2KR CDI Unit

Hi Guys,
I have a 2KR model which is having some serious ignition issues.

I pulled up somewhere, waited 10 minutes for someone to arrive and then just couldn't restart the bike ?

I ended up looking into it and discovering that I have no spark.

I measured the primary and secondary side of my coils and my pickup coil and all was fine.
I don't imagine that both coils would die together anyway.

Either way, I thought it might be the CDI unit so I purchased another one off ebay.

I had a 1HX unit in there and bought a 2KR to replace it. They have the same plugs but one has a cable coming out and the other just has plugs on it.

They are the same type of plug and I was able to plug the 2kr unit straight in but the 6 pin connector has one more terminal in it than the 1HX ( which has only 5 filled ) and I starting to think that the pin outs might be different.

What I REALLY REALLY REALLY need is for anyone that is willing to take a photo of the connector going into their 2KR unit so I can compare the wire colours and try to work out what the hell is going on.

I'm otherwise completely stumped, my 2KR has no side stand switch and hence no cutout relay and the wire that goes into the 1HX module was always just unconnected and everything worked fine. So I really can't anything else that I check ?

Would appreciate anyones help and photo if they can take for me !

Thanks Alot !

 

Hi guys, there isn't a cut out relay at all so the clutch switch and neutral switch don't affect it. They only impact on the starter motor relay and the bike is cranking, just not firing.

Battery is getting a bit tired but i've hooked up a 12v charger that when I crank the bike delivers an extra 8 amps to supplement the battery and keeps the voltage up.

I've seen the controller is actually working and is fluctuating some voltage on the two wires that connect to the primary side of the coil but its hard to measure since ignition units usually open circuit the primary to cause the spark.

I'm going to pinch a scope meter tomorrow and investigate a little more into the output.

I might temporarily hook up a larger capacity battery to rule that out and investigate a little more into why the output of the controller doesn't seem to be making it through the coils.

I will post my findings.

 

Problem fixed - i took the long way to do it.

For anyone else though wishing to know, i confirmed my coils still worked by hooking them up to my sound card on my computer through the head phone jack and used a small freeware program to generate a 1.5V rms sine wave which i fed into the coils at 8kHz and managed to produce 114V rms. That proved they were working.

Next I used a scope meter on the pickup coil while it was unplugged and cranked the engine and saw that I had a nice clean pulse coming out of it. So that was working.

I tried the scope meter on the output of the CDI unit but it was too slow to observe so I ended up pinching a oscilloscope from work to watch it more closely and observed that the controllers output was a flat 12V that dropped with load when cranking.

I knew the CDI unit i purchased was from a working bike and it seemed odd that I had two dud CDI's so i knew there was something sneaky going on.

I ended up using the scope meter to observe the pickup coil output when it was plugged into the CDI unit and noticed that the waveform disappeared. I found this pretty odd so I investigated a little further. The resistance between the two wires was around 200 Ohm which wasn't too far off what the book said but when I measured the resistance from each individual wire to ground, one of them was only 0.4 Ohms, which was obviously wrong as i had the pickup coil unplugged and there shouldn't be a closed circuit if only the cable was unplugged.

So i found that the red white wire has a short to earth that didn't affect the resistance check across the pickup coil or the output waveform when unplugged ( as you would expect ) and it dawned on me that the controller itself was likely to earth one of the pickup wires as a reference and low and behold - it earths the green/white. Hence when I plugged the pickup coil into the CDI unit it was shorted to earth across both sides of the coil - hence no pulse.

Fixed it with two cents of electrical tape and wallah, bike now fires.

 

I wouldn't think so.

I had only recently put the engine back in after I replaced the crank because I shattered the number 4 piston big end bearing. Which is frustrating because its the second time I've rebuilt the engine, the last shattered the number one piston big end. What they say about them getting a lack of oil flow at high RPM is definitely right. What's even more frustrating is that I bought the second engine to replace the first - but the second had the same problem developing ! I ended up fixing this one. There is literally nothing in this engine i haven't pulled out and put back in. I even tried swapping the gearbox when the noise was in its subtle stage.

The crank I put in was a 2Kr crank, the engine is a 3LN1 and hence the tapered shaft is a different size that holds the magneto on. Hence the magneto is different and hence the stator is different. So I had to change the stator in the cover and the pickup is part of the same assembly.

The wires in the pickup shifted a little under their clips when I did this, only marginally, but towards some tiny holes.

When the bike was running my friend (who I was getting it working for and is a learner) took it for a test around the block. He was doing a U-turn and he dropped the bike underneath his feet. Most of the impact was on that stator cover. Believe it not, that didn't do it ! When I took him for a short ride to get my VTR, we went up a gutter onto a drive way. That did it, the bump the bike got when it bottomed out under our weight was the final straw and it broke through the insulation.

So the moral of the story is that this probably wont affect anyone else unless you do any work to the bike, move any wires into snug positions and then give it sharp shocks - otherwise you should be right.

 

You didn't say anything about replacing the pickup unit in that list.

Stick a multimeter in the back of the two pin plug acorss the two terminals that goes into the CDI.

Stick the meter on AC and crank it, you should see close to 1 V ac and if you stick it on Hertz you should see numbers bouncing around the 10 mark.

If you unplug it and measure resistance across the two leads you should get anwhere between 100 and 250 ohms depending on age. Measure the resistance from each of the leads ( from the plug ) to the metalwork of the bike as well - you should get an open circuit.

 

Definately grab another one- can't really diagnose anything without one, even one less then 10 bucks will do the trick.

Pickup coil is located in the Magneto Cover just above the stator. Picks up off the outside of the magneto.
Its the thing at the top when you pop the over off. If you follow the cable coming from the magneto it will have two connectors coming out, one for the stator current and one for the pickup - the pickup is the one with only two wires.

What model bike do you have, does your side stand has a micro switch that open and closes with the stand ? If the black wire with the white stripe coming from the CDI ( If you have one) is connected to something then thats another area to search, that wire is the cut out cire, a relay earths that wire if the side stand is down and your in gear and you let the clutch out, which is another way to tell if you have one, has your bike ever automatically killed the engine if you've gone to take off with the side stand down ?