ignition issue

T

treoleileagh

Full member
Location
Australia
3C #3305 1976-7
The photo is of the ignition / coil set up.
The bike has strong spark on #2 but no spark on #1 and #3.
I find it hard to believe coils 1&3 would go out together from separate faults. .
Given that nr 2 has such strong spark, and 1&3 that should fire together but are not firing, the problem looks like a single point of failure affecting 1 & 3.
I'm not familiar with this ignition system, where should I look for the point of failure?

Wiring looks good. Plugs are new
Thanks
Chris
 

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I would have thought, or at least my 3c runs a single coil and a double-ended coil. So that's 2 coils for 3 cyinders. Check the later.
 
Under back of tank on early model, you have chock box connections .
Check the wiring diagram ( it's the white, white/red/ black and white/ black wires you're concerned with from the 2 x bosch pickups.


Swap them over carefully ( the latter 2) and see if your problem moves over to the middle plug.
 
treoleileagh said:
3C #3305 1976-7
The photo is of the ignition / coil set up.
The bike has strong spark on #2 but no spark on #1 and #3.
I find it hard to believe coils 1&3 would go out together from separate faults. .
Given that nr 2 has such strong spark, and 1&3 that should fire together but are not firing, the problem looks like a single point of failure affecting 1 & 3.
I'm not familiar with this ignition system, where should I look for the point of failure?

Wiring looks good. Plugs are new
Thanks
Chris
Click to expand...
If u try all previous to no avail, all my issues were down to the CDI generator coil in the flywheel. Overheats and causes issues.
 
Zakredridge said:
If u try all previous to no avail, all my issues were down to the CDI generator coil in the flywheel. Overheats and causes issues.
Click to expand...
Never seen a failed HV alternator coil ( exciter ), truly of the era, cloth bonded and high class enamel wire. Intrinsic impedance of the coil would preclude overload self heating to my mind. It is run in shunt mode regulation inside the HKZ module, ie shorted out in phase aligned ignition sequence. There was the ill conceived engine stop circuit that open circuited the exciter coil, a very bad idea as covered in past posts. Perhaps your coil suffered inter winding insulation or shorted turn, a guess at best.

Gave way to alternate stop relay implemented on the exciter and then later VR pickups. HKZ runs as a zero power demand on the battery, hence the single 7amp single phase alternator coil, feeble to say the least.

Perhaps yours had external issues as on the HKZ the "Battery regulating" bucking coil sits above the HV coil, again well made and never seen a failed one. Possibly have seen and repaired many HKZ oem Bosch setups, including depotting the actual module itself for component level repair. The mini 1 ohm ignition coils were works of electrical art, old Bosch can be impressive...... HTH j.

*** would urge you to search here on failed insulation on the VR pickups cast into the ignition stator plate, early had MuMetal shields latter did not, all have insulation failure at the potted entrance area of the PUPs. 1 and 3 primaries are in series.
 
iis_iis said:
*** would urge you to search here on failed insulation on the VR pickups cast into the ignition stator plate, early had MuMetal shields latter did not, all have insulation failure at the potted entrance area of the PUPs. 1 and 3 primaries are in series.
Click to expand...
From my limited knowledge of triple ignition systems, but based on seeing many posts on here, I'd say Jon is on the money.
 
Hi Chris. I have one of John's ignitions on my 1982 jota, allegedly out of its warranty period. (By about 20 years), still going strong. My 3c had that original Bosch setup which John kindly binned for me. I would probably have enough spare parts here to make up an IIS ignition, but the modern Ignitech from Red in QLD is very good. Most people are running this now.
 
martymoose said:
Hi Chris. I have one of John's ignitions on my 1982 jota, allegedly out of its warranty period. (By about 20 years), still going strong. My 3c had that original Bosch setup which John kindly binned for me. I would probably have enough spare parts here to make up an IIS ignition, but the modern Ignitech from Red in QLD is very good. Most people are running this now.
Click to expand...
hi Marty,
like you guys helped me when I couldn't get my non runner going, I'm trying to help a friend. He bought his bike from its original owner a few years ago but has never got it going. He's run into a psychological wall with it, which is why it's in my shed for a while. He seems unwilling at the moment to throw more money and time at it.
The wiring had been chopped up trying to fix something but I've no idea what. In any case the mods didn't fix anything and the bike hasn't run in decades.
I've repaired the wiring and now it conforms to the wiring diagram and almost everything works (still need to sort out the horns. The fuse blows when the button is pressed). The starter turns the motor and there's spark as I wrote above.
Today, following Rob's suggestion, I swapped the wires and then 1 and 3 fired but not 2.
So it looks like a problem at the alternator. I'll pull it off tomorrow and take a close look. If there is evience of broken insulation outside the pickup potting, I'm hoping application of liquid insulating might restore it.
In any case, if it doesn't do the job and I can't effect a repair, I'll give you a call about your spare parts.
cheers
Chris
 
Vince said:
There is an odd thing about the Laverda Horn wiring, but better someone clever than me goes there.
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Tell me about it Vince, I've rewired mine twice along with fitting the relay and there's still only a 50% chance that both are going to Honk as intended :unsure: and very often fine at standstill but when used in anger not a chance!! :ROFLMAO:......anyway back to topic.
 
The issue with the horn will almost definitely be due to the fact that the LH switch simply earths the relay circuit, ie it doesn't connect a +-+ circuit. I had endless hair-tearing as a very early SF owner after swapping out the Lucas switchgear for ND; I just couldn't get my head around it.
 
If they're kinda working, you probably know, they're activated by earthing. From what I remember, the switch doesn't connect power, it completes the circuit by connecting an earth. One trick I picked up is holding the horn button down while turning that adjusting screw on the horn body in and out. That can allow just enough oscillation to maximise the sound
 
That screw is the tuning, Vince, and not associated with a short circuit - the blown fuse is a dead giveaway. Yes, the power goes to one side of the relay control circuit and the horn button simply completes the circuit to earth, which connects high-amp power circuit in the relay from the battery direct to the horns.
 
Yep, thats why I mentioned Ossalation, I wasn't referring to the Atoms oscillating, just the horn points internally. That screw has resorected my horns a few times. That and drilling out the connecting rivots, replacing them with nuts and bolts and cleaning internally. The screw always needs a fiddle after that clean.
 
Various and numerous HKZ parts here, including a stack of original bosch magnetic flywheels that come up to my knee, ditto many iis spare parts ( component pcb parts ) still in boxes, Marty one of the original users of iis... used to get a sore neck looking up to him, a smile here.

Warm feeling to retain as much of the original equipment on the Laverda, yet reality is harsh, and resounding, should you stop miles from home with a failed ignition. All in all, much of a modern ignition is not visible from the outside, much to be gained in better chance to make it out and back without a concern. Cheaper too, in retrieval costs, the new ignition.

Replacing a HKZ can be done with inductive discharge systems, though the latter is not zero power budget and you will have the decades discussed lack of charging power for the battery. Long box iis was CDI and a power budget of around 1Amp at 12V, inductive discharge around 3-6amps dependent on configuration. treoleileagh will face that question for the owner, the motor runs on the HKZ, for how long. Fix one problem get another. HTH j. ** discussed recently how to chase a dead short, bridge the fuse holder with an old incandescent headlight lamp, gets hot the glass warning.
 
Horns:
Blowing the fuse is a short circuit, possibly even in the horns themselves, try another horn? If it blows the fuse with the horns disconnected there's a short in the wiring somewhere (melted insulation from headers a popular one).
Horns not working is frequently because as pointed out above, there is +12V always at the horn and the button completes the earth. Laverda in their wisdom did not run a dedicated earth wire into the LH switchblock and hence rely on it earthing via the handlebars - triple clamps - steering head bearings - frame. I always run another dedicated earth wire from the main frame earth point, up to the coil plate, and then from there one into the headlight, and one to the LH switchblock. Resolves many issues.
 
It's actually pretty simple, Marty. For something electrical to work (eg light, ignite, beep) the circuit has to be completed. Most of the time the thing that is going to light up, beep or ignite is permanently earthed and the switch just connects or disconnects the + feed. The alternative is to have the + feed permanently connected to the 'thing' and the earth wire is used as the switched interrupter/connector channel. Doesn't matter where the interrupter is, + or earth wire.
 
Schurminater said:
Tell me about it Vince, I've rewired mine twice along with fitting the relay and there's still only a 50% chance that both are going to Honk as intended :unsure: and very often fine at standstill but when used in anger not a chance!! :ROFLMAO:......anyway back to topic.
Click to expand...
As you know Steve I find with no wires going to the horns at all I get a very consistent result.
 
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