Jota 180 CDI ignition problems

You just reminded me of something John. When I was troubleshooting an ignition problem on my Benelli triple, I found all the coils to be open circuit on the HT side. I was expecting a few K Ohms, but not infinite resistance. But two of them were still firing OK which was a bit of a head scratcher. I thought maybe there were breaks in the coils' internal wiring (causing the meter to not see any continuity), but the spark current was jumping them like it does with the spark plug gap. Does that sound reasonable? They're coil over plug stick-type coils.

I bought new coils but it made no difference to the one that was misfiring. The fault, when it was eventually identified, turned out to be elsewhere.
 
Dellortoman said:
You just reminded me of something John. When I was troubleshooting an ignition problem on my Benelli triple, I found all the coils to be open circuit on the HT side. I was expecting a few K Ohms, but not infinite resistance. But two of them were still firing OK which was a bit of a head scratcher. I thought maybe there were breaks in the coils' internal wiring (causing the meter to not see any continuity), but the spark current was jumping them like it does with the spark plug gap. Does that sound reasonable? They're coil over plug stick-type coils.

I bought new coils but it made no difference to the one that was misfiring. The fault, when it was eventually identified, turned out to be elsewhere.
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Very correct Cam, the machine to human infection is well known, a small problem on the motorcycle produces a rare though not well understood condition of scalp irritation. Can also in Australia migrate to the nether region at the rear, when near these mechanical faults or symptoms. Producing a scratching motion which does nothing to solve the actual mechanical fault, though does provide a degree of relief for the irritations. However if the fault continues, then an itch-scratch cycle is produced until the symbiotic condition is broken, fix the fault or stop scratching..... yes indeed am a worry in many a form..

Open circuit gap on HT winding, little else to explain away the lack of predicted reading, have seen high inductance produce erroneous reading ie jumping around display on low cost DMM ( even high cost ), can only proffer the actual resistance reading is done with a variable DC condition internally on the DMM, in the cupboard here are two AVO moving coil meters AVO 7 and 8 ( mk version escapes me ) these old timers are a fall back to perform measurements that have known technical measuring parameters.

The Benelli coils would have some reason and still working, measured O/C, sure it was not a welcome part of the diagnostic process, another known parameter, being derailed onto a track that leads to nowhere near the fault or faults....

Off to a gig today, sharing the stage with a Trad Jazz Band.... we are Rockabilly... how it is these days....bye for now, j
 
CLEMTOG said:
I too have also sent one to him, but not heard if it arrivede the next day which it should have.
CLEM
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Hi Clem,

I hope you received my reply. The CDI arrived on Wednesday. Almost the same time as the one from Dave. Thanks for your help. I’m hoping to have a day working on the bike tomorrow, so fingers crossed.
 
Sorry for the delay getting back. I finally had some time to work on the Jota yesterday. I decided to resleeve all the pick-up wiring as even the best had hard insulation, whilst also moving the stator plate slightly to equalise the gaps on the pickups I have also replaced the famous connector under the tank, removed and cleaned up all the earths and fitted an extra earth strap to the case of the CDI received from Dave, which is now fitted. New B8ES plugs and 115 degree NGK caps fitted with new 7mm copper core HT leads. At first, I wasn’t sure it was going to start, but after a few prods on the starter it started to fire and soon after came to life with all three cylinders playing that magnificent 180 tune. Planning to take it for a run at the weekend now to clear the cobwebs. Thanks to everyone for your help and especially 78Jotadave and Clem for sending me parts. Clem, I haven’t used the CDI you sent me. I am happy to return to you if you wish or I can hold on to it here and if anyone else is in trouble in the future, I can send to them. Just let me know. Thanks Pete K.
 
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