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Old 01-13-2005, 03:08 PM   #9
KTM 640 Adventure abuser
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Joined: May 2004
Location: Portland, OR - USA / Oltenita, ROMANIA
Oddometer: 104
Cool2 The (hopfully) definitive KTM CDI guide

ok, a few corrections to my original post have been made(thanks everyone for pointing out my errors!) - namely to the 2002-2004 models with which I got the connection backwards. As I said, I have a 2000 and am more familiar with that, so that original info was correct.

The 2003(and maybe 2002 and 2001? somebody with a 2001 should check on this for me) through current models have a CDI with two ignition curves. The default is for 95 RON and the other is for 80 RON. In Mexico, where you said you were going, the octane is measured in RON (Research Octane Number) as it is in most of the world. In the USA we use (RON+MON)/2 so this is the average of RON and MON(Motor Octane Number). These numbers vary about 10 so a RON of 95 is about the same as a MON of around 85. So in the USA an octane rating of 91 is equivalent to 95 RON.

Somebody correct me if I'm wrong, but I think the CDI just sends signal to spark a little earlier when switched to the 80 RON mode preventing pre-ignition when using low octane fuel. On the 2003 - current models, KTM used the new Kokusan CDI, KTM part number 584.39.031.500. I think they used this for all electric-start KTMs from 2003 - current regardless of model.

How to guide for the 2003 - 2004 LC4 Adventure:

Turn OFF your bike all the way - no lights, no instruments, etc...

Remove the right side plastic panel(opposite the exhaust!) and you will see a black box straped with a thick black rubber band. This is the CDI. There is a mess of wires heading out of this thing to the wiring harness. Find a black and brown wire connected with a nifty socket thingy(keep digging through the wires until you find it! Sometimes they are tucked well out of the way.) When they are connected like this, this triggers the 95 octane setting (default). Now DISCONNECT the wires by disconnecting the socket thingy. This just breaks a circuit and will tell the CDI that you are not in Kansas anymore and to take it easy on the engine - 80 RON mode! Tuck the wires back together out of the way(make sure that the DISCONNECT you made stays DISCONNECTED), put the plastic panel back on, start the bike, and go for a ride. You should feel a slight difference - it feels a bit lacking in power especially on the top end, but its nothing drastic. When on the 80 RON mode your fuel economy will suffer a bit as well. You can go back and forth between these two settings all you want. It won't hurt anything - just don't switch it when the bike is on! Supposedly you can fry the CDI that way, so it's probably better to play it safe.

How to guide for the 1997 - 2002 LC4 Adventure:

I have a 2000 Adventure, so I'm more familiar with this. The CDI that came with it is the earlier Kokusan that wasn't switchable, KTM part # 584.39.031.200. Here there are two options: order the new 584.39.031.500 or order the Europe ONLY 584.39.031.300. The difference between the two is the wiring harness connecters. The 584.39.031.500 that we can order in the USA from any dealer should work on 1997 - 2002 models just fine, but you'll have a fun time installing the thing since you need to know which wires to splice into on the wiring harness as the connecters don't match. I'm not an electrician so I ordered the 584.39.031.300 from KTM Sommer in Germany. It looks EXACTLY like the 584.39.031.200, having the same wiring harness connectors, but has two additional wires coming out of it. One is RED/black and the other BLACK/red. This CDI comes with NO instructions whatsoever, so I had to talk to the guys at KTM Sommer to figure out that when these two wires are CONNECTED - 95 RON and DIS-connected - 80 RON. YES, you make a LOOP for the 95 RON. These wires will not be connected to the wiring harness!

In the pic you can see my CDI and a blue wire holder coming out of it, then a bunch of wires coming out of it. The red and red/black wires make a loop connection for 95 RON. Disconnect for 80. Ignore the mess of red/black wires in the top-left corner - those are for my alarm:

And now for the fun:

It works. When riding through Siberia last summer I had to use 80 ocatane a few times. No problem when switched to the low octane mode. I actually ran 92 octane most of the way through Russia and kept the CDI on the 95 octane mode. Doesn't ping if you don't push it hard. Pings like crazy on 80 RON though if you don't switch it.

Mongolia was a bigger test as outside of the bigger towns there is only 72 or 76 (claimed) octane. It looks very much like diesel - very oily. Once the pump attenant started pumping (human powered - no electricity) and I didn't notice it actually WAS diesel until a couple liters had gone down the tank! Mixed it with some nice 72 RON and all was well. The switched CDI handled it great.

And the not so fun:

CDI fried of its own accord in Vladivostok grounding me for 3 weeks while I waited replacement. I don't know if 584.39.031.300 is less reliable than the previous 584.39.031.200 or the later 584.39.031.500, but I think I must mention it. I replaced it with another 584.39.031.300 and it has been trouble free ever since (20,000 km).

Hope this helps someone. I sure had a lot of questions when I first went down this CDI path and I really had to struggle to find the answers.
"Improvement makes strait roads, but the crooked roads without Improvement, are roads of Genius"
- William Blake 1757-1827

spake Rad, "The KTM will reward you like a very expensive mistress where the BMW will reward you like a, like a... like a wife "

CountPacMan screwed with this post 04-06-2005 at 02:00 PM Reason: correction + addition of pictures
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