KTM 640 Adventure owners, sign in please...

Discussion in 'Thumpers' started by creeper, Feb 20, 2004.

  1. clintnz

    clintnz Trans-Global Chook Chaser

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    The 640A is a physically bigger machine than the DR650, so what will suit best may depend on how tall you are. The KTM is not really any heavier though. The KTM suspension is in a different league. The 640 has a more vibey motor than the DR, but makes more power with similar fuel consumption. Maintenance is much the same although the oil in frame 640 takes a few minutes longer to do a service on. 640 motor needs a cam bearing/water pump service at about 40K km then should do that again before needing much else if well cared for. The KTM has a much stronger main frame vs the DR but you'll need to reinforce the subframe if you're riding hard with a big load.

    They still make DR650s but the 640 line shut down 11 years ago, just recently some 640 parts have been getting hard to find so the Suzuki wins on parts availability. Obviously there's great aftermarket support for the DR but most of that is fixing stuff that was done right on the 640 from the factory.

    Cheers
    Clint
  2. timeOday

    timeOday Long timer

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    The surest sign is if you work really hard and finally find something "In Stock" somewhere, it probably isn't really.
    albacore and Whodatschrome like this.
  3. mikelduke

    mikelduke n00b

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    First of all, sorry for quoting such a long time ago response...

    I have a high flow 04' duke, and I want to install an FCR41. Because of the increased cylinder filling (I also will open up the air box), will I have to decrease ignition advance at high rpm and high throttle at my ignitech map? I think factory setting is 38 deg

    Thanks a lot!!
  4. NitroAcres

    NitroAcres MotoBiggots Suck Supporter

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    I have FCR41 on my SXC...full LeoVince Exhaust and no Snorkel ...it seems to run fine...and has for many thousands of miles.

    I have always been at a loss as to MotoLabs claim to "Extra Cylinder Filling"...as the cylinder draws in a specific volume of air/fuel..and is limited to that volume by cylinder size, stroke and cam timing...

    Now you can alter the mixture of what that cylinder is Filled With..and yes a BST or FCR will change that..as will a restrictive intake or exhaust, along with ignition timing..Tuning those is the trick..but it isn't exactly rocket surgery ..
  5. twqqis

    twqqis Adventurer

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    Hi Clint,
    Always appreciate your knowledgeable input.

    I've been wondering for a while if I should be keeping an eye open for parts and grabbing where possible... You mention some parts becoming more difficult to find, could you list them (or is that already a long list)?
  6. clintnz

    clintnz Trans-Global Chook Chaser

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    I think what Derek means is that there is less pressure drop on the intake side, so the same volume at higher pressure = more stuff in the cylinder. I have a TM40 flatslide waiting for a rainy weekend to fit up so it would be interesting to know the difference in timing between the LC4 E/Adv & the SXC. I'm not getting too stressed however as a mate has put many miles on his 04 LC4-E with an FCR39 & no problems. More of a concern on the pre high flow bikes I think.

    All anecdotal from my side, everything I've ordered from the local dealer lately has turned up eventually, but people have definitely had trouble finding the wear prone lower rear shock bushing.

    Cheers
    Clint
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  7. NitroAcres

    NitroAcres MotoBiggots Suck Supporter

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    My 2000 ADV has an FCR39 also open top airbox and a non restrictive Shopbuilt/LeoVince exhaust.. also many thousands of miles on it..zero issues..

    As far as the "pressure drop" theory.. it is still just a normaly asperated engine.. limited to what atmospheric conditions exist... right?
    One of my largest concerns is the air filter is the same one for a 65cc twostroke, hard to believe it breathes enough for the BigBore Single too.. :)
  8. skibum69

    skibum69 slave to gravity Super Supporter

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    Mine is still skipping a bit so now I have to order the new flywheel and it’s been backordered at Munn and KTMWorld for months.
  9. meat popsicle

    meat popsicle Ignostic

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    My 2003 (hi-flow) always had the BST40; still does. I opened up the side airbox cover the same amount as the KTM part (small opening); snorkel left in place. I ran with the Supercrapp for about half of the years since I got the bike new in 2004; the other half was with a Staintune can with dB eater installed.

    Derek warned me at the time to reconsider using the dB eater as it could interfere with cylinder emptying. I thought "bah" at the time because, well I didn't know that the LC4 is setup from the factory on the edge of stability and any change from stock can unbalance cylinder filling & emptying. What does that mean?

    I think it means that if intake restrictions change the amount of air the cylinder can suck in changes; likewise if exhaust restrictions change the amount of air the cylinder can compress out changes. Why does this matter?

    I think it matters because the amount of air that gets in alters the ratio of air:fuel (and then running hotter or cooler), and the amount of air that gets out influences cylinder cooling (exhaust takes heat with it, amount depending). I think in my case the dB eater increased back pressure on the engine, reducing cylinder cooling.

    Poor cylinder cooling can lead to hot spots forming that can cause detonation - not nice engineered combustion "flame fronts" but little localized explosions that eventually (after 7,000 miles in my case) start destroying stuff.

    Don't take my word for it, ask the old folks who used to comb thru Sommer KTM catalogs (drooling) and noticed they did their own testing (dyno) with mods and said things like "don't remove the snorkel".

    Seeing is believing? OK, here's my 03 LC4's piston after around 20,000 miles (now attached).
    LC4 piston.jpg

    NOTE: everything under the valve cover looked cherry - you won't see the impact of detonation until you open the cylinder. Cylinder scarred, combustion chamber crown scarred to death, bottom end possibly out of true, basically a tosser. I found a used LC4 in good shape and am replacing this one. :\

    OK here's the bottom of my top end (also attached)
    LC4 chamber.jpg
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  10. NitroAcres

    NitroAcres MotoBiggots Suck Supporter

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    Engine modifications and tuning is always a complete package, I typically make the mistake of assuming that people who make modifications understand what they are doing...I know, I know..I shouldn't.
    My Dad was an aircraft mechanic in the USAF, I grew up working on everything, and still do, It is fun.

    DrDerek beat the "Detonation" dead horse one too many times for me...it is an ICE...not the space shuttle..or the X-60A.

    I do however miss his informative posts about BST Tuning..
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  11. timeOday

    timeOday Long timer

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    I can't see the photos
  12. skibum69

    skibum69 slave to gravity Super Supporter

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    Same...no photos
  13. joe cool

    joe cool Long timer Supporter

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    I want to see also.
    Thanks
  14. meat popsicle

    meat popsicle Ignostic

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    fixed.
  15. meat popsicle

    meat popsicle Ignostic

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    That's what Derek always preached: mods require tuning, and by tuning he meant dyno runs with an exhaust gas analyzer. If the NOx go outa whack that's your warning that combustion is not happening properly. What people need to realize that their LC4 (or other Hi Performance single from Europe) is tuned to the edge of stability. Minor changes (like a dB eater or pulling the snorkel) can upset the balance, and cause improper combustion (aka detonation), and lead to quick damage or eventual death.

    Of course if he was still here he would probably jump on and fix my poor recollection, but that would have been a good thing. I think he really cared about this issue and wanted to make sure people found out the easy way (someone harping on them) rather than than the hard way (ordering a used LC4 from the other side of the world).

    That's about all I can help on this issue. I'm more of a bad example than a savior.
    mistakes.jpg
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  16. timeOday

    timeOday Long timer

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    Dayumm, that piston gave its all.
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  17. 2 SPOT

    2 SPOT bring the rape whistle

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    that sucks meat.
  18. meat popsicle

    meat popsicle Ignostic

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    Yeah, but I'll have to agree with timeOday - the LC4 gave it its all. Although it did die shortly after midnight on my way home, it was only a few miles from home. It didn't die in Baja or any of the other remote areas I've rode thru with this going on.

    For a catastrophic failure it was surprisingly gentle (just died at a stoplight and wouldn't start) and timely. And the root of the sucketh was me, deciding to change the intake/exhaust without checking the impact on combustion.

    dB eater is not going back on. I have cut the extended tube off of it and reattached my sparkie. I could also go back to stock side airbox. Pondering if that's enough to not need a dyno with EGA.
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  19. 2 SPOT

    2 SPOT bring the rape whistle

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    well if its worth anything, when i sold my 03 it had 35k on the clock, i had an open slip on muffler, no snorkel and carb tune with no other mods, stock engine and intake system otherwise,,, at about 25k my cam follower bearing went, so i did a topend refresh, was going to do a hone and rings but the piston and cylinder looked great, still had crosshatch on the walls.
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  20. Antti

    Antti Been here awhile

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    Is there any bolt-on knock sensor systems for reasonable pricing available?