Prepping a 640 adventure for a bit of travelling

Discussion in 'Thumpers' started by Umarth, Apr 7, 2013.

  1. Umarth

    Umarth Been here awhile

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    I'm in the last leg of prepping my KTM 640 Adv fora couple of years on the road and as I ramp up the pace on the wrenching, I figure I'll start a thread where I'll post my progress and, more importantly, all the questions that arise as I do this. I'll start by a quick overview of the bike and what's been done so far on it.
    Purchased the bike some time mid-July last summer for this coming trip.

    [​IMG]

    It had 25-30k km on it and the previous owner seemed to be a straight up guy but in the end was full of crap. For instance the bike was repainted after what looks like a peaty hard crash (both lower radior mounts where broken, sub-frame was twisted out of alignment by a good 2in, one of the rear side plastic panels had cracked and been fixed by embedding red-hot screws into it). Does not mean that the PO did not take care of the bike, but if he lied about it's history, may very have lied about his maintenance of it also. So my confidence level dropped and so decided to do a lot more preemptive maintenance on the bike that I had planned.
    Took the bike for a test run (3500 km) around the Cabot trail (Nova Scotia, Canada) just to see how it has on a longish trip. Glad I did as I noticed that I got one of the LC4 that's more of a vibrator than an engine (the girlfriend love's it ), and that the vibes where killing my hands and writs. Also, bikes sprouted leaks on the clutch oil reservoir, the counter sprocket seal, the Speedo gave intermittent readings when in rain and the day after, yadi yada yada...
    So, when December 15 rolled in and by law had to put the bike of the road (fu%^tard quebec gov), this is what happened to it:

    [​IMG]

    At first, when I popped open the engine top end, I was only intending on doing a valve adjustment and rebuilding the water pump. But then curiosity got the better of me and I dug deeper wanting to see what piston, cylinder wall and valves looked like. So this happened:

    [​IMG]

    [​IMG]

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    [​IMG]

    The piston was overall in good shape but the skirts where a bit grooved and, at the prompting of my mechanic, in view of the fact that I'll be putting 100,000km on this thing, I went and put in a new piston.
    So, this is what is looks once I cleaned everything up:

    [​IMG]

    To bad I ended up ditching the piston as I was quite happy with the cleanup (dipped it in pine sol for a few days then used a tooth brush to scrap the goop off). I guess it'll be a spare in case the new one has an "accident" with bad gas...

    [​IMG]

    Then I came upon this little issue:
    [​IMG]
    Looks like the auto-decompression pin is on it's way of being shaved a bit to closely. So went the safe route and replaced that to. My dealer as real nice in seeing why I was changing the whole cam shaft for such a ridiculous thing as a pin, he sold it to me cost, did the same thing for the piston actually!
    (side note: Duroy KTM on the shouth shore of Montreal has been really impressive in the service and even more importantly the fact that they actually stock parts!! Such a change from BMW dealers in Montreal.)
    #1
  2. Umarth

    Umarth Been here awhile

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    So today I finally filled the bike up with fluids and with heart pounding, hit the start button. Only to be disapionted by an engine that turned but simply did not catch and run.

    Fiddled arround with it for an hour, checked if gas was getting to the carb, checked if the spark plug was firiring, check if carb was properly clamped for vacume leaks, even adjusted the spark plug's gap. Nothing! :dog

    So went for a walk in the woods to cool down and, most importantly keep me away from that start button while the battery re-charged...

    When I came back I noticed this odd thing on the handdle bar... You know, the lever that's links to the carb via a steel wire: the choke. F&^%, forgot to put it on! I'll put it on account of being so stressed at the idea of possibly not having put the engine back up properly and waiting for it to explode or more likely, bend a valve stem.

    So attemp 46, or 1 with choke: It's alive!!! Mouahhahahaha!!

    <iframe width="420" height="315" src="http://www.youtube.com/embed/Uv6tO_HaVHo" frameborder="0" allowfullscreen></iframe>

    So after much rejoincing that the engine did not catastrophicaly meltdown and even idled preaty much like it used to last year, I noticed that the engine emits some distincts sounds and that I don't really remember if this is how it use to sound. Mainly, it's the first time that I've adjusted valves before so maybe I did it wrong and the valves are slapping? Or maybe it's normal? What do you, oh lords of the LC4, think?

    <iframe width="420" height="315" src="http://www.youtube.com/embed/8ZrIdoC7uAs" frameborder="0" allowfullscreen></iframe>

    Also, I'm wondering , what the breaking procedure for new rings? Is there one? Should I change the oil after 500km or something?

    thanks guys!
    #2
  3. gunnerbuck

    gunnerbuck Island Hopper

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    I listened to your video and it sounds like a little too much clatter coming from up top, but sometimes video makes things sound worse than they are... To play it safe I would recommend that you recheck the valve clearances... While you have the inspection covers off give the rockers a side to side wiggle to make sure your axial rocker shaft play is not excessive... And if that all checks out go for a long ride to B.C., and stop in for a visit...
    #3
  4. Droptarotter

    Droptarotter Long timer

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    It does sound a little noisy up top.........but not too bad.........I'd take it for a run and then re torque the head and set the valves.

    Cheers
    #4
  5. Umarth

    Umarth Been here awhile

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    Sounds fair,

    I'll ride it a bit Saturday and re-torque and adjust the valves.

    Thanks
    #5
  6. chasbo

    chasbo Long timer

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    +2 Really important. If one of those fails it will be a lot more headaches.
    #6
  7. matalyn

    matalyn n00b

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    Here's what happened to my 640 last saturday when one of those damn rocker failed..
    [​IMG]

    Mata.
    #7
  8. bmwktmbill

    bmwktmbill Traveler

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    Mata,
    That is ugly.
    bill
    #8
  9. Umarth

    Umarth Been here awhile

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    That's gonna cost a pretty penny to replace... :/
    #9
  10. Umarth

    Umarth Been here awhile

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    Woe to me! After the engine rebuild, started without to much drama 2weeks ago: and now stubbornly refuses to even think of starting up and I&#8217;m at my wits end as to what could be the cause...

    Last time I tried to start it, it took a while before it finally did start but that was because I had forgotten to put on the &#8220;choke&#8221;. While trying to get it to start, without the &#8216;choke&#8217;, pressing the start button would turn the motor at a good speed even if it did not properly start. Probably attempted to start the bike some 20 times. A few times leaving my fingur on the start button 5-6 seconds.

    Last weekend, I did a lot of electric work on the bike. Mainly, I added a fuse block in the cockpit area that switches on when the key is turned to the on position. I only ran two wires back to the battery, to feed the new fuse block. All the electrical I did was then stuff that I plugged into this aux fuse block. The electrical took all my available time last week end so did not even try to start the bike.

    And now, we get to yesterday. All happy that the electrical is done, the engine is all done and finally ready to ride and check if all is working properly. Well, didn&#8217;t get very far! Nowhere to be more precise. Hitting the start button would only turn the engine over once then the starter relay starts clicking like crazy.
    So my first thought was that the battery was discharged. Hooked up the battery to the charger and waited to say that it was charged. Same behaviour: engine turns over until it hits TDC. At which point starter relay again starts to click like crazy. Not only that but I have to wait a good minute before I can try again. Otherwise, it does not turn the engine at all: the relay starts clicking immediately.

    Pulled the spark plug out and re-attempted, just to see if it would turn normally without compression: turns like a champ. Also noticed that spark was orange. I was expecting bluish. So i took off the sparkplug boot (?) and freshened up then screw to wire area of the wire that goes o the solenoid. Spark is now blue, but still no go.
    Figured maybe the battery was a dud, so I got the battery from my car and tried that. Exact same behavior.

    Figured maybe I had partially broken a connection/wire somewhere and that the starter was not getting all the juice it needed or was badly grounded. So I bypassed all the electrical of the bike and ran +/- wires directly from starter to the battery. Same thing, as soon as piston is TDC, everything stops.
    All that remained was the starter at that point, so I took it out and disassembled it. Was clean and all appeared fine. Wear on the two &#8216;contacts&#8217; was minimal (a good 2mm left of extra material). Still, cleaned and re-installed. Exact same behavior...

    Note, on all the tests, I tried with and without using the manual decompression lever. Would sometimes let it turn a bit more but usually not.
    So, I&#8217;m stumped!!!

    How come it started 2 weeks ago and now it wont???
    What else could look at? I could bring it to a mechanic but it defeats the purpose of prepping for the trip: not learning anything to get a mechanic to do it for me.
    #10
  11. gunnerbuck

    gunnerbuck Island Hopper

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    Did you try the kickstart?

    I worked on Fastlanes 640 A a while back and it had the same symptoms...
    His bike had a few issues that I could find but the main one was a worn out starter sprague clutch... We replaced that and the bike started right away... The bike would crank over but at a reduced speed while the sprague was slipping... This would give a less than ideal spark...

    It is not unusual for the E-start once in a while to have trouble rolling past TDC on a fresh engine, especially with an older battery... What I do when this happens is use the manual lever to help reduce compression and get the motor spinning... If your bike is doing this every time and you have proven the battery to be good then something is not right... Either your auto decomp is not working or you are losing voltage that should be going to the starter... I assume your valves clearances are correctly set?
    #11
  12. Umarth

    Umarth Been here awhile

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    So a possibility would be that the starter Sprague clutch is worn and with the new rings it's no longer able to go passed TDC? I could test that by pulling the manual-lever during the start process?

    Speaking of which, what exactly is the procedure to use the manual-decomp lever? Do I pull it in that the way until the engine starts? or should I only partially pull it?

    The auto-decomp not working? that would be a bitch: I just replaced the cam-shaft so I would expect it to be working. How would I go about checking if it works? I know about the "clacking" sound but can't really say that I hear it. If I take off the rocker cover, what would I look?
    #12
  13. gunnerbuck

    gunnerbuck Island Hopper

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    To start using the manual decomp, just hold the lever in to get the engine spinning and then let it go... To kickstart set the engine just past tdc { just slightly past the point where the kickstart becomes hard to move} and give it a good kick ...


    When you roll the engine around manually you should here the auto decomp klack as the engine turns...

    When the engine is running if you turn the idle down below 1400 you should start to here the decomp clatter...
    #13
  14. Umarth

    Umarth Been here awhile

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    thanks, i'll try that out.

    here's me crossing my fingers...
    #14
  15. Kawidad

    Kawidad Long timer

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    It could still be the battery. A dead cell will still register 12v. Put a voltmeter to the battery and then crank the starter motor and look at the voltage reading. If it drops dramatically, then the battery is toast. It should maintain its voltage readings even while cranking the engine over. :deal
    #15
  16. Umarth

    Umarth Been here awhile

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    What would be considered as an unacceptable voltage drop? 11v? 8v?
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  17. Kawidad

    Kawidad Long timer

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    Yes to both. It should maintain around 12v when starting. It should read around 14v when static or running and charging. I know it's a 12v battery, but they should read higher in the above conditions. I'm not an electrical expert, just learned the hard way. :freaky
    #17
  18. Umarth

    Umarth Been here awhile

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    Looks like might very well have been the issue!
    When I used the car battery I wasn't very confident about the jumper cables I used but did't take the time to check them out. Well, I went back and tested them for continuity and it looks like the negative cable is broken and offers infinite restance.

    So I made a set of jumper cables using 220v house heating wires and re-attempted it with the car battery. Engine started right up! Hopefully I can get my hands on a new battery this week and I can validate that that's that.

    Quite happy to see that I did not f'up something during reassembly...:freaky


    now, during my trying to figure out why it would not start and reading possible solutions on this site, I have two questions that I'd really like an answer to:
    1. What exactly does the starter Sprague clutch do? What's it purpose?
    2. I get how the manual decomp works, but I can't say the same for the auto-decomp. How does it do it's work. And more importantly, how could it fail to do it??
    #18
  19. clintnz

    clintnz Trans-Global Chook Chaser

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    1. It lets the starter gear drive the crank when starting & disengages when not starting.

    There's some little pawls that throw out against a spring to engage on the back of the rotor on the crank. Common setup on a lot of bikes & a common thing to wear out on a lot of bikes. The 640's one often wears out at around the 50k km mark. But you have a kickstarter so it ain't a big deal.

    2. At low revs the thin cam that fits over the top of that worn pin in your earlier pic of your camshaft engages & opens the valves so you or the starter have less compression to work against. With the pin worn it doesn't work so well but you have a manual decomp also so just pull that in, get 'er spinnin then let it out, no big deal.

    Cheers
    Clint
    #19
  20. Umarth

    Umarth Been here awhile

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    Cristal clear explanation! Brilliant!
    Thanks!!
    #20