Ignition Failure when Hot

Dear All,

I have a 1998 750SS which has developed a fault.

When properly hot, 20+ mins ticking over or riding around central London, the front cylinder stops firing.
If I leave it to cool for 5 mins all is ok again - for a while!

It is definitely lack of spark not fuel but I have swapped over coils and CDi units between cylinders and replaced HT leads with no effect.

Any ideas?

Regards,

Steve A

Steve.
It’s probably the ignition pick-ups, I think that year they are still two of them mounted under the left hand side cover?

Kevin.

If that’s the case Electrex do replacements at fair money (I know because a friend recently needed a set for his Elefant).

Yes Michael, that’s were I got them from for our 600 Monster, this is a link to them on Electrex World.
http://www.electrexworld.co.uk/acatalog/P8.html#tab_aP8_0
I was going to buy the originals from Ducati with the correct connectors etc, but I don’t think that they are available.
So I used these and bought new connectors that fit the Kokusan CDI units, I think I had to extend the cables up to the CDI boxes, I’ll have to have a look at what I did later, and where I got the connectors from?
Kevin.

OK, I’ve found the info out:
I did have to extend the Brown & White cables form the pick-up to reach the CDI units, so I did the following:
Make a note of which pick-up is which the Left hand one (I think) has a RED and a WHITE cable, the Right hand one has a YELLOW & BLACK cable, see sketch.
I bought some matching colour cable from http://kojaycat.co.uk/ with some through crimps and some heat shrink.
I extended the cables using the trough crimps matching the colours and heat shrunk them with tubing, remembers to stagger the crimps otherwise it ends up in a blob in the middle of the loom, fit the pick-ups onto the engine, then feed the cables out through the gland and crimp the new 2 way connectors on the other end so these plug into the CDI units.
See attached pics etc.

[attachment=1]Ignition Pickups Colours_Page_2.jpg[/attachment]

[attachment=0]Kokusan Connectors 600 Monster.jpg[/attachment]

Kevin.

[attachment=1]2013-11-16 001.jpg[/attachment]

[attachment=0]2013-11-16 003.jpg[/attachment]

…and that’s how it’s done. Tadaaaaaaaa!

Fault Found…

You were so right - thanks Kevin.

Multimeter confirms pick-up for front cylinder goes to open circuit when hot.

Thanks you all for your replies and advice - repair in hand.

Steve A

That’s good, sorry I should have suggested testing each pickup with a multimeter for resistance, they should be about 100 Ohms, so I assume one of yours is open circuit ie infinite Ohms, or a very high reading.
Although if it only does it when hot it’s catching it when it’s doing it.
You can just unscrew the pick-ups and replace them without disturbing the timing plate, just 4 x M5 Allen heads
I also re-used the black braided sleeving inside the engine for protection.
Let me know if you need any more help or photos etc.

Kevin.