Misfire when electrical system connected

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morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Misfire when electrical system connected

Post by morini_tom »

Odd one here got me scratching my head. Misfire on recently acquired K1 which I have now traced to the electrical system (not the ignition system!) but I cannot understand why as they should not be linked.

I pulled the green wire to the ignition switch from the fusebox and rode with no key. Perfect fault free running. Misfire is repeatable with the key in the on position even with the green wire still pulled from the fusebox.

So I bypassed the ignition switch completely by pulling all its wires from the fusebox. Again, perfect running with all wires unplugged from switch, however when I bridge the red and brown wires in the switch loom (as per the ‘on’ position) the misfire repeatedly returns.

I can’t understand what would be linked between the ignition circuit and the rest of the electrical system.

I have a 5 wire alternator;

-green to fuse box connected to greens from ignition switch, kill switch and transducers.

- 2 yellows to regulator

-Red to fusebox hot side

-white to fusebox connected to white wire to both transducers.

The regulator has the 2 yellows from the alternator, brown to the switched positive side of the fusebox and then an additional red which is not shown on the wiring diagram to the hot side of the fusebox.

Regulator is a Ducati energia 343152

Probably pointless trying to provide photos of the wiring but I've unplugged all the top connections to give a better view of the bottom & regulator.

Any suggestions gratefully received
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mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Misfire when electrical system connected

Post by mbmm350s »

Hi Tom
I think I would be checking the engine earths, the regulator earth and the transducer earths.
Another possibility could be some kind of partial short or weak insulation in the wires to the stator the yellow wire connections are often close to the green connection.
I once removed a stator from a machine and the loom was full of oil :shock:
Mark9
George 350
Posts: 450
Joined: 16 Jun 2007 09:43
Location: Northampton

Re: Misfire when electrical system connected

Post by George 350 »

Hi Tom,
K2 is too modern for my Morini knowledge, but could there be a link between the kill switch and the starter switch?
Just a thought...
Regards, George.
George
350 sport 1978, 350 Strada 1978
650 Norton 1967, 650 Kawasaki 1977 and 650 Enfield 2019
morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Re: Misfire when electrical system connected

Post by morini_tom »

Thanks for the suggestions,

I don't like fixes where you change loads of stuff and never really know what fixed it! However, I have just come back from a 10 mile ride (yes, in the dark!!) with not a hint of misfire.

-I replaced all of the earths and scraped the frame paint off even more (which in fairness all looked ok before) and ran some extra earths from engine to starter relay bracket and to regulator case.

-I removed the fusebox, thoroughly cleaned it and replaced 4 rivets which were okay but were allowing the terminals to wobble a bit. I also tightened up the floppy fuse holders.

-I removed the red wire from fusebox to regulator (which I believe was redundant anyway)

-I cleaned all of the spade connectors and tightened a couple up.

-I tidied up the wiring to the fuse box.

Didn't need to lift the tank or go anywhere near the pickup or transducers.

Feels good to be back on a happy 350!
norbert
Posts: 750
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: Misfire when electrical system connected

Post by norbert »

That sounds good. So any of the thinges you did, did it :P
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Misfire when electrical system connected

Post by mbmm350s »

Hi Tom

Great!

I have a great suspicion of the fusebox - it's a really evil thing.
Its not necessary and with some thought can be removed completely
and replaced with a simple blade fuse box and terminal strip.
I cant imagine Norbert would tolerate the fusebox :D :D

Mark
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: Misfire when electrical system connected

Post by 3potjohn »

Good result. At least you can get to the fuse box easily enough.I have put some 3M adhesive film on the inside of the side panel as a hedge against cables rubbing bare metal. In your photo I was amazed as to how clean the wiring looked, mine is usually covered in what a publican once referred to as “road dirt” just before he threw us out. I have removed and tidied wiring from my K, especially from the rear as there seemed to be an over provision. Dirty connectors or corrosion within the wire ends are a worry. You cannot beat getting the correct coloured wiring from vehicle wiring products when you need any.
I think the K may be the best one.
John
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