Back2Orange - NooB '02 400 EXC owner le questionies...

Discussion in 'Thumpers' started by Rapid Dog, Jun 12, 2013.

  1. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    ...looks like I'll be picking up a spankin' old 2002 KTM 400EXC'er this weekend from an inmate if all goes right. (props to Joel and ConTeacher)
    130hours per the PO.

    I'm gonna need to go through it stem to stearn.
    All in all evidently a decently maintained bike that needs some LUV.

    I figure I'll do:
    valve check
    wheel bearing check
    swingarm bearing check
    head bearing check
    new tars
    and a general scrubbin' an' spiffin'

    Been reading all the EXC threadness, but still a few things to sort.
    I'll have a few questions as well as I go along since there's no owners manual, like:

    Recommended sparkplug? Should I use Iridium?
    Oil weight?
    Who's got a Scott's stabilizer I can buy from ya...:norton

    She looks like a real narsty dirtybike...

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
    #1
  2. bobfab

    bobfab Long timer

    Joined:
    May 11, 2009
    Oddometer:
    1,727
    Location:
    Westminster CO
    my good friend just bought the same exact bike im :ear
    #2
  3. Droptarotter

    Droptarotter Long timer

    Joined:
    Jul 11, 2007
    Oddometer:
    1,484
    Location:
    Cloverdale,BC
    Hey Randy;
    Make sure the chain adjuster are not seized. I drill a 1/8 hole in the bottom rear of the swing arm for a water drain.

    The chains like to run what looks like really loose on these bikes......best way to adjust the chain for the first time is to remove the shock (it's easy) and raise the swing arm in line with the countershaft/swing arm pivot to get the proper tension.

    There is a oil filter screen under the engine that needs to be torqued properly.......most guys do them too tight and bugger them up the next time they try to take them out.
    If yours is buggered get a new screen with a bolt head.

    Run 20/50 oil........I like Chevron Delo 400.......

    Have fun!!
    #3
  4. Baja Dad

    Baja Dad Long timer

    Joined:
    Jan 3, 2011
    Oddometer:
    2,373
    Location:
    Norco California
    here is my 01 400 rebuild
    [​IMG]
    #4
  5. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    ..hooyah! Frame off resto...nice.
    I promised myself I'm not going overboard on this one.
    Gonna be a get dirty trailbike I can drop and not fret about.
    Low budget but well maintained.

    I do need a Scott's stabilizer'n some stuff though...:wink:
    #5
  6. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    ...soon come...:norton
    #6
  7. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    ....got 'er done...

    [​IMG]

    [​IMG]

    [​IMG]
    #7
  8. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    first a scrub down, she's a dirty bitch but runs fairly well.
    Needs huge TLC...
    The PO move the ECU to under the seat. Some sort of mod I don't understand. I mounted back where it belongs on the steering head.
    Questions to come... :ear:ear:ear

    [​IMG]


    [​IMG]
    #8
  9. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    ...there, that's better. Cleaned up pretty good.
    Managed to get the valves set.
    Intakes were tight
    Exhausts were loose... :ear

    Turnsinals and brake light don't work
    Turnsignal switch has been buggered.
    It's got the TrickDualSport Light kit. Not sure how that's wired, much to sort there.

    [​IMG]

    First question, is the adjuster knob on the carb (bot left) fuel mixture or idle?

    [​IMG]
    #9
  10. MotoChris521

    MotoChris521 Long timer

    Joined:
    Aug 30, 2007
    Oddometer:
    1,134
    Location:
    SoCal
    Idle speed
    #10
  11. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    Thanks Chris.

    Here's another:

    Bike runs good but when running and you let it die, there's a top-end rattle ...noise during the last couple rpm's.
    Sounds like a cam chain noise.
    Not sure this is normal or a sign of something 'else'.

    I have set the valves already but not run it yet.
    Intakes were tight, exhausts where loose.

    Over at KTM Talk someone suggested...
    This bike has the decompression cable disconnected..for what I do not know...
    #11
  12. bobfab

    bobfab Long timer

    Joined:
    May 11, 2009
    Oddometer:
    1,727
    Location:
    Westminster CO
    My buddies is the exact same way. Decomp cable disconnected and a slight rattle at low "Shutoff" RPM's. Im all ears here!
    #12
  13. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    :ear
    #13
  14. GR0NK

    GR0NK Got some screws loose!

    Joined:
    Sep 24, 2006
    Oddometer:
    3,971
    Location:
    Stuck in 80s
    The decomp is auto, makes no difference if the cable is connected or not. The noise is normal. About the decomp on pre 03 bikes though, is the stop on the cam gear. It's a bolt with a nylock nut on it. In 03 they changed it to a riveted pin. If the nylock nut comes loose and the parts fall out, it's not pretty. Very rare to happen but it has. The fix is a new cam gear which isn't terribly expensive, under $60 IIRC. You'll need a new cam in 200 hours or so as the water pump seal will groove the end of the shaft. I would just wait and do it all later.

    If you follow the 400 discussions anywhere, you'll surely come across the mention of the 453. The 453 is the best RFS motor KTM never made. Basically it's the 400 crank (short stroke) with a 525 cylinder (and a special piston from Thumper Racing) and it bumps the displacement to 453cc. You toss the anemic 400 cam and use the 5521 cam (stock cam on 450 and 525 EXCs) and that gives you a great all around motor for low bucks. It's still docile on the bottom but it comes alive on top and revs out good due to the short stroke and the better cam.

    At 300 hours you're going to start running out of adjuster as the intake valves get tighter and start knife-edging. Send your head to Dave Hopkins and have him do his stuff. Stainless steel Kibblewhite valves at the very least. If you are going to bump up the displacement, get the intake valves oversize by 1mm and unshrouded. You're then only an 806 (or my fav an 833) cam away from serious fun. :D

    I love these motors. My favorite is the 540 but that's a long stroke crank so not quite the snap and smoothness of the short stroke crank. Ride it stock and enjoy it for now, it's an awesome bike. :freaky



    Sean :bmwrider
    #14
  15. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    yaeh baby! Now that's some relative info!
    Thanks for that.

    Who is he. How does one contact him, eh? :ear
    #15
  16. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

    Joined:
    Apr 14, 2007
    Oddometer:
    8,931
    Location:
    Middle Park, Brisbane, Australia
    The ECU was moved to the airbox to give it more steering lock on left turns.

    Make sure you adjust the steering stops so that the forks won't hit the ECU if you are planning on keeping it in the original location.
    #16
  17. GR0NK

    GR0NK Got some screws loose!

    Joined:
    Sep 24, 2006
    Oddometer:
    3,971
    Location:
    Stuck in 80s
    http://www.djhcyclesport.com/

    He's very active on KTMtalk, one of the engine gurus there. You might want to join up there for everything technical and also for a really nice discount at Munn Racing if you get a lifetime membership. :wink:



    Sean :bmwrider
    #17
  18. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    Yeah I'm on that. Just ordered some stuff from Munn yeterday, best prices I could find on anything.
    I'll look into the motor dude.
    Gracias...

    You know, I did the Athena 290 on my WR250X and it really made the bike alot more vibey. I'm reticent to do a big bore kit on this one.
    I'd like to hear from someone who did this... :ear
    #18
  19. Rapid Dog

    Rapid Dog bikes, booze, broads...

    Joined:
    Oct 28, 2003
    Oddometer:
    10,377
    Location:
    Strangel Living West of Hell, SoCal
    aha! Thanks, I will check that out when I get her off the lift...(mental note to self...)
    #19
  20. GR0NK

    GR0NK Got some screws loose!

    Joined:
    Sep 24, 2006
    Oddometer:
    3,971
    Location:
    Stuck in 80s
    My buddy did it and it really woke the motor up mid to top. The beauty of the 400 is the docile bottom, it gets traction out of the hole, and you don't want to mess that up. The 453 mod builds better mid and a really good top end without sacrificing the awesome bottom. My Dave Hopkins built 540 was a 60hp mini monster that would go 185 km/h on pavement, but on gravel my 540 and my buddy's 453 were side by side at just under 160 km/h, with the excess power just being turned into roost. I'm 6'2", 225lbs so my 540 didn't beat me up too much but at 5'8" 175lbs, my buddy's 453 was an easier and smoother bike for him to handle and it made him a faster rider. Most people will try the bigger motors and like the boost, but then they go too big and find that the excess is just too much and they come back to the combo that worked the best. IMO if you start with a 450 or 525 that best bang combo is the 540 and if you start with a 400 it's the 453. Going bigger just makes you work harder and wears out parts faster. :wink:

    I have not noticed any increase in vibes from any of the BB KTMs I have ridden. These are thumpers so it is normal for some vibes but the short stroke 400 crank is already smooth to begin with that I wouldn't worry too much about it. When Dave built my 540 he aligned, welded and balanced the crank and it was very nice. Unfortunately, that process makes the crank a solid non-rebuildable chunk so that is the con.



    Sean :bmwrider
    #20