The KTM LC4 Reliability research thread

Discussion in 'Thumpers' started by demononthebrakes, May 25, 2006.

  1. wrk2surf

    wrk2surf on the gas or brakes

    Joined:
    Dec 16, 2007
    Oddometer:
    8,711
    Location:
    THE exact center of California/Bass lake/Yosemite
    on my rebuild the bypass piston seemed stuck at the top of the bore and took some work to get down, guess thats why they have the holes drilled to the side of it... dont know if that was an issue or not on my conrod melt.
    #81
  2. brents347

    brents347 Trusting my Cape...

    Joined:
    Mar 5, 2006
    Oddometer:
    4,390
    Location:
    Where the hell is Truckee, CA?
    1. Bike:
    2. Year:
    3. Bought used or new:
    4. Current mileage:
    5. Modifications done:
    6. Mechanical work done:
    7. Upgrades done:
    8. Current tires on the bike:
    9. Percentage of road versus dirt use:
    10. Would you buy another one?:
    11. Did you replace the main shaft bearing (if applicable):
    12. Pic of the bike if available:


    1. 660 Rallye
    2. 2002
    3. Used, in boxes
    4. Mileage unknown. 2, maybe 3 Dakars + who knows what else.
    5. Pretty much none? High fender!
    6. None, all, depends on how you look at it.
    7. New Renazco at builds' end! CA plate.
    8. Michelin Baja F & R
    9. 90% dirt, 10% road
    10. A newer one, If I could.
    11. No. I actually know nothing about this.
    12.[​IMG]

    [​IMG]

    When I first got the bike I was posting questions like "what is this part" and "where does the battery go", but I pretty much have the bike all figured out now.
    #82
  3. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,567
    Location:
    Circumlocution Office of Little Dorrit
    Next oil change I'll be pulling mine. Not sure why something with a spring doesn't make the maintenance schedule... :scratch
    #83
  4. dwayne

    dwayne Silly Adventurer Supporter

    Joined:
    Feb 7, 2006
    Oddometer:
    7,648
    Location:
    wheelie in purgatory, Calgary
    Intresting...I noticed some inconsistancies with mine as well.

    On the 400 that went boom, there was NO check valve, on the 620 I bought to rebuild and replace the 400 with there was no spring. the spring that was in the 400 was about .880" long (spec is 1"). I KNOW the 400 hadn't been apart since I bought it (I put about 50 hours on it it is a 1998).
    #84
  5. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,567
    Location:
    Circumlocution Office of Little Dorrit
    KTM LC4 crankcase bypass valve and spring info here:

    http://www.advrider.com/forums/showthread.php?t=57107&page=12

    I am guessing it allows the oil to build up in the crankcase and allow for oil height measurements (dipstick/sight glass) when the bike is off. I was thinking if it is stuck open the oil height measurements would be off. If it was stuck closed that would be very, very bad of course but it shouldn't eh?
    #85
  6. coughinhk

    coughinhk CoughinHK

    Joined:
    Feb 6, 2008
    Oddometer:
    83
    Location:
    Bonkers Honkers
    1. 640 Prestige SM
    2. 2004
    3. Babyed (barely used, still 100% standard)
    4. 17,000 Km
    5. Tuning (170 main, 1.1 air, 42.5 pilot, open airbox, no SAS or EPC, WRP Lite race can) and rear rack...and .....wait for it....a top box :puke1
    6. None
    7. Vapor Dash
    8. Michellin Pilot Power
    9. 99% road (there's a short dirt road near my home I have fun on just before I wash her)
    10. I love this bike but I want the 690
    11. no
    12. Before the top box shame and WRP (wow, great can !)

    I also want to take the opportunity to thank everyone here. I've got so much good help and advice, especially about which brew to enjoy while I try to sort my bike. :1drink

    THANK YOU ! :clap

    Attached Files:

    #86
  7. coughinhk

    coughinhk CoughinHK

    Joined:
    Feb 6, 2008
    Oddometer:
    83
    Location:
    Bonkers Honkers
    Any idea what causes this ? Did you find out ? :ear

    My bike has a cold oil level about 1/3 up the sight glass but when hot it is right at the bottom of the sight glass. According to the manual it should be above the cold level, not below it. :huh
    #87
  8. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
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    14,567
    Location:
    Circumlocution Office of Little Dorrit
    I'm still unsure, but you are right the sight glass should show a higher level when hot than when cold (thermal expansion of oil increases its volume). I am pretty sure the bike must be very level when reading the glass, and always wait a few minutes (5 at least) before reading to allow the oil to drain down and settle in the crankcase, or be diligent and wait for the reading to stabilize.
    #88
  9. GodSilla

    GodSilla I did that.

    Joined:
    Sep 21, 2006
    Oddometer:
    12,174
    Location:
    GodSowncountry Australia
    UPDATE:
    2003 640 Adventure, now at 45,000 km's. Last 5,000 k's (4 weeks since oil change and tune up, also replaced coolant pump and thermostat) the bike hasn't missed a single beat, hasn't lost a single nut or bolt, and still runs like a freight train. ZERO problems.
    It dragged my sorry arse, plus luggage and spare fuel, through some of the most isolated parts of the planet.

    See ya in another 5,000.:D




    PS Hi Meaty :wave
    #89
  10. braaap!

    braaap! Long timer Supporter

    Joined:
    Mar 16, 2005
    Oddometer:
    4,168
    Location:
    Here and There
    Yes, you are truly blessed, and immune Godsilla... the 2003 model is unquestionably, the most reliable and un-problematic of them all...



    tick, tick.... KaBoom.

    btw, my bypass valve cap was stuck up inside the case too... spring free length measures 24.34mm! and there where several lumps of metal inbetween the spring coils... I got lotsa parts to order and oilways to flush:lol3
    #90
  11. coughinhk

    coughinhk CoughinHK

    Joined:
    Feb 6, 2008
    Oddometer:
    83
    Location:
    Bonkers Honkers
    Could it be the oil ? I'm using a mix of 15W50 and 10W60, both Shell Helix. Yes, I know, I shouldn't follow a mate's advice....:cry She isn't burning oil, just this weird hot oil level. I don't really care, so long as she keeps a grin on my face, but all the [​IMG] REBUILD HORROR [​IMG]stories here stop me enjoying my beer.
    #91
  12. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
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    14,567
    Location:
    Circumlocution Office of Little Dorrit
    REBUILD HORROR stories are just because the LC4 model line is getting old. Pretty soon we'll all be gummin' our lips and poppin' geritol like qualudes...

    Mixing oils shouldn't change the laws of physics; they'll still expand under heat.
    #92
  13. GodSilla

    GodSilla I did that.

    Joined:
    Sep 21, 2006
    Oddometer:
    12,174
    Location:
    GodSowncountry Australia
    Hi Braaap.

    Immune?
    In my dreams.:lol3 My ride/life can turn to shit as quickly as anyone's.


    Blessed?
    Most definitely, after 11 days on the road with perfect weather every single day. Somebody upstairs smiled on me for sure. :bow


    Lucky?
    Somewhat, although I think you make your own luck to a degree.:thumb


    Happy?
    As a pig in shit mate. As long as my KTM doesn't do an impersonation of a hand grenade.
    #93
  14. rxcrider

    rxcrider Long timer

    Joined:
    Apr 19, 2007
    Oddometer:
    1,510
    Location:
    N Ridgeville OH
    You mentioned blue fork seals... Do you have 40mm inverted WP forks? If so, where did you get the seals and how are they working? KTM doesn't even supply 40mm seals at this point and the K&S set I got last year lasted 1/2 a season. Also, what seal skins are you running?
    #94
  15. Beez

    Beez Given to fly

    Joined:
    Aug 20, 2004
    Oddometer:
    6,016
    Location:
    Framingham, MA
    1. Bike: 620 RXC
    2. Year: 1997
    3. Bought used or new: new
    4. Current mileage: TK
    5. Modifications done: Tag 1 1/8" handlebars, Acerbis rally guards w/ spoilers, RAM mounts, mainshaft roller bearing upgrade, snorkle removed, T-vents on carb, springs replaced for my weight
    6. Mechanical work done: Normal maintenance, some mods to make the TM40 fit
    7. Upgrades done: KTM aluminum skidplate, Scotts sharkfin, Mikuni TM40 pumper carb, SXC muffler, solid magnet stator, heated grips, power for heated vest & GPS, set of 17" motard wheels, gel seat, Touratech tailbag, Moose spare tube fenderbag
    8. Current tires on the bike: MT 21
    9. Percentage of road versus dirt use: 50/50
    10. Would you buy another one?: yes
    11. Did you replace the main shaft bearing (if applicable): Yes
    12. Pic of the bike if available:
    [​IMG]
    #95
  16. clintnz

    clintnz Trans-Global Chook Chaser

    Joined:
    May 17, 2004
    Oddometer:
    4,834
    Location:
    Rotoiti, North Is, New Zealand
    All hail the everlasting 03 LC4 640 for it is truly an immortal & everlasting motorcycle :pope

    75 500 km on mine now. Might give the carb a birthday as she's started using a touch more fuel than normal, & maybe a new thermostat as she got a little hotter than normal a couple of times recently too. Otherwise all good.

    That head & piston look nasty Braaap, mine looked mint when we gave the head a service @ 50k km, maybe it's the higher temps in Oz?

    Cheers
    Clint
    #96
  17. samolapraga

    samolapraga n00b

    Joined:
    Jun 2, 2006
    Oddometer:
    5
    Location:
    Bucharest
    I read this topic before going on my trip, i never thought i would get to post in it too. I have a problem, BIG one that is, so i'm asking for your advice.
    My bike is6 year old, 2003 that is and 40000kms on the clock. Being in Altai mountains, near Ak-Tash and going to Mongolia, i dropped it in a big pond, with some mud in it. Not getting to stop the engine quick enough, it got a few gulps of dirty water in the carburettor and then in the engine. Changing the air filter and the sparkplug seemed to make it work fine at that time, so i went on with it. But after 500km or so, it started consuming lots of oil. So much that it freaked us and decided to head back to Barnaul, where we opened the engine and found the piston rings were worn out. Changed them, and the bike still has little power, low compression as one can feel in the kick pedal and also most alarming of all consumes lots of oil, about 1 liter/300km.
    At this point i don't know what to do next, if it is valve rings wear, then mybe we can try getting and fixing them in Amaty, as we are now 900km from it, but if it is cylinder wear we have no choice but to drive it home as it is and complete the oil every 100kms. When we opened it, we could not see any visible signs of wear, and yet, the oil is going away like crazy.
    <!-- controls -->Do you have any idea where could it be from?[​IMG]
    #97
  18. overlandr

    overlandr Dystopist

    Joined:
    Nov 30, 2003
    Oddometer:
    6,021
    Location:
    Sydney
    I think Jerome's on around 140K km but he's on his second engine.:wink:
    #98
  19. gunnerbuck

    gunnerbuck Island Hopper

    Joined:
    Nov 19, 2005
    Oddometer:
    6,634
    Location:
    N.V.I, B.C.
    Is your bore in good shape ? Do the crosshatch hone marks show good in the cylinder? Do any scratches or scoring show on the cylinder wall or piston? Maybe the bore will need a light hone to get the rings to seat....


    I'm nearing 102,000 KM on my 03 640 A and for my engine I have found the valves are quite worn around the 40,000 KM and should be refreshed at that time.. I've had the valves done at 40,000, 80,000 and plan to refresh again at 120,000....
    #99
  20. gunnerbuck

    gunnerbuck Island Hopper

    Joined:
    Nov 19, 2005
    Oddometer:
    6,634
    Location:
    N.V.I, B.C.
    Here is an interesting write up on worn valves:

    Worn Valve Stems and Guides
    When wear has taken place on valve stems and valve guides, the vacuum in the intake manifold will draw oil and oil vapor between the intake valve stems and guides, into the intake manifold and then into the cylinder where it will be burned. If this condition is not corrected when new piston rings are installed, an engine is likely to use more oil than it did before because the new piston rings will increase the vacuum in the intake manifold. When gum or deposits on the valve stems are removed - a procedure recommended when overhauling an engine - the seal previously formed will be removed and leakage will be more pronounced. This is particularly true on overhead valve engines where loss of oil may occur on the exhaust valves as well as on the intake valves. High oil consumption caused by too much valve guide clearance can frequently be cured by reaming or nerraling the valve stem. In some cases new valves may also be required. Use of a permanently bonded valve stem seal will give added insurance against oil leakage on complete engine overhauls or on valve jobs....