350 ignition

[Gpz900r]

Having just obtained a early 350 sport that is difficult to start I have checked out the resistance of the generator and its definitely 297 ohms, strange as some owners are saying this figure is not correct, anyway its producing a poor spark when kicked over so can anyone recommend a alternative system

[Sicxtyone]

Hi gpz,
Having recently gone through this on my '76 Strada, there are some things worth checking first. Is what you have the standard set up? If so you don't mention if you have gone over what's there.
All earthing points need to be spot on especially transducers, as do basically all electrical connections inc feed to ignition switch. If there isn't an engine Earth on the lug behind the rear cylinder try fitting one, I ran mine to the earthing point on the plate that mounts the fuse board and the regulator.
Check the pick up and magnetic rotor (make a note of pick up position before removal) check for cracking in pick up. Mine was rusty on the four steel poles? On the inside. Also possible damage to the two red wires where they attach.
Check all terminals at the transducers for soundness especially the blue wires to earth either side of the headstock.
Change the HT leads/plug caps.
Is the spark weak on both cylinders?
If not already done so the morini ignition system is explained on "you tube Soren Hansen morini ignition part 1" should get you to it.
I replaced my transducers with the piaggio cdi boxes, get the right ones! and had the Tacho driver made up. Bike is now starting and running sweetly.
As you know there is loads of help on here and folks will be along I'm sure with advice. Also search topic can be helpful.
Where are you based?
I'm in West Sussex on the coast.
Graham.

[Ming]

Hello gpz. The coil resistance figure is only a rough indication of the state of the coil. A true indication would need an impedance meter and even then the windings could be breaking down with temperature (40 odd year old varnish and use). As Graham says, there are videos on Youtube (Soren and Paul Compton) which show how to test the components, all of which are replaceable. Many will argue that the original system is best suited to the bike, and probably cheaper to fix than a whole new one. What you have is:
Rotor - can be remagnetised.
Coil - can be rewound, either commercially or DIY.
Transducers - can be replaced or home made.
Pick up - possibly the difficult part, can be repotted, can be replaced.

[Gpz900r]

Thanks for your help, the spark is weak on both cylinders but it can be bump started and is prone to stalling until its warmed up when it runs great. Will check all the earths etc but I suspect it is the generator coil but in the long run a more modern system would benefit the bike ? And I'm a great believer in battery coil ignition it's so simple and extremely reliable, I was looking at a Horse Power system that seems good value.

[Sicxtyone]

Horse power system? Tell us more.

[Sicxtyone]

Hpi systems looks interesting, anyone used them on a morini?

[3potjohn]

Apart from the excellent videos already mentioned. This thread may be of use
http://motomoriniclub.nl/forum/viewtopi ... 579&p=4560
My experience over about nine years is my coil was around 175 ohms and the bike was difficult to start though ran well. I had the coil rewound and the problem went away. I also had a transducer fail about 3 years ago and instantly lost a cylinder, of course this happened at the bottom of a very steep hill. A spare unit fixed it.
I would say that the system is fit for purpose so don’t give up on it yet
John

[Gpz900r]

never heard of this company before but the website shows a system for the morini 350 which allows seperate timing for both cylinders by having adjustable pickups not sure if the electronic tachometer will need a new connection
.I will go over the entire system next week and see if a new ignition source coil will sort out the poor starting

[72degrees]

If the spark is definitely weak on both cylinders it might be worth checking the A/C output from the stator ignition winding first. If that is OK then it points to earths (main one from frame to crankcase present and correct?), both transducers or the pick up. It can be a bit of a mission homing in on the problem when substitution may be the only certain diagnostic. I know of at least one person who gave up and decided to just go straight for a Sachse system.

I'm hoping my currently good OEM type II red pickups keep working as I have opted for the NLM module and conventional coils solution, with a rewound stator and re-magnetised rotor. Not had much luck with an early NLM 'performance' pickup, but others have had good experiences so if one does fail I may try one again.

[EVguru]

There are definitely 300 ohm coils, there has to have been some reason for that value finding it's way into the factory handbook.
Most though started life at around 220 (the higher resistance coils may be more common on early bikes).

By far the simplest and cheapest thing to try is to remagnetise the rotor. Unless you plan on replacing the whole alternator, rotor and ignition, you still need a good charging system. I have the remagnetiser on the club stand at Stafford twice a year, or you can bring it to my workshop, or post it.

[Gpz900r]

Thanks Paul I may take up your offer I will be in touch
Steve

[Gpz900r]

Just an update on the 350 sport ignition ,so ive been through the system and checked everything I could think of and still have a poor spark so I placed the
bike on my mot rolling road with both plugs resting on the cylinders and switched the machine on (it rotates the back wheel at 3mph) put the morini in 1st gear watching both plugs I could see the spark was weak and intermittent
so I removed the plug caps and checked the bare ht lead it now sparks all the time but won't jump much more than 4mm,now I put some new plug caps on with no resisters and we have a spark at the plug.
after 3 or 4 kicks I can just about get it to fire but its not perfect,so is it the generator coil ?

[mbmm350s]

so is it the generator coil

perhaps, but also as Paul suggested weak magnetism of the rotor, especially if you have a flat sided rotor with no fins like below

series1rotor.png (47.35 KiB) Viewed 8204 times

With this coil resistance measurement is difficult to be definitive because one needs to know what the starting resistance when new was.

A 297 ohms measurement now of a 400 ohm scooter coil is bad. (vespa coils can be fitted, though I don't recommend it)
a 297 ohm measurement of a coil wound with too thin wire might be bad
a 297 ohm reading on a rewound coil or new coil with the correct wire is good, but doesn't eliminate possibility of breakdown in operation.

I concur with Paul's experience I have made many measurements of generator windings the majority of genuine ones on working machines are around 220 ohms +/- 10 ohms
If the measurement is below 200 ohms then I advise rewind.

With an oscilloscope the voltage can be measured, the peak should be 100V at tickover speed.

For me step one would be remagnetise the rotor. Then consider the generator winding. Component substitutions may be helpful.

All the best
Mark

[Gpz900r]

Ok so it's the ignition source coil does anyone know where I can get it rewound

[72degrees]

Ok so it's the ignition source coil does anyone know where I can get it rewound

That nice Evguru can I think. Or:
www.rexs-speedshop.com

Postal Address:
Unit 1, Russet Farm
Redlands Lane
Robertsbridge
East Sussex TN32 5NG

+44 (0) 1580 880 768

They did one for me fairly recently March 2019.