North Leicester Motorcycles Ignition Module Diagnostics

[72degrees]

The 2C/375 was going well on the Isle of Man and I'm sure Corsaro Chris will give an account of the MRC activities at the Classic TT. Started pretty much first kick every time. Started first kick to ride off the Manannan at Liverpool on the way home, then expired with a pop and bang 200 metres from the pier head.

No sparks. I'd taken a spare 'known good' red pickup, but swapping that in didn't bring it back to life so I had to get on the phone to Footman James who arranged recovery.

On checking this morning, not in bright sunlight, there is a very feeble spark. Disconnected the ignition switch, and checked all connections/earths but no improvement. The stator was supplied by NLM four years ago (and the rotor re-magnetised) . Still 300 ohms resistance on the green wire and 80+ volts AC at kickstart speeds. In any case, in my experience the ignition winding usually dies slowly, leading to poor starting rather than fail suddenly.

The transducers were replaced with the NLM 'box' and conventional HT coil system at the same time as the rewind. I can't see how it can be anything other than something gone pop in that (unless by bad luck the 'known good' pickup has become bad).

I'll give NLM a ring, but apart from substitution, has anyone got any idea on diagnostics for this unit? I can't see two HT coils failing at the same instant, All the connections are sound and the earth is secure. I suspect resistances between connections or aren't going to tell me much, but I guess I should be getting a voltage spike, (12V), across each coil as it is kicked over?

[MickeyMoto]

Surprising what people will do to avoid paying for petrol...

I gather this is on both plugs? if so, I would trace back to common parts, on the premise that the cylinders fire individually, and the chances of a coincidence being remote (although not impossible)..

Yes, it does go very well, I think keeping the 250 badges is a brilliant way to burst a few bubbles!

Mike.

[72degrees]

Yes, both cylinders. More prodding around with the multimeter shows the two TEC coils which look very like the ones in this Rex's Speed Shop link
(http://www.rexs-speedshop.com/epages/es ... ducts/HTC4) have identical primary resistance (allowing for lead loss) of 0.3 ohms and secondary of 7.9 K ohms which seems about right. The output from the 'CDI'? unit to each coil is at peaking at 30v DC if not connected to a coil and virtually nothing if hooked up. The spark from both leads is feeble and will only jump a gap of 2mm or so (and may not be correctly timed). One quick test would be a known good OEM transducer. I've dug one out of a box in the shed but it can't be relied on as 'good'. I'll try hooking it up direct to the green stator wire and one pickup lead and see if that gives a decent spark tomorrow though.

I'll see what NLM say and if they are prepared to supply a module on a sale or return basis for a substitution test. Also contact Rex's Speed Shop and ask what the HTC4 resistances are and what voltage they need to fire, or if there is a TEC coil that looks the same but works on lower voltage.

No hurry, fortunately, and at least it didn't conk out whilst doing a demon overtake over The Mountain while creating myths about a works prototype Morini 250

[3potjohn]

Bad luck.I only time i've had similar was on a conventional ignition system with coils and battery,a wire had come off a coil.One backfire and then nothing. 2 hours to get the bike trailered back and 2 mins to fix it.Will be interested to know what you find.
John

[norbert]

I also was looking for sparks and becoming mad over it these days

If your pickup is a black one you can check the resistance between every red cable and the blach earth one: it should be about 54-56 Ohm.
This does not work with the red pickups because they have a diode inside!

A sudden death of the two tranducers at a time is ony posible (from my point of view) if any green cable has had contact to 12 V (red or brown cables). This can, if Murphy wants to fastidiate us, happen in the main switch (the thing where we turn the key). If you take of the green one from that main switch, it may work again. The Problem is that if the fault is there, your transducers are allready burned

Maybe i did not understand well. There are no sparks at all or they are only poor ones? In the last case first suspicion would be the coil on the generator. But 300 ohms are pure luxury Have you checked that the earth of the pickup is in good condicion?

good luck!

norbert

[EVguru]

My test for basic functionality will work with the NLM box, which is based on the original circuit.

[72degrees]

My test for basic functionality will work with the NLM box, which is based on the original circuit.

Which is?

[72degrees]

I also was looking for sparks and becoming mad over it these days

If your pickup is a black one you can check the resistance between every red cable and the blach earth one: it should be about 54-56 Ohm.
This does not work with the red pickups because they have a diode inside!

A sudden death of the two tranducers at a time is ony posible (from my point of view) if any green cable has had contact to 12 V (red or brown cables). This can, if Murphy wants to fastidiate us, happen in the main switch (the thing where we turn the key). If you take of the green one from that main switch, it may work again. The Problem is that if the fault is there, your transducers are allready burned

Maybe i did not understand well. There are no sparks at all or they are only poor ones? In the last case first suspicion would be the coil on the generator. But 300 ohms are pure luxury Have you checked that the earth of the pickup is in good condicion?

good luck!

norbert

In the bright sun at Liverpool what spark there was , was too weak to see. In the shade , inside my garage, I can see a feeble spark at the NGK BP7EVX plugs. Straight from the end of an HT lead (no cap) it will only jump a very small air gap. Not using OEM transducers. The NLM system I have fitted uses one CDI box and two separate small coils. Second generation red pickups (tried two). The earth is good. My money is still on a failed capacitor in the NLM module.
I really need to borrow at least one known good OEM transducer to prove it. Perhaps I can borrow one from the founder's Sport

[Ralph]

Could the flywheel have moved on the shaft?

[72degrees]

Could the flywheel have moved on the shaft?

I had a quick look with the side cover off in Liverpool to check for any damage to the stator wiring and all looked OK. Yesterday I had the front rocker cover off and checked that PMS1 still lined up where it should by feeling for TDC with a probe through the plug hole and it was spot on. So the flywheel hasn't moved.

It has to be said that the mounting of this new system on a 250 takes a bit of ingenuity as the OEM transducers live under the right hand side panel above the reg/rec - not under the tank. Finding somewhere to put the box and keep it securely mounted but isolated from vibration wasn't easy. In the end I ditched the tool box 'can' and used big zip ties and dense foam rubber sheet to fasten the CDI mounting to the frame. I made up an alloy plate to mount the two TEC coils on to the OEM transducer location points. It may be that the vibration of the tuned 375 (not helped by the 250 frame only having 3 point front engine plate) wasn't damped enough and has killed a component of the CDI circuit.

I'm tempted by the Sachse digital ignition but I fear it wouldn't stand up to the vibes either. I will go and talk to them on their stand at the Classic Mechanics show next month. I might just go back to standard transducers. Before this incident it has been starting and going very well, but that may have been more down to the tip-top ignition winding output (plus my favourite fancy plugs) than the NLM module.

[72degrees]

My test for basic functionality will work with the NLM box, which is based on the original circuit.

Which is?

Ah, I remember your demo at the AGM now!
https://www.youtube.com/watch?v=CWgLYidtHVw

[72degrees]

It lives!

I'm still slightly mystified as to what the problem was. NLM sent a new ignition module which when it arrived didn't want to give a spark at all even though the old one was feebly.

So I did what I should have in the first place and took the whole system (stator, rotor, pickup(s), module(s) coils and HT leads to NLM for Ollie to test.

A lot of swapping around proved my stator and rotor are tip top still. Both pickups seemed to work but the one on when it stopped did seem to drop out at high revs (though it seemed OK at low - so go figure why it wouldn't start). The replacement pickup did seem to be not brilliant with either of my OEM 2nd generation red pickups though fine with one of NLMs new magnet based ones. So I returned home with a another module (of the newer style with two groups of cables).

Rigged it up quickly with the spare pickup I'd tried in Liverpool and it started first kick!

I now think that the problem was failure of the slightly rough (the cables had been replaced and soldered on) pickup I'd been running Ok on all Manx week. Then I messed up putting on the spare that it is now working with. Put the whizzy round bit in 180 degrees out (though I made sure it matched the one taken off for position) or connected up the leads backwards or both. Should have spent more time trying other options.

Saves me lashing out on a Sachse system anyway. I'll need to source a spare good pickup though to take on other trips as it seems the most frequent failure. I found an early NLM one needed too fast a kick for me. Is any one selling suitable pattern 'red' ones?