dummy!

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    got correct timing?

    only a few things keep an engine from running..... fuel, spark, compression, timing.

    if your mech hasn't been able to solve the problem yet, after throwing all these parts at it, i hope he doesn't plan on charging you too much. at this many man/mech hours, you could have bought another xr....:deal


    oh, and i'd have another talk with your buddy about what he messed with on the bike. a screw in the valve? sounds like someone thought he knew how to do something. if he had the engine apart, he could have easily screwed up putting it back together.


    good luck,

    laramie :beer
  14. HopheadRed

    HopheadRed Adventurer

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    From my research, I thought timing would be the issue. When I mentioned this to the mechanic, he said absolutely not and almost sounded offended saying, it's 100% electrical. The engine has never been apart, minus John the mechanic, taking the head off to discover the screw. He has also gone over the bike and said it's mechanically in top shape.:baldy:bash
  15. Ed@Ford

    Ed@Ford Long timer

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    the fact that the head has been off tells me double check cam timing

    I believe this engine has a spark at about 10 degrees before every top dead center....but it also has a spark plug wire you can get at with an old fashioned timing light that has a inductive pickup which clamps over the spark plug wire....if you remove the small plug on the alternator, there is a set of timing marks in there...T & F...F = firing....

    You'll probably have to have someone kick it over, while the other looks in the hole....if the timing light doesn't flash....well no spark....if it does flash and you see "F" in the hole...see page 16.9 of the service manual....you have properly timed spark

    The process for cam timing is chapter 7 of the manual...it involves removing the cam cover....not a trivial process
  16. HopheadRed

    HopheadRed Adventurer

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    15
    I'll be sure to pass this info along to John, but the bike wasn't running prior to the removal of the head. As I mentioned before, he was confident it's not a timing issue and was almost offended when I mentioned it. Lol...I'd like to not doubt this guys mechanical abilities, especially since he came highly recommended by more than one person here, but how it's such a simple machine! I know this thing is killing him...but not quite as much as its killing me i bet! :umph
  17. Ed@Ford

    Ed@Ford Long timer

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    DUH!! My bad for failing to not properly note it was not running B4.....probably because if the valve being jammed with the screw

    my xr used to be a real PITA and not even pop....but if I shoot some starting fluid or butane lighter fuel in thru the bowl overflow on the LH side of the carb (with the throttle open) then close the throttle, it would always pop and run up enough to tell me "the normal fuel system has a problem"...it found a plugged slow jet....and upon removal to clean it....the main jet had vibrated out and ended up in the float bowl. Sure...this is a very odd coincidence...but it did happen!!
  18. HopheadRed

    HopheadRed Adventurer

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    Oddometer:
    15
    I was really hoping that was going to be the issue! Unfortunately, it's compounded since than! Thanks for your input though, I appreciate the help.
  19. Luke

    Luke GPoET&P

    Joined:
    Aug 25, 2004
    Oddometer:
    4,260
    Location:
    Beaverton, OR
    A few random thoughts:

    So it has a strong spark, but the mechanic is 100% sure the problem is electrical. Uhhhh.. ok. The spark could be at the wrong time, but the most likely cause of that is a sheared flywheel key.

    Not that I think you need one now, but for general reference you can make your own peak voltage adapter

    [​IMG]

    The half wave version is what the manual calls for, the full wave version is IMO a little easier to use as you don't need to worry about polarity.

    [​IMG]

    Hook it up to a good digital meter (a $30 radioshack one is fine, the $4 harbor freight meter is not) and it will save hours of guessing.


    After John found the screw in the valve, did he check that the valve sealed properly? I would expect the valve to bend a little from that.

    Is the choke plate in the carb in good shape? Missing a screw???? How about the spring on the flap. Is it holding the flap closed?

    I'd change the pilot jet to 62. On my bike, 60 ran slightly better, but 62 made it easiest to start. It was very hard to start it with a 55, even with e-start, even at highish altitude.

    Speaking of.... the drill test may not mean anything. The e-starter doesn't turn the motor over fast enough to get the CDI to fire, converted bikes usually use the TRX CDI which will fire at low speeds. The drill may not be turning the motor fast enough to get spark.
  20. Ed@Ford

    Ed@Ford Long timer

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    Dearborn MI
    LUKE:

    That peak voltage doodad is SLICK!!!