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Hello, I hope someone out there can help me. I have a recently imported 500, tuning unknown, which has a fault where whilst on the road and opening up the throttle, swiftly under load and up to normal running temperature, the engine will cut out and die. At first I suspected carbs as it was running rich, but I have since weakened it off and as it doesn't fluff and pull through I now think it is ignition based. (Windings breaking down within the ignition?) Your thoughts would be helpful, to help me make it to the track day. Thank you.

Hi,

fuel starvation? Bunged up taps?

Please can you let us know the ignition system fitted is it standard Ducati-Electrotechnicca with red pickup and black transducers with red dot.
or later black pickup with grey transducers or something else?
OBLIGATORY MORINI WARNING: do not allow 12V DC from battery to connect anywhere to the green wires to the transducers - these are AC CDI units and putting DC on them will kill them if you kick it over!


First to check are the obvious, and apologies if you have already done these basic checks
HT leads and connections. particularly look for HT lead corrosion
Security and connectivity of transducers earths (at frame) and engine earths
Condition of spark plugs and caps.

At about what rpm does the engine die, would you say it was like a rev limiter.
Do you think it is one cylinder or both ?
Does the bike start easily on the kickstarter.

If confirmed an ignition fault It could be transducer coil breakdown, generator winding breakdown, or weak rotor magnetism .
Sometimes there are faults in the ignition switch.

And In my experience its only by known good component substitution can it be quickly diagnosed and even then we need to return the original
component and if the fault comes back then it really was that and not some faulty connection fixed by the disturbance of parts.

Mark

Hello, thank you very much for your reply.The bike had been set up in Italy as a track day bike, so no kickstart or ignition switch.I start it on a starter roller,& I would say it is a reluctant starter. When it does cut out I think it is both cylinders as the cut out is total,not spluttering & it occurs around 5000 ,but I feel it is just as likely to do it if you grab a handful of throttle as apposed to it being just rev related. I will check the fuelling system again as you suggest,but do not really know how to start the electric side of things, anyone out there willing to do it as a job? as I need to get it sorted soon. Thanks.

Hi,

For track day use most would replace the electronic fuel tap (on the left side) with a manual tap. The electric ones often don't work properly.

Are the carbs clean?

If you have basic multi-meter then you can do some simple checks of the ignition system, but we need to know what is fitted.

Please can you let us know the ignition system fitted is it standard Ducati-Electrotechnicca with red pickup and black transducers with red dot.
or later black pickup with grey transducers or something else?.

You can search the forum there are many threads on how to check the ignition system

Mark

Hello ,yes the taps are manual already on a plastic tank , I will find out today what ignition system is fitted & i will do some more checking on fuel etc as you suggested. Thanks.

Just checked and it is grey transducers with black pick up,i will try and check connectors etc tomorrow. Just out of interest, does the kill switch need to be wired up in a different way to normal on a Morini? Thanks.

Treebod wrote:... Just out of interest, does the kill switch need to be wired up in a different way to normal on a Morini? Thanks.

Shorting the green lead from the stator (the source coil for the transducers) to earth cuts the ignition.

Hi
As ming says:

Shorting the green lead from the stator (the source coil for the transducers) to earth cuts the ignition.

So a faulty switch could cause the engine to cut out. If you can rig up an alternative then disconnect the original as a test
After an experience with a BSA with a jammed throttle i couldn't advise simply disconnecting it....

The black pickups/grey transducer combo is the later setup.
The final series of grey transducers with a bulge are the best with a stronger spark than the flat black ones

You can see some good information here from our friends in Holland.

http://www.motomoriniclub.nl/tech.html

Mark

Thanks for the ideas, after stumbling across an old post ,I am now suspecting stator ignition windings,as the symptoms he described were very similar.Any ideas where I can get it done quickly? Thanks again.

And I take it the stator on the 500 is different from the 350?

Hi,

And I take it the stator on the 500 is different from the 350?

The 500 stator (for the 500W roadbike model) is the one on the left, the early 350 (sport/strada) on the right.
The 500 stator has 4 wires, Yellow,yellow (which are the lighting circuit) green (for the CDI ) white (earth)
The original 350 stators as in picture have an additional red wire in the lighting circuit, and no white wire. 500 off road bikes stators are different again.
If you measure the resistance of the green winding to earth when it is disconnected and it measures under 220 ohms you should consider rewind, if under 180 ohms the rewind is a must. Initial specification is 300 ohms (but often the rewinds are a little under this at 270-280 ohms)
Rex's speedshop can re wind

I think you should confirm all the basic things before the rewind.

Mark

Hi,

The bike had been set up in Italy as a track day bike

If there is no need for lights etc then of course you can use a 350 stator.

You can also sacrifice the lighting coils and have two independent CDI generators (must not be connected together) one for each transducer,
if you are thinking of rewinding (higher cost though)
Mark

Does it run OK for a while when stone cold (you can coax it above 5000 rpm on a wide throttle)?

If it's refusing to start for a while after cutting out when hot it does suggest a possible heat related ignition issue (if fuel starvation has been ruled out). I'd add a potentially dodgy pickup to the list mbmm350s mentioned.

Presumably you have checked for a spark immediately after it dies and won't re-start?

Hello,thanks for your input,yes it does run ok for a while whilst cold,and yes I think you could rev it higher from cold,although I am cautious about reving frpm cold anyway,so I wouldn't swear on it.And yes it will not start straight away afterwards, you have to let it cool down,and the trouble has been that both times it has dumped me away from home on a test run,so have not been able to check for a spark, but will try to induce the problem now. Have checked stator (green wire to earth @ 100k on my old Avo meter,came up with 750ohms resistance? will bear in mind what you say about rewinding without lighting coils. Thanks again for your help, I am getting desperate now

Have checked stator (green wire to earth @ 100k on my old Avo meter,came up with 750ohms resistance?

may be your AVO needs a new battery! If its a MK8 or similar what did it read on the ohm setting?

Mark