Can anyone please tell me if the Ignition Control Unit can be checked and is it a serviceable item.
I suspect it may be faulty as I have no spark from cylinders 2&3 despite having replaced the ignition coil. I have tried three coils in total so am happy that the problem lies elsewhere.
Any info gratefully received.

Hi Brind, ICU I purchased a s/h unit from Motorworks for £25 some time back .Just in case you need one

Brind wrote:Can anyone please tell me if the Ignition Control Unit can be checked and is it a serviceable item.
I suspect it may be faulty as I have no spark from cylinders 2&3 despite having replaced the ignition coil. I have tried three coils in total so am happy that the problem lies elsewhere.
Any info gratefully received.

Can you confirm if its K75 or K100?

If K100 2 and 3 are on the same coil so you may have failed coil, quite likely.

Change coils around and if it follows the coils then its a coil issue. If it stays then likely a Hall Sensor issue.

have you tested - cleaned the hall effects sensor connector under the tank , could be corroded and missing pulses from the sender ?

Thanks guys.
The original coil was burnt at the bottom so I assumed that was the problem. Changed the coil but still no spark. Have tried two other coils and still no spark. There is power to both coils. Trigger unit (HES) visually appears ok. I’ll check the connector under the tank.
Reluctant to change either the trigger unit or the ignition control unit until I can identify the cause of the fault.

Have you checked the #2 and #3 plug wires for continuity and shorts to the metal cap that goes over the spark plug?

Thanks.
I’m pretty sure they are ok but will double check. Anything I can eliminate should get me nearer to the cause.

Brind wrote:Trigger unit (HES) visually appears ok. I’ll check the connector under the tank.
Reluctant to change either the trigger unit or the ignition control unit until I can identify the cause of the fault.

Did you test them, or just look them? They're nice looking in their natural states whether they're sick or well. 

Click on the Portal tab at the top of this page then click on the link for the Tech Page. On that page, look for the Troubleshooting the EFI document. Tests for many engine management components—including the Hall Sensor, the ignition control unit and the coils—are illustrated and described within it.

Found it, many thanks.
I’ll work my way through it.

articles. That was exactly what I was looking for.
I checked the Hall sensors, including the hair dryer treatmeant and all was ok. Then checked the ignition coils. I had bought a pair of secondhand coils and fitted them both. One coil tested ok for resistance and the second gave no reading so I have replaced it with the original and now need to refit the tank and try.
Interestingly I checked the coil that was burnt at the bottom and the readings were OK. I can only assume that it was breaking down when it got warmed up.
I'll let you know how it goes.

Brind wrote:Thanks guys.
The original coil was burnt at the bottom so I assumed that was the problem. Changed the coil but still no spark. Have tried two other coils and still no spark. There is power to both coils. Trigger unit (HES) visually appears ok. I’ll check the connector under the tank.
Reluctant to change either the trigger unit or the ignition control unit until I can identify the cause of the fault.

That may have been caused by bad plug leads. Plug leads are high on the potential list. If you have original plug leads have your spark plugs got their bobbins on if you have NGK plugs?

The plugs are new NGK. Plug leads look to be original, numbered and with 5k Ohm end caps. Readings are 4.73- 5.26k Ohm.
The mystery now deepens. Yesterday I inadvertently left the ignition on while I went to get fuel, 20 mins. max. On return I filled the tank and tried to start the bike. The starter motor wouldn't run and I then noticed that coil (2&3) was very hot. ( it was the original coil(2&3) that was burnt at the bottom of the casing). The other coil was cold.
I tested the hot coil and could get no reading from the HT side, so appears to have burnt out. Primary side read 2.0 Ohms.
Although I am getting no reading from the coil, if I turn the ignition on the coil starts getting hot again.
Regarding the starter problem. When I turn the ignition on the load shed relay clicks in and when I press the starter the FI relay clicks in but not the starter relay.
Sorry to be a pain but I am a retired mechanical engineer and the electronics side leaves me lost. Even more frustrating is that the bike is
Immaculate and has only covered 10k miles from new.

Brind wrote:
I had bought a pair of secondhand coils and fitted them both. One coil tested ok for resistance and the second gave no reading so I have replaced it with the original

I apologize, but I am easily confused and my reading skills are declining.  Are you saying that one of the replacement coils was bad?  Was this before or after you put it on the bike?  Does "no reading" mean infinite resistance AKA open circuit?

Also, what is the status of your plug wires?  And do your NGK spark plugs have terminal nuts/bobbins?

Brind wrote:... I tested the hot coil and could get no reading from the HT side, so appears to have burnt out. Primary side read 2.0 Ohms.
....

 You have to get a reading. You either get open circuit, short circuit or some resistance in-between.  What do you get?

P,S. If your meter shows "OL" on the display when you attempt to read the resistance of the HT secondary, that means "Over Limit" or effectively open circuit because the coil's secondary winding is broken inside.

Apologies for any confusion.
Plug leads have the o.e.m. plug caps stamped 5k ohms. I obtained readings of 4.76 on three leads and 5.26 on one.
The first time the bike went onto two cylinders I had ridden about 5 miles and I limped home. Second time rode 6 miles for an mot and rode back an hour later with no problems. Third time rode 10 miles and went on two cylinders. That was when I found that 2&3 plugs were wet and the ignition coil casing was burnt at the bottom.
I replaced the coil with a second hand unit (untested) and when I started the bike it was still running on two cylinders.
That was when I was directed to the testing information on the forum so I removed the tank and went through the test procedure for the Hall sensors. All ok.
I replaced the fuel tank and that was when I went for fuel and left the ignition on. I put fuel in the tank but the starter would not operate. That was when I noticed that the replacement coil was very hot. I tested the coil and could get no reading (blank screen) between the HT terminals with the meter set at 200k ohms. I got a reading of 2.3 ohms between the spade terminals.
If I turn the ignition on the replacement coil starts to get warm, the other (original) coil remains cold. This I can’t understand as the 12 volt feed to the coils is common.
In summary,. The original coil was obviously getting hot, then breaking down, although it had never been left with the ignition on before riding. The replacement coil is also getting hot when the ignition is switched on.
The original coil, although the casing is burnt, still gives readings of 2.3 ohms and 2.3k ohms.
I also need to determine why the starter motor will not operate. When the starter button is pressed the fuel injection relay is activated but not the load shed relay or the starter relay.

I hope this may make sense to you, as I am becoming thoroughly confused!

How were you testing the HT leads?  Was it one test lead on one of the HT terminals and the other test lead on ground?  Or was it HT terminal to HT terminal?

A hot coil might mean that the ICU has a blown driver section.  If you swap primary connections from the hot coil over to the normal cool coil, does that formerly cool coil also start to heat up?

Hi Robmack. Thanks for your input.
Just tried swapping the primaries and yes the other coil started to heat up.
Re the plug leads I put one probe into the plug cap and the other to the opposite end of the HT lead. I don’t know if that was the right method.

Hi Brind, If it is the ICU Motorworks  have S/H units for about £30. S0 a cheap fix really

That sounds reasonable. I spoke to Yvonne at Motorworks a couple of weeks ago and she quoted me £90 but perhaps she meant for an injection control unit.
The fact that the ignition coil is getting hot without the engine running and that this problem has been occurring for some time does point to the cause being further back up the line.
I’ll try Motorworks and see if they have one. They offer them on a sale or return basis so I’ve nothing to lose.

Brind wrote:That sounds reasonable. I spoke to Yvonne at Motorworks a couple of weeks ago and she quoted me £90 but perhaps she meant for an injection control unit.
The fact that the ignition coil is getting hot without the engine running and that this problem has been occurring for some time does point to the cause being further back up the line.
I’ll try Motorworks and see if they have one. They offer them on a sale or return basis so I’ve nothing to lose.

Its about 2yrs ago when i purchased one .Dont think inflation is that bad

Looked on their website tonight £90 for a secondhand ICU and
£60 for an ignition coil. At least, thanks to forum , I now know how to test the coil on receipt.

Brind wrote:Hi Robmack. Thanks for your input.
Just tried swapping the primaries and yes the other coil started to heat up.
Re the plug leads I put one probe into the plug cap and the other to the opposite end of the HT lead. I don’t know if that was the right method.

To fully test the coil and HT leads, do the following three tests:

One more test to do on the coils.  You need to test between the primary tags to earth,  there should be no reading. even on the high resistance scale.

Many thanks for the inputs.
I’ll do the tests this morning before sourcing any parts

Allow me little time to have a look. I may have a used ignition unit you can have. Will message you but am out at the moment so wont be able to look until this afternoon.

Thanks

Problem all sorted!
Replaced the ICU and the (second) burnt out coil and all back to normal.
Very fortunate in that had I not accidentally left the ignition on I would never have found that the fault was in the ICU and not the ignition coil.
Although it cost me an extra coil, it would only have been a matter of time before the first replacement coil would have gone the same way as the original.
Thanks again for all the help. Fantastic forum.