mcliberated’s 2002 520 exc thread

Discussion in 'Thumpers' started by mcliberated, May 26, 2019.

  1. mcliberated

    mcliberated Adventurer

    Joined:
    May 17, 2019
    Oddometer:
    41
    Location:
    Denver, CO
    Here’s my first KTM! $1800 with ? miles, no service records, and some odd sounds and leaks. No worries!
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    I took highway 105 from Monument to Salida, then to Denver. No turn signals on i25 is a little scary-I just tried to pretend that I was someone who naturally doesn’t use them and that worked. Also used hand signals.

    Leaky things:
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    water pump seal kit ordered.

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    leak from the lower screen bolt which is all but stripped. Jb weld, threads and KTMtalk.com, and a BRP plug replacement to the rescue.
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    weird fuel system with a kink in it, will be re-doing this:

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    The telltale signs of the valve adjustments are there, so that will be happening a long with everything else. There is also a clacking coming from the bike at low revs which I believe is the auto- decompression thing in the cam wheel. Although this is an ‘02, I’m worried it has the nylock nut and I’ll be checking that out too at some point.

    Other things:
    Rear brake bleed
    Oil change

    Then taking her up to the trails and passes in the rockies with some members here. I reached out and already have a couple potential riding buddies! Love this forum! Any ktm suggestions welcome as I’m a total n00b!
    #1
  2. mcliberated

    mcliberated Adventurer

    Joined:
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    Oddometer:
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    bike came with: barkbusters, acerbis 3.2 gal tank, trail tech endurance computer, cam bearings replaced and output shaft nut re-tightened.
    #2
  3. mcliberated

    mcliberated Adventurer

    Joined:
    May 17, 2019
    Oddometer:
    41
    Location:
    Denver, CO
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    scary looking screens, nasty oil ^^

    Bled brakes with 5.1 fluid, reset valve clearances, new spark plug, found chunks of gasket and a couple metal flakes in the screens but none in the filters, changed filters. put the brap plug in the lower screen plug. Re-did my water pump seals which the previous owner put in backwards, but i’m still getting a lot of oil from the weep hole every time i pin the throttle, so i’ve done it like 3 times, only to dig through thumpertalk forums and find out the two o rings that came with the thumper kit are the same size and thats why it’s not seating or sealing well. Having taken the carrier on and off a lot now, I think I just need a new kit. I’m calling to see what they can do to help since they sent me the wrong stuff.
    #3
  4. mcliberated

    mcliberated Adventurer

    Joined:
    May 17, 2019
    Oddometer:
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    Location:
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    got these two riding on my trip back to wisconsin, got to ride through green fields at my parents’ place! Had to rebuild the mikuni carb on the dt, slide was stuck open=full revs upon start up. the throttle cable was to blame, zip ties to the rescue and we were off!
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    me on the yz80 at around 7 yo

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    #4
  5. mcliberated

    mcliberated Adventurer

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    well I took both o rings off and it looks like it was user error. The seal was pinched and even caused some light brushing on the o ring holder. I went to G force parts store in Denver and they had both o rings in stock. Re installed and just waiting a good while for the locktite 515 to dry with the bike tipped away from the seal. It felt like it popped into place and I didn’t have to push as hard to get the full insertion :jjen

    On the kickstand, the bike leaning causes a small amount of oil to come from behind the cam bearing and through the (hopefully no longer) leaking inner o ring seal. There is oil weeping under my oil filters, but I’m leak testing once I can go ride.
    #5
  6. GSXR

    GSXR Trail Rider

    Joined:
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    Location:
    Sunshine Coast, Australia
    Wow, that's definitely a scary oil screen McL. Don't ride too far from home before re-checking it
    #6
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  7. RideFreak

    RideFreak Torque Jockey

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    I'd be leery of those rides down I-25, it's going to accelerate the rebuild you've got ahead of you.
    #7
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  8. mcliberated

    mcliberated Adventurer

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    yep, trying to get some fun rides in before that happens. sloppy gasket sealing is why the screens are so mucked up. (found the locations of the green, black, and white stuff)

    RF-I have to ride at least 35-45 miles to get to any ohv/gravel roads, will be taking back roads mainly to avoid anything north of 65 mph. I’m going to putz around tomorrow and see if the oil still leaks, if not, off to gross reservoir to ride a little gravel.

    rebuild- I know it’s imminent but I’m curious just how far....how much is a leak down these days?
    #8
  9. RideFreak

    RideFreak Torque Jockey

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    Depends on the shop, a good independant shop will likely save you some $$ but a leakdown isn't really the issue, you know it's going to have to eventually come apart. When the time comes the money might be better spent evaluating the engine components when it comes apart. You've got brass and alum flakes, could be something as simple as a cam chain guide for the alum pieces but the brass pieces would concern me a bit more. Bearing cages and thrust washer material usually cause the gold flakes and tend to be more expensive to fix.
    #9
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  10. mcliberated

    mcliberated Adventurer

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    big aluminum flakes, small gold flakes. Also, that fucking waterpump still leaks oil from the weep hole after the 4th change with new o rings. it’s a shame, this thing hauls ass but I’ve only had it on a few short rides because of the oil leaking and the revelations of what my oil looks like after ~10 15 minute rides. My budget for this thing this month is toast, so now I am just going to save for a few months and send the engine in for an inspection and rebuild. In 2k so far bike included. kind of like 2k for a cool bike that can’t take me very far and now will sit for ~6 months. I can remove the engine myself and ship it so that should save some $$$.

    Probably wont ride much this season which is the biggest downside. A82490F1-B7E9-4460-BDE8-65F0F840D8B8.jpeg
    #10
  11. RideFreak

    RideFreak Torque Jockey

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    Sounds like the cam is grooved where the seals ride.
    #11
  12. mcliberated

    mcliberated Adventurer

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    Thanks RF! I emailed Travis and that’s the baseline for my rebuild quotes. Any one have an rfs laying around? :pope
    #12
  13. mcliberated

    mcliberated Adventurer

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    Alright folks, so thats silver ferrous metal shavings and brass from the short screen under the crank, clean oil from the long screen, and some ferrous, tiny metal deposits on the drain plug.

    waterpump oil leak: the cam shaft seems smooth. I’m miffed. visible wear, but no indentation at all to the touch where the seals ride.

    Attached Files:

    #13
  14. RideFreak

    RideFreak Torque Jockey

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    Then you might need the seal assy that Thumper Racing sells, it's a replacement alum piece with the seals already installed, your seal housing might be damaged. Also you want to tape the end of the crank before you slide the seal housing on. One layer of electrical tape extending past the end of the crank, it's used as a seal bullet to prevent damaging the seal as you slide the seals over the end of the crank, same principle as the seal bullets for the fork seals.
    #14
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  15. mcliberated

    mcliberated Adventurer

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    I love seeing that “your brilliant reply” before I type something stupid: I bought the thumper kit but because of o ring pinching and folding and redoing the job 4 times, I’m afraid I might have worn out the new carrier’s seal by sliding it on and off (although I used that bullet sleeve included for taking it on and off).

    I bought 2 new o rings from a dealer just to be safe the last time and used the 515 sealant (light coating). everything was prepped and smooth. Popped in perfectly, still leaking.
    #15
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  16. mcliberated

    mcliberated Adventurer

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    have 1 quote in for rebuilding the crankshaft, at this price I may buy a used bottom end and swap
    #16
  17. RideFreak

    RideFreak Torque Jockey

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    That's the problem, by the time you go through the motor, fix the crank, possibly a new top end it's likely you'll have spent allot of cash on top of the purchase price. There's no guarantee a replacement bottom end is going to be much better than yours unless it's been rebuilt already, those flakes aren't uncommon in a high mileage RFS. You should join KTMTalk and keep an eye out on the RFS thread and the big bike partout thread. It's a good resource if you decide to freshen it up.
    #17
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  18. mcliberated

    mcliberated Adventurer

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    Dug through there, just put up a post to get some input there too. I agree about the lower end swap; the only rec for that 400 exc lower end was to do Travis’s 453 kit and use my top end, but cost wise it ends up neck and neck with a totally rebuilt top and bottom oem 510cc engine, so i’m going to save up and send it to docbob or djh to get the cyclinder replated and everything redone. I rolled the dice on this bike, now it’s going to sit for a long time while I save up to pay the price, but with proper maintenance a rebuilt engine from one of these master tech’s is going to outlast me.
    #18
  19. ohgood

    ohgood Just givver tha berries !!!

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    i wouldn't even start that engine again. the con rod will be a lot more artificer as it is right now, than sticking out of the cases !
    #19
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  20. mcliberated

    mcliberated Adventurer

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    Haha! I can’t wait for this turd to shine once the engine is rebuilt. Thanks for the advice!
    #20
    ohgood likes this.