KTM 640 supermoto spark problem PLEASE HELP!!!

[BradB]

hello!

i bought a KTM 640 lc4 supermoto about 4 weeks ago, all was good, bikes runs mint!

then out of the blue, the bike dies while riding in second gear, no warning or nothing! totaly dies!

so i took it home, checked the plugs, no spark!

so i tested the coils, nothing to the coils,

i checked the cable that connects the ecu to the coils, think its a blue wire, and theres a constant live,

now this is the weird bit...... when i plugged the wire back in, the spark plug sparked when the ignition was on, and the connector sparked, so..... the coil must be working to creat a spark, and theres a charge beeing created enough to spark the plug when the engine isnt being turned over.


after putting the wire from the acu back onto the coil, i got a spark at the plugs when engine turned... put plugs back in the engine started!!!


put the plastics on, started it, and nothing!!!


now the same as before, geting a spark when i connect the ecu/cdi to the coil but no pulse when i turn the engine over.

now i know that this is the wire to the coil, as when it decided it was going to work as mentioned earlyer, i tested it with the timing/spark tester, and was showing there was a good pulse coming from the ecu box before getting to the coil, then when it failed the second time i tested it nothing, just a little voltage constant feed when it should be pulsing



any ideas what this could be???


would it be the ecu/cdi??? or would it be the pulser pickup coil on the fly wheel??

im stuck, annoyed, and havnt got a clue what to do, i got a new ecu/cdi unit coming, a new coil coming, and a new switch gear as i did find a fault on that, it was a bit temprimental.


hope someone can help me!!!





regards

Brad

[bajadog]

Brad,

The part about putting the plastics on, and then it not working almost
sounds like you knocked a connection loose somewhere.

If you don't mind, let me pose your dilemma to some others more
enlightened than me on ignition issues.

Marco

[BradB]

well thats what i thought at first, but then when i took everything off again, unplugged the ecu wire from coil to ecu, and put it back in a few times, i got a spark again? and bike started, i turned ignition off, put plastics on and same again, and now i cant get it running at all


so i have a funny feeling it might be the coil pick up sensor on the fly wheel? as when i connect the wires from ecu to coil i get a good *1* spark everytime i do it withought turning engine over, which tells me the coils are working, the power is working to make the spark, but maybe the pick up coil from the flywheel isnt working?

i could be wrong but the more i think about it, the more it makes sence, as for each time the fly wheel turns, the sensor picks it up and send a signal to the ecu to spark the plug? kinda working like the timing. so if this is failed i wont get a spark at all? coz its not recognising the engine to be turning, so not needing to spark??


im going to buy a eletrical test kit in the next few days, get the owners manual out, and see what readings im suppose to get from the pick up

maybe this is a good idea?

someone told me they had the same problem with the exact same bike, they had to change the full wiring loom, and that fixed the problem,

but i realy dont want to do that, and it seems the exspensive way round it :/ and ive only had the bike 4 weeks, i bought it private


cheers for your help so far!! and i look forward to hearing from u!

[Dmitry]

If you swapping parts I suggest start with CDI box, the fact that you get a spark every time you connect things tells me that there is problem somewhere between CDI and wiring.

Pretty sure that on your bike coil is always "hot" and CDI controls ground pulse so when you hook up the coil and get a single spark that means you have ground, not likely they designed it that way cause then if you turn ignition on with engine not running you are cooking the coil and CDI. I would check the ground wire from CDI to coil, probably chafed and grounded somewhere.

[BradB]

the coil is grounded to the frame, lol so it only has one input lead to the coil, and the other end of the coil is earthed, same with the ecu/cdi unit, has a big dirty earth on it lol, all checked, and seem to be ok, ive also cleaned every single connector i can find on the bike, and used WD40 on them all, :/ thats why i thought it might be iether a CDI problem, or a pick up coil problem, just have a real funny feeling its the pick up coil sensor :/
so im ordering one off ebay, but they arnt cheap!! i can get everything else prety cheap, but the sensor is hard to get hold off. and it pricey,


im also getting a new wiring loom thats been tested, so if worse comes to worse ill just get the wiring loom fitted, will save trying to find a bad wire if all else fails


totaly gutted its not working though!!

i hope i get her working, only had her 4 weeks, and miss playing on my toy

[bajadog]

Brad,

Here is a post the was addressing your issue from another forum:

"I had a similar problem with my Duke ll - intermittently no spark at startup - turned out to be loose contact inside (not outside to the unit, but inside) the Voltage Regulator. Replaced it with a cheaper universal regulator – works 100%. Hope this helps. "

[BradB]

ok...
so i tested the pulser coil pickup today, and got a 0 reading!
on my eletrical tester, it has ohms, in 20,000k 2000k 200k 20k 2k and 200

so i put the dial to 200 ohms, and tested the wires directly from the pulser coil and got nothing, i got nothing on volts, or amps or any other reading the eletrical tester does!


so im guessing the pulser coil pickup is dead!

fingers crossed this is the problem! ive ordered another one, so lets see what happens

any ideas of what the reading should be from the pulser coil pick up??

i read somewhere it should be about 80-120 ohms??

if im getting a dead 0... then is this the problem??


cheers guys for all your help so far!