Tale of woe...

[mick695]

Here is my story...

Went out for a run on the old rotary, about 80 miles, everything running perfect. About a mile from home the engine died at the traffic lights (water cooled Norton). It fired up again, but a bit sluggish. I looked at the trip meter which was showing 125 miles so I thought better turn on to reserve and go fill up. At the petrol station she fired up again, but with a bit more effort required this time. Got home and the engine died and would not restart.

Next morning with a cold engine she fired up, but only on the right rotor. If I tried to rev the engine it just died. It ticked over a bit rough, but the left rotor would not come in even when the engine was up to temperature.

Pushed the bike into the shed and did all of the usual checks, swapping coils, plugs, HT leads etc, still only running on the right rotor. Put it all back together and now there are no sparks on either rotor

Beginning to think that the electronic ignition (Norton Digibox) may have failed.

Questions.... Can these units be tested? repaired? swapped for a Minimag unit? Anyone got a tested and working unit for sale?

Any suggestions welcome.

Cheers

Mick

[johnbirchjar]

I expect someone out in Rotory land will have a spare that you can borrow,failing that, Minimag is usually very accomodating (he even tested & repaired the 'leclic regulator on my golf trolly some years back)worth a phone call?good luck,J.B.

[Ian Mc]

Make sure that the plug caps are 5000 Ohm suppressed, 10,000 at the most.Remove the plugs and earth them to the fram so you can see the spark. On the three pin plug with brown,yellow and white wires, connect a 12 volt 5 watt test lamp between negative and the yellow wire, the lamp should glow. Spin the engine and the light will go off then back on as the flywheel passes the pick up. Same on the white wire. This will test the sensor. I had to set my sensor at 20 thou gap to register. You can test the plugs, leads and coils by dabbing a wire from the frame to the yellow wire, it should produce a spark, same with the white, as though adding a contact breaker. I have to fit new plugs every 2000 miles.

[mickm]

Sounds familiar to me. Try checking the connection that’s hidden behind the left foot rest plate. Mine came adrift and I lost all sparks.just a thought.

[mick695]

Well I'm back from holiday and back to the same problem of no sparks....

Thanks for the replies so far which have helped with some of the testing.

So far I have .....

Sent the ignition box and pick off to Julian at Minimag who tested both and returned then with a clean bill of health.

Replaced the battery, coils, spark plugs, plug caps, thermal switch and all of the fuses.

Tested all of the wiring in the ignition circuit and its all OK and I can get a spark by earthing each coil as suggested by Ian Mc.

Tested the ignition switch, kill switch and all connections in between, plenty of power getting to the coils and ignition box.

I can't get a result from the pickup test as suggested by Ian Mc and there is no means of adjusting the air gap which at present is approx 1.5mm but as far as I know has always been like this and I've never had ignition problems before. See attached picture. So perhaps the problem does lie here...

I'm running out of ideas now.... except for putting the thing on Ebay as a non-runner and passing the problem onto someone else

[johnbirchjar]

Daft question,but I suppose you have tried by-passing the side stand cut out switch,(I had a similar prob: many years ago with my Classic,and the side stand switch was the culprit,)J.B.

[mick695]

Hi John

Thanks for the reply... no side stand switch on the bike since I've owned it..

I'm going to spend the weekend taking out all of the wiring for the ignition circuit and make up a sub-harness to remove all of the old wiring and connectors. Fingers crossed

Cheers

Mick

[Ian Mc]

I had to file the holes to get mine close enough to pick up a signal. When you get the ignition sorted you can look forward to hours of fun setting up the carbs. I've had my Commander for 28 years, sometimes it just sulks for no obvious reason and decides to cut out at traffic lights after running perfectly for weeks. change the plugs and away it goes. Does anyone know of a better spark plug than C8E ?

[mick695]

Some progress today. I completely rewired the Low Tension side of the ignition circuit with new wires and connectors.

This has allowed me to check each individual connection and wire for continuity.

To cut a long story short.... I've tracked a problem down to the 6 pin connector from the original wiring which plugs into the black ignition box. By opening up the box and using a meter, it turns out that the centre connection (-ve Gnd) has broken down in the plug, so the box was not powering up...

I managed a work round, got 2 LEDs lighting up in the box (which I never knew were there), and a spark on the Left Hand spark plug. Now just need to play around to get the Right Hand side to spark... a job for tomorrow

Does anyone know what type of connectors were used on these boxes?

Now I've got another question... The 2 LEDs, the left hand is a steady RED and the right side a FLASHING GREEN... does anyone know what these LEDs are trying to tell me?

Anyway, amazing what you can get done on a wet July afternoon.

Cheers Mick

[johnbirchjar]

If memory serves(and you have a Minimag Box)the Green light means the ignition is working and the Red light will go out when the bike fires up,but the Green light stays on(I think)sorry I can't be more positive,It's been quite a few years since I worked on the 'leclics of a Rotory,J.B.

[Ian Mc]

Minimag light sequence, engine stationary
Red light on - side stand down.
Red flashing - ignition on, engine stationary
Red and Green on - engine warming up.

Engine warm and running
No lights on -engine running
Green -engine speed 1000 to 2000 rpm
Red on - rev limiter 9500 rpm.
If you have faulty HT leads you may get a rapid flashing red. Plug caps should be 5000 ohm resistance, do not use resistor spark plugs.

[johnbirchjar]

Ooops,seems like I got that well wrong,(it has all come back to me after reading MC's comments)sorry,J.B.

[PDC Racing]

"If you have faulty HT leads you may get a rapid flashing red. Plug caps should be 5000 ohm resistance, do not use resistor spark plugs."

Standard recommended spark plug is an NGK C8E which is a non-resistor plug. Also recommended is a CR8EIX Iridium plug which is a resistor plug but has a fine wire electrode and creates a stronger spark at a lower voltage which more than compensates for the resistor. They also have superior anti-fouling characteristics and up to ten times the life expectancy of standard copper cored plugs. Well worth investing in when only about twice the price of the standard C8E plugs.

[Ian Mc]

If the engine ticks over on both sides but cuts out on left side at small throttle openings, try removing the plastic pipe that drains the frame into the left inlet tube. Blow down it and listen for bubbles in the frame, the bottom of the tube should be in oil. That could be where the air is getting in. Or try clamping the pipe to see if it makes a difference. I had the problem on the Isle of Man after alot of heavy braking emptied the pipe, causing air to enter the left side.

[mick695]

Right now.... we have a result

Having had the Ignition box and pick up tested by Julian at Minimag.

Tested the coils, HT Leads and spark plugs.

Rewired the LT circuit with new wiring and connectors.

I traced the problem down to the original 6 pin socket and lead from the main harness to the ignition box.

The bike running one one rotor was caused by the little socket on the Yellow wire breaking down inside the plastic block. Power to the ignition box finally gave up when the black earth lead little socket failed too (see attached picture).

Seems obvious now, but when these connections were one minute OK and then fail the next time you check them

I took the lead and box to several electronic shops to be told that the plugs and sockets were not available. Finally a local electronic/amplifier repair shop hard wired a 6 core lead directly to the PCB inside the ignition box and fitted a waterproof gland to the hole in the box.

Wired the whole thing back to the bike, put everything back together, tested and got 2 good blue sparks, pressed the button and experienced a massive smokey start up

So the old bike is back to starting up on the button, tick over is good and the engine runs up to temperature, so just need a dry day to do some road testing.

If you've got one of the leads still on your bike and you get a problem with lack of sparks.... these connections are where I would start looking.

Thanks for all your help.

Cheers Mick

[johnbirchjar]

Pleased you got the old girl sorted at last,ride safe,J.B.