1974 Mk111 450

[weggy96]

Hi Guys
I am having problems starting my 450 it will fire but not run I have a spark and fuel is getting through. I have tried every thing I can think of but no go. Up till recently it has run perfectly although a bit difficult to start from cold.The timing seems ok and the Amal concentric settings all check out.
Can anyone suggest anything ??
Weggy96

[blethermaskite]

Hi,
What type of ignition system have you on it?
Cheers,
George

[graeme]

Spark plug ?

[weggy96]

Hi George
The ignition is electronic as fitted by Ducati and I have a spark so I assume the plug is Ok
Weggy

[blethermaskite]

Is it motoplat or ducati electonica? if its motoplat the symptoms you are describing would suggest to me that it is failing, the motoplat system does this when it gets old.....hard to start ....and then ultimately just won't start at all, even when new the motoplat system had a weak spark at kicking speeds bit it still worked ok, mine lasted for about 30 years before it failed exactly like yours, ( I know its sparking but its not sparking under compression in the cylinder). If its the ducati electronica system it usually lasts longer but it fails in old age too, others have posted quite a lot of testing and repair data for these on here recently. These original ignition systems are all 45 years old now so I recon we have not done to bad with them
Cheers,
George

[weggy96]

Hi George
It has the Electronica ignition fitted and I have checked around and am unable to find replacement parts so if my system is faulty what is the fix??
David

[DucRedux]

One source for replacement is this dealer from the republic of San Marino, Italy. I have dealt with them on several occasions and have purchased components in person and through the internet with delivery though international mail. Other dealers in the UK may also have components.
Good luck.

http://www.ducativintagestore.com/elect ... _wiring_6v

[ducwiz]

Did you check that your spark fires at the compression TDC? It is wrongly triggered if the pickup rotor is misaligned by 180°, which results in a spark at the exhaust TDC.

Hans

[weggy96]

Hi Hans
Yes I did and all Ok
David

[blethermaskite]

"before you lose all hope" have you tried to bump start it? when my 350 was dying on the motoplat ignition it would still start on a decent push....just would like you to prove to yourself that it is an ignition failure,.......the cure all depends on how much money you are prepared to chuck at it, probably the cheapest is to convert it to points and coil ignition, otherwise there are a number of aftermarket replacement electronic ignition systems available.
Cheers,
George