KTM 640 - engine randomly dies

[Boon Booni]

Originally Posted by Queen of Spades

Update - got the switch back together last week with a light coat of di-electric grease on the internal connector plates (after first lightly cleaning them with a metal scotch brite pad).


Findings tonight:

Before turning the bike over, I connected my multimeter red terminal to the blue/white female connector, and the mm black terminal to the battery NEG post. I read 11.x volts, whether the key was on or not. (?)

I reconnected the blue/white connector at the coil, then started the bike up - it ran for maybe 10 seconds before dying. Confirmed no spark by using a timing induction light.

Disconnected blue/white at coil, and repeated first test above. This time it read ~50 mv or so. I also noticed a distinct whine coming from the area of the CDI (on the left side near the battery). This whine was not audible when I performed the first test.

Is this whining noise normal? Could it be related to the drop in voltage at the blue/white wire?

If you've got 12volts at the coil then our bikes have different ignition systems.


The whining noise sounds like "flyback" which Luke describes in the thread you linked as "very faint whining sound like a tube TV"

I see you responded to that thread, but the OP of the thread hasn't been back to ADV since 12-23-2010, so you might not get any reply.


Seems like Luke's reply is a good for some areas to check.

http://www.advrider.com/forums/showp...51&postcount=8

[Queen of Spades]

I remember seeing a red or orange looking wire going into the CDI. Tried to trace it back just by observation and couldn't find the other end. It was cold in the shop and fresh-baked chocolate cookies were calling.

I have a wiring diagram but I noticed some inconsistencies with my harness and what's on the diagram. I don't know if it's allowable to post that diagram - read the concerns from the mods about posting service manuals.

[Queen of Spades]

Cross referencing another interesting thread, similar problem as mine.

From 2006: LC4 CDI issues?

In reply #9, bigtators wrote,

My 99 LC4E died a while back. I suspected the CDI unit since it was making a buzzing noise when the key was turned to the 'run' position, and some members here and KTM said that it should not buzz. I went through the cheap stuff first, and eventually ran through the electrical system check a few times. Everything met spec, so I bought a new CDI unit. Installed it, put in some fresh gas, cleaned the spark plug and it fired up. From what I gather from KTM, unless your local shop has a test bench (mine laughed when I asked), the only way to check the CDI is replacing it (or finding a buddy with a compatible model/year who'll let you borrow it). Per KTM, the CDI is a non-refundable item, and a bit pricey, so make sure you rule out the cheap/free/troubleshootable stuff first. Good luck!

Another cross-reference, a post by CountPackMan also from '06:

Not necessarily. I got a hell of a spark kicking it over, as a friend of mine will never forget, but it was not sparking regularly. Thats why the bike would run very poorly, especialy at RPMs over 4000 for me. Here is a more complete story:

I was riding the bike in Japan and was heading to Toyama to take the boat over to Vladivostok in Russia when the bike started becoming choppy on the throttle. I thought I was running out of fuel, but it wasn't it. As I went on it felt more and more like the choke was on. I got to Toyama all right though, loaded it on the boat, and forgot about it for the next few days. When I finally got my bike out of Russian customs, it was VERY hard to get it started and keep alive, but since I only drove it about 3 miles from the port before parking it that evening, I was hoping it would all go away after some partying and vodka. Next afternoon I was going to go for a one hour bike ride to a remote beach with a large group of bikers from Vladivostok, but my bike had the same symptoms. I stopped about 5 miles outside of town to fill up the tank. I couldn't get it restarted. Nothing I did would get it to run. Electric, kick, pushinig, long downhills (I have the clutch lever saftey switch shorted off)... I took the tank off. A Japanese friend had the genius notion of holding the spark plug with his bare hands (and not by the rubber wire either) while I kicked it. Hilarity ensued

We definetly had spark. We couldn't figure it out and by now it was night, so I left my bike with a nearby factory gate guard for the night and picked it up the following morning with a truck and took it to a repair shop. Their diagnosis: CDI. It took over 2 weeks for a new one to arrive and Russian customs raped me . When it finally did arrive, we just put the new one in and it fired right up and rode perfect. That was over 30,000 miles ago.

If you're replacing it anyway, you might as well upgrade to the switchable octane version.

[gunnerbuck]

Originally Posted by Queen of Spades

Update - got the switch back together last week with a light coat of di-electric grease on the internal connector plates (after first lightly cleaning them with a metal scotch brite pad).


Findings tonight:

Before turning the bike over, I connected my multimeter red terminal to the blue/white female connector, and the mm black terminal to the battery NEG post. I read 11.x volts, whether the key was on or not. (?)

I reconnected the blue/white connector at the coil, then started the bike up - it ran for maybe 10 seconds before dying. Confirmed no spark by using a timing induction light.

Disconnected blue/white at coil, and repeated first test above. This time it read ~50 mv or so. I also noticed a distinct whine coming from the area of the CDI (on the left side near the battery). This whine was not audible when I performed the first test.

Is this whining noise normal? Could it be related to the drop in voltage at the blue/white wire?

You have to be careful when testing wires around the CDI, it is not unheard to fry the thing and they are quite expensive to replace...

A few pages back I mentioned for you to visually inspect the stator and pickup coil, have you done that? I have seen more than a few times where the stator/ pickup running surfaces were scored up and gave intermittent electrical problems similar to what you have been describing...

It is very easy to remove the stator/cover { 4 bolts} and if your careful you may get away with reusing the gasket... You'll have to remove the counter sprocket cover as well...

[Queen of Spades]

Another clue by CountPacMan:

It shouldn't be buzzing. The CDI is all solid state electronics...

[Queen of Spades]

Originally Posted by gunnerbuck

You have to be careful when testing wires around the CDI, it is not unheard to fry the thing and they are quite expensive to replace...

A few pages back I mentioned for you to visually inspect the stator and pickup coil, have you done that? I have seen more than a few times where the stator/ pickup running surfaces were scored up and gave intermittent electrical problems similar to what you have been describing...

It is very easy to remove the stator/cover { 4 bolts} and if your careful you may get away with reusing the gasket... You'll have to remove the counter sprocket cover as well...

Gunner, is the stator in oil? Do I need to drain it first?

[Queen of Spades]

And this from bigtators:

Here's the last bit of info I think I will squeeze out of this experience:

Finally came across the old CDI unit in one of the boxes from my move. Went ahead and installed it in place of the new unit to see if it would work. It started buzzing when I turned on the ignition, and bike would not start. Reinstalled the new unit, no buzzing, and it fired right up. So... if the CDI unit itself is buzzing, then it may be on its last legs.

[gunnerbuck]

Originally Posted by Queen of Spades

Gunner, is the stator in oil? Do I need to drain it first?

There is not much oil in the stator chamber... I usually lay the bike over a bit propping it up at 45 degrees with a couple of blocks, then no oil leaks out...

It is possible that in your poking and prodding with the tester you may of fried your CDI , hopefully not...

[Queen of Spades]

Never tested resistance or voltage on any of the CDI wires. The symptoms haven't changed before I even did any of that.

[Boon Booni]

Originally Posted by Queen of Spades

Cross referencing another interesting thread, similar problem as mine.

From 2006: LC4 CDI issues?

In reply #9, bigtators wrote,


Another cross-reference, a post by CountPackMan also from '06:

Sounds like a possibility... Though $201.55 is quite a bit of a guess...

EDIT.. $181.58 for your bike. Neither one as bad as I would have thought actually.

[Queen of Spades]

Originally Posted by Boon Booni

Sounds like a possibility... Though $201.55 is quite a bit of a guess...

EDIT.. $181.58 for your bike. Neither one as bad as I would have thought actually.

If that is what's going on I'll be getting two of them, one to keep as a spare.

Next thing I will check out is the start/stop switch.

Where did you find a CDI for $181.58?

I'm showing KTMWorld listing it as

58439031000

DIGITAL BOX CDI

359.82

[Queen of Spades]

Found it on KTM Parts House at $182

DIGITALBX CDI CB7459 95ROZ'99 58439031200 (replaces 58439031000)

1

$181.58

Will hold off ordering until I am positive nothing else is causing the problem.

I'm beginning to wonder if the loose wires from reply #17 this thread didn't cause the CDI to malfunction.

[Boon Booni]

Originally Posted by Queen of Spades

Found it on KTM Parts House at $182



Will hold off ordering until I am positive nothing else is causing the problem.

I'm beginning to wonder if the loose wires from reply #17 this thread didn't cause the CDI to malfunction.

Yep, that's the place. I've ordered $300 in bits a pieces from them over the last few months.

[Queen of Spades]

Update:
I placed an order for a replacement/spare CDI with KTM Parts House. I haven't ruled out other problems (see further below) but ran into trouble getting a headlight switch last year (discontinued for the 99 model). This machine is getting some age on it, and I don't want to run into a similar problem with a CDI. Also ordered a spare start/stop switch for the same reason, since I've read that part has been associated with failures on some LC4's. I should probably get a spare pulsar coil for the same reason.

Having said all that, check the response from KTMPartshouse regarding updated CDI part number and price:

I received your KTMpartshouse.com order. The first part you’ve requested (p/n 58439031200) supersedes to another part number which would be 58639031644, this part actually costs $236.24 off of our website.

I ordered two new 6 pin Molex connectors to fix some existing wiring hacks from previous owner (looks like they hooked up a different headlight at some point, then put the stocker back on). Got the .093 molex pin tool, too.

While I have the top end exposed I'm going to check valve clearances and adjust as needed. Motion Pro feeler gauges arrived last week. Have two cover gaskets on the way.


Next Steps:
Plan is to check my current stop/stop switch for resistance and make sure that is working properly.
Will pull the generator cover (per post above) and make sure there isn't any damage there.
Finally, will go through the existing wiring with a fine tooth comb, organizing and zip-tying/taping where needed.

[Queen of Spades]

Trouble with a Molex .093 connector. I removed the male pins out with a .093 extraction tool, but the female pins appear to be the same size as the tool I have.

Anyone know what size tool I need to get the female pins out?

EDIT: Called Molex directly, they say that the extraction tool should remove both male and female pins in the connector housings. The tool I bought was a cheapy, they recommended their own tool, which I've since ordered.