Commander Ignition problem

[BANJOMAN]

I put this on as a new topic as i am looking for possible solutions etc. I have (I think) exhausted all avenues and Graham at Startright has suggested a lot of possible solutions none so far have worked! He is going to try and dig out a Boyer box to try.What happens is that the revs fluctuate for no apparant reason. I have filmed it and put it on YouTube http://www.youtube.com/watch?v=ImmIIqjBTO0I have a Digital box fitted. This is a replacement for the original one that did the same. What else have I done/tried:1. New ignition pickup fitted before engine rebuild - no difference2. New ballast resistor - no difference3. Ignition box hot wired from battery to remove possible faulty ignition switch - no difference4. Alternator disconnected and bike run - no difference5. Complete new wiring harness.6. Kill switch cleaned7. Temperature thermistor disconnected - no differenceI do not have the side stand switch fitted - this was removed at a few 1000 miles from new - bike now has 103000 miles on it.The voltage is fine and steady at around 14V and charges fine.Now! Grahams digiboxes run fine on other rotaries so why not mine.If anyone has any suggestions that I have not tried I would be most grateful as I (and Graham) are at a loss to find a solution to what is happening here.My last Boyer failed around 200 miles before I took the bike off the road for the engine rebuild. The problem with the new digiboxes is why I took the bike off the road for the rebuild. It is extremely frustrating that the same problem exists after spending a fortune on rebuild and I am at my wits end!!StuartCaithness

[Dell Boy]

Is it sucking in air somewhere in the inlet tract. You don`t describe how it fluctuates. Try spraying EASY START around the inlet tracts with the engine ticking over. If it speeds up you have an air leak & revs will fluctuate. Derek.

[BANJOMAN]

If you watch the video then you will see how it fluctuates. The video up to 2min 20sec is at tickover. After this point I increased the bikes revs to about 2500 rpm.I experienced the inlet tracts problem earlyin the bikes life and therefore at the rebuild I made sure all joints were smeared with Silicon following assembly. Thanks anyway for the suggestion but I am reasonably certain this is an electrical fault

[Dell Boy]

I couldn`t get the video to play. it froze every 2 or 3 seconds so I gave up on it. Derek.

[graham]

I've removed my own digital box from my Commander for you to try. It's run reliably since I fitted it about 15000 miles ago.I'll try to pick a working Boyer box for you to try as well.We'll get there, Keep up the good work!Graham

[BANJOMAN]

For Dell Boy If the video freezes it is just buffering and may take a time to download/view.I get this with YouTube sometimes!

[Rotor 1]

Banjo man,Did you try another rev counter? The contacts will possibly rusty? inside or outside?Rotor 1

[Richard Negus]

Very useful video !Ignition retard stays at full advance (at all engine speeds) when the temperature switch or thermister is open, telling the ignition that the engine is 'cold'.When the switch/thermister is closed, it says that the engine is 'hot' and the retard curve operates to give a steady idle around 600-800rpm.Boyer ignitions can revert to full advance if the engine becomes 'cold' again - but the digital system is latched in retard until the ignition is switched off. Even though the engine is hot, it starts again at full advance to give a starting boost for the first 25 revolutions and then returns to retard.The video seems to show that the ignition is randomly jumping in and out of retard.That can happen on a Boyer system if the switch, thermister, or blue wires have an intermittent fault - but not with a digital system.For a digital system to jump like that suggests that the ignition power is being switched on and off, either in the bike wiring or inside the box. It might be in the white/yellow wire (which you have by-passed) or in the black earth wire. Try connecting both directly to battery + and -.Have you tried disconnecting the yellow tacho signal wire, on the off chance it may be a tacho/tacho wiring fault ? However, I can't see that sort of fault causing the box to latch and unlatch.If I play the video again, I think I lose this draft - but does your engine idle steadily at 600-800rpm, which is with the needle virtually on the stop ? If not, you may have a mechanical problem - but I don't think that might cause such sudden changes in engine speed.R.

[Richard Negus]

Banjoman,I viewed the video again and see that immediately after start-up it is briefly idling at the correct speed (a little roughly perhaps) but then the fault starts and it sounds like intermittent full advance. Not a mechanical problem then.R.

[BANJOMAN]

Thanks to Richard, Graham and all others for replies.This evening I ran a neutral direct from the ignition box to the battery - No joy!I also tried the tacho (disconnected yellow wire from coil - again no joy.Realistically I think I have tried everything electrical! Will try the Graham's box when it arrives and hopefully this will not misbehave - watch this space.................................

[MrB]

I've run one of Grahams' ignition units fitted to my Commander engined IP2 for three years without any problems at all. Your video clearly shows engine fluctuation coincident with the red LED illumination. Strongly suggests it’s an electrical problem.Do you still have the paperwork that came with the unit? That states:Red and green = engine warm up (and then after warm up) Green only = engine speed 1,000 to 2,000 rpm. Your video could be showing the unit flicking between the two states, the effect being that the unit will switch retard on and off.You could try disconnecting the blue/black wires from the ignition unit to the thermistor and short the connections at the unit to force the unit to hot running. If that sorts it look for an intermittent fault on the (blue?) wires from the engine temperature switch / thermistor to the ignition unit. Could even be corrosion at the lug/copper cable joints if crimped cable connections are used.Johnny

[BANJOMAN]

Well!!! The helpful Mr Wilshaw sent me his commander digital box and tow old Boyer units. Tried his digibox, which runs fine on his commander, and the problem was still there - in fact I would say it was worse. Tried one of the boyer boxes and the bike ran lovely, no twitches on tacho etc etc.I also tried new wires from the temp sender but no difference to the digital units.If possible I will keep the Boyer unit once a price is agreed with Startright.Why wont the digital boxes run on my bike ??????????Why is it just my bike and why should the boyer work fineI am extremely puzzled and pi**ed off as I would like to run one of Digital boxes. I suppose I still have mine and can experiment.

[Dell Boy]

This saga has jogged the memory cells. I had this situation about 15 years ago on my Boyer fired Commander & the problem either lay with a failing voltage regulator or the thermistor/blue wires. I can`t recollect which & I gave the vehicle log to the new owner so can`t look it up. Derek.

[graham]

Don't you just love Norton Rotarys!In my 23 years of daily exposure to 'rotary radiation' I've often had to accept that nothing works quite the way I expect.The only thing I can suggest now is to change round the input from the trigger and swop over the plug leads. Can't see it making a difference though :-).I'm sure Mr T you will post the solution once you find it. I'm glad I could help and sorry you've had to work so hard.I take my hat off to you and will buy you a pint next time we meet.Graham.

[BANJOMAN]

Right everyone I need some joined up thinking here as to what the problem could be! I just got a new voltage regulator and fitted today.Boyer box runs fine but the Digital box is still 'All over the place' to use a technical term.The problem with the Digi box is obviously not a voltage related one!What the hell is happening with my bike???????

[rustynuts]

My suggestion is that it may be some kind of electrical disturbance that the digital box is susceptible to but not the Boyer. (I presume the Boyer is an analogue system, and if so would likely be less susceptible to electrical noise.)Is there any potentially electrically noisy equipment attached to your bike: e.g. an inverter for an HID light or anything microprocessor controlled such as a sat nav, which if either poorly designed or malfunctioning could be producing high frequency voltage spikes which are interfering with your digital box. You will not be able to see these spikes with a multimeter, but if you could lay your hands on an oscilloscope, you would be able to see if this is your problem. You could try connecting a capacitor directly across the power and earth connections of the digital box to try to shunt any high frequency noise to earth.Ignition systems can be as elecrrically noisy as they come, so it could be a case of your ignition system interfering with itself if there is something wrong with the installation. Sounds like you have eliminated the possibility of a poor power connection. Do you have either suppressed HT leads or plug caps fitted? These act to dampen the higher frequency components of the ignition pulses. Lastly, there have been many reported cases of automotive systems malfunctoining due to emissionns from radio transmitters, radar and even coils in domestic power meters. Do you still get the symptoms away from home?

[BANJOMAN]

To Mr R Nuts!No there is nothing non standard fitted to bike and the problem happans away from the house area.I have not looked at the plug leads or caps so may have a try with them after Easter - its one of the few options left. Do I need supressed or non supressed caps fitted?ThanksStuart

[Wayne]

HiI may be miising a point somewhere, however grahams boxes don’t retard as much as a boyer , you have to adjust the tick over, from 600rpm hot on my f1 with boyer with direct swap grahams box its around 2000rpm hot so on full advance regardless of temp, graham can explain this better than me, just lower the tick over to 1000 then fine tune once warm me when I bought my sport the owner had put grahams box on same thing 2000 rpm called in so graham could show me which hole in the frame was what for tick over now ticks over at 600 rpm lovly Motto you cant swap boyer boxes with grahams without adjusting tick over on f1s or sportsRegards Wayne

[BANJOMAN]

Thanks WayneI think I get your drift (ish). I'll see what GW thinks. Bike ticks over on both boxes at around 600 but doesn't rev as freely with the boyer box until over about 1500.ST

[rustynuts]

Do I need supressed or non supressed caps fitted?

I'm not sure what the original suppression arrangements were, if any at all; with an old analogue ignition system it probaly wouldn't have been necessary except to stop it interfering with all the TVs you ride past. Suppression can either be provided in the leads, caps or in the spark plug. Theoretically, the closer the suppression is to the source of niose (the spark) the more effective it is, so a suppressed plug is more effective than a suppressed cap. I see NGK do a CR8E, a resistor version of the C8E. It may be beneficial to use suppressed leads along with a suppressed plug or cap, or on the other hand it may be detrimental to performance to use both if you don't have enough spark energy; its a case of trial end error.

[Richard Negus]

The trigger unit produces a low voltage pulse as a signal to the ignition unit to switch the coils on and off, creating a spark at the plug. It is possible to induce a voltage in a wire if it is placed alongside and in close contact with another wire which has a pulsing voltage.Are the wires from trigger to ignition unit alongside, for example, the generator a/c wires anywhere?Are any ignition unit wires anywhere near the plug leads ?To answer another post, Norton used suppressed leads right back to IP2 prototypes.; un-suppressed caps and normal plugs.R.

[johnbirchjar]

I seem to remember some years back buying a couple of NGKCR8E'S from the "spark plug man" at Cadwell, and the Classic did'nt like them at all! the old girl would'nt rev and the tickover was all over the place, had to stop on the road side soon after leaving C.P. and put the old C8E's back in,I do'nt suppose this is your problem but I suspect that supressed plugs AND suppressor caps caused the spark to break down,but I thought it worth a mention, (seeing as you are now clutching at straws) regards J.B.

[BANJOMAN]

IT'S CURED!!!! It was the bl**dy plug leads and/or caps. Fitted new silicon leads and resistor caps and bouncy tacho has gone with the digi box!! Started initially with Boyer box and you could hear the difference in the engine noise. Swapped over to digibox and runs lovely with slight downward adjustment of the tickover.Boy am I happy!

[Dell Boy]

Well done, got there at last. It must of cost a fortune to get there though!!! Derek.

[johnbirchjar]

Good for you,you did'nt just give up and just sell the bike!!and we all proffit from your(expensive?) experiance,and how long did this diagnosis take? never mind,you are now one happy biker,take care and ride safely,J.B.