Confused - ignition coil resistance
 

Is the haynes manual correct?

It states primary coil 495-606 Ohms

Secondary 6.66 - 8.14 K Ohms.

I have three coils here for 748, all measuring ~1.0 Ohms primary and 3.2K Ohms secondary

Are they all toast or is the haynes manual wrong?

If there all toast this is good, but I have a sneaky suspicion a new one is going to turn out to give similar readings.

Trying to solve an intermittant misfire, typically occurs under load only, removing nology leads, fitting old leads and closing up plug gaps solved it for three days, only to have it return with vengeance, so ignition seems likely, possibly killed the coils with the nology wires.:(

Possible pick up sensor breaking down or the connector plug has had water in and corroded?
Andy pike had a similar problem which turned out to be a cracked fuse.
Also change the yellow relay and the two relay's under the seat.

I'v also downloaded a ducati workshop manual and the haynes manual is infact incorrect.

Primary coil resistance should be 0.495-0.606 Ohms

Secondary 6660-8140 Ohms.

Which makes much more sense, so just my secondary windings are a bit low, but not necessarily the problem.

Pick up sensor sounds a good one, The plug is all nice and clean, but could well be worth getting another sensor.

Will change the relays too.

I'v got her in bits at the moment to change the cam pulley bearings, check valve clearances after I adjusted them last year and sort this annoying problem, ready for some new rubber and a summers fun, taking her to le-man for the 24 hr, so need her to be reliable soon!

Check the air gap on the pick up sensor. Seen a few that return good resistance values but the gap has been too wide. Aim for the tighter end of the install values. About 0.6mm :)

I will, but why should it all of a suden become a problem? Been running well with the gap its at for years.

If the sensor is starting to break down with age then it can't maintain sensing the original air gap of say 0.6mm. So effectively it's like the gap has widened so setting the gap to say 0.4mm may or may not help, but has to at least be worth checking.

I'm with you know, thanks

So far the relays mentioned all check out ok, and resistance of pick up is good. although obviously this is all with out heat or load.

Checking air gap next.

Help is much appreciated, thanyou

You mention closing up the plug gaps helped, have you tried new plugs
Maybe we should pluging my Diagnostic on

Not yet, and they are fairly old but not excessive mileage, dcpr9e's, which from what I understand, will be harder to spark wih a struggling system than iridiums.

What I do not want to do is mask the fault from myself, only to have it show up when I get off the ferry!!

Diagnostic is a thing dreams are made of, that could prove very usefull.

I currently have her in bits, I intend to check the valve clearances I adjusted last year on saturday, then re-fit belts and pulleys that are off for new bearings as they are very old.

My money is on a blocked fuel filter at the moment, as I have not changed this for far too long. This will get done sat also and everything in tank checked out, after this I will fire her up and see where we're at.

Being able to read fault codes would be very usefull. Could you let me know when you might be available for this please:)

Just found a pretty well blocked fuel filter, split hose between pump and filter and rather dirty fuel pick up screen.

Fingers crossed