Ignition fault

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hphilbo
Posts: 24
Joined: 26 Oct 2020 17:21
Location: Lancashire

Ignition fault

Post by hphilbo »

Having my got my 1976 350 sport running well, the bike has now developed an ignition fault. The fault only shows itself once the engine is hot and results in loss of spark to the front cylinder. Let the bike cool down and I can start it and it will run on both cylinders, till it gets hot again. Having watched some excellent videos by Soren Hansen I believe the fault lies with the pick up module. It is a gen 2 red module and has seen better days, both coil blocks are cracked. I’m tempted to go for a black pick up module from Nuovary, which with diodes installed in the red wires should be compatible with the original transducer/coil modules. I suspect many members will have been here before and I’m interested to hear any recommendations on how to proceed and how best to obtain replacement parts.
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Ignition fault

Post by Steve Brown »

If the pick up is cracked then it may well be faulty internally too. I guess you have tried swapping the transducers to see if the fault stays with the same cylinder or not?
Assuming you have done that than I would go ahead and replace the pick up.
All donations to the rest home for old Camels, Leicestershire.
BumbleBee
Posts: 140
Joined: 13 Jun 2017 21:10
Location: Reading

Re: Ignition fault

Post by BumbleBee »

Don't throw it away though. In the extreme they can be de-potted and rebuilt. Possibly not economic for everyone, but if you throw away a broken one then nobody's ever going to repair it.
G&A
Al B
Posts: 47
Joined: 03 Feb 2017 20:34
Location: Luton, UK

Re: Ignition fault

Post by Al B »

I bought one from Nuovaray which was quick and easy, it was pre-brexit and import duties though
dunk 1
Posts: 208
Joined: 25 Oct 2007 18:16
Location: cumbria

Re: Ignition fault

Post by dunk 1 »

I had similar issues when I first got my bike - a 79 sport, I would repeatedly manage to get an almost uncannily accurate 7 miles before I lost the front cylinder, it would then start again when cool only for the issue to repeat.
The stator seemed to be the issue on mine and was resolved by getting it rewound.
Thanks - Duncan
dunk
norbert
Posts: 750
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: Ignition fault

Post by norbert »

To me this sounds very much like a pickup that is slowly saying good-bye. You should take a ride withot the cover of the pickup. Probably it will run better. Then you know for sure, that it´s high time to look for anoter one. Once in the early 80ies, on my only trip ever to England and Ireland it took me a week to figure out, that the bike ran quite normal without the cover. I could make my way back home even when raining. But a week later the pickup gave up definetly.
hphilbo
Posts: 24
Joined: 26 Oct 2020 17:21
Location: Lancashire

Re: Ignition fault

Post by hphilbo »

Further investigation has revealed the bike actually has a gen 1 red pick up with a gen 2 rotor so not sure if I can still go for a black pick up option ?
I know the coil arrangement is different but the rotor would be compatible.
On the alternator front I'm getting 210 ohms on the ignition winding which is acceptable but the output voltage seems odd. 60v at 2000rpm, 78v at 3000rpm falling to 47v at 4000rpm, same at 5000rpm. Is this normal or do I need a new coil or rewind. If so any info on spares / rewind specialist gratefully received.
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Ignition fault

Post by Steve Brown »

I should sort your pick up out before doing the flywheel coil. There was an article in either a recent ATG or possibly on the Netherlands club website explaining the different rotors and pick ups. That will probably tell you if the nuovaray pick up will suit the rotor you have.
All donations to the rest home for old Camels, Leicestershire.
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: Ignition fault

Post by 3potjohn »

Indeed the pickup and transducer combinations are clear on the NL website. If you could get to the rally I could bring a black pickup to try but I do not have a red.Depends on your transducers I think.
John
harrymuffin
Posts: 292
Joined: 07 Apr 2014 16:06
Location: west midlands

Re: Ignition fault

Post by harrymuffin »

The later transducers are made for either 350 or 500's, bt the only difference is a slight difference in advance curve by using a differnt resister. You can use either type as a pair on any size engine as long as you set the full advance for the particular machine. I ran 350 transducers on a 507 engine without any noticeable differance in performance, just made sure at 6000rpm the ignition was at maximum advance from there both types retard. You cold of course fit tranceducers from a Lambretta either Italian or Indian ones, I have a pair as back ups.
hphilbo
Posts: 24
Joined: 26 Oct 2020 17:21
Location: Lancashire

Re: Ignition fault

Post by hphilbo »

Thanks for all the tips. I’ve taken the plunge and bought a new black pick up from a well known uk source. I’ve made up some leads with diodes to connect in series with the red wires as per Soren Hansen video. Static timing is a bit imprecise as there are no marks on the new pick ups but she runs. Awaiting delivery of strobe for set-up. Fingers crossed!
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Ming
Posts: 798
Joined: 01 Aug 2014 16:32
Location: France
Location: Central France

Re: Ignition fault

Post by Ming »

I vaguely recall a method of balancing the advance on transducers using a small potentiometer to determine which transducer needed a small resistor added in series. I don't recall the chap's name - possibly Mario? Maybe someone on the forum remembers?
hphilbo
Posts: 24
Joined: 26 Oct 2020 17:21
Location: Lancashire

Re: Ignition fault

Post by hphilbo »

Final update. Bike now running really well with new black pick up from Mdina fitted and timing set with strobe. I made leads up to incorporate diodes in series with red wires on pick up. This per you - tube video by Soren Hansen. He has made a series of videos just on Morini electronic ignition which I whole heartedly recommend for any one with an issue with the original system.
Thanks again 👍.
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