Looking for simple ignition wiring diagram for 65 Jubilee

J

JackG

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Jun 24, 2022
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Hi all,
I've recently acquired a '65 Jubilee with partially burnt out and damaged wiring and bits, that I'm restoring.
I've ordered a complete new reproduction harness specifically for the Jubilee, but because of the damage, I've not been able to try and start the engine to see what that's like, before dismantling everything.
And I wouldn't like to install the new harness to try and get it running, only to take it all down again to do the frame.
Does anyone know where I can get a simple ignition wiring diagram so that I can jerry rig something to just test the components and try and see if the engine fires?
I've looked at the complete wiring diagram for the Jubilee but I'm afraid my electrical knowledge is way too dismal to decipher what I'm looking for., especially that it's a twin.
Appreciate any help on this
Thanks.
 
Wire from battery live, to one terminal on each ignition coil.

Wire from other terminal on each coil to a pair of points.

Kick over, with spark plugs sitting on the cylinder head. Should see sparks.

You may be able to discern that a plug is sparking when air is blowing out of its cylinder’s plug hole. Otherwise you’ll be randomly swapping plug leads around to get them right.
 
Thanks for the quick reply TT
Would it be enough to fire the engine with a bit of fuel? Apologies for the obvious ignorance.....
 
JackG said:
Thanks for the quick reply TT
Would it be enough to fire the engine with a bit of fuel? Apologies for the obvious ignorance.....
Click to expand...
Yep
Rig up a dummy tank with fresh fuel for best results
Never worry about any questions you ask here , nobody was born with all the answers
Hopefully it'll fire up
What carburettor does it have?
Monobloc ?
 
JackG said:
Really appreciate the help guys, will try this evening and see how we get on
Yes, monobloc carb
Click to expand...
Ok
Depending when it was last run its possible the pilot jet could be blocked
Luckily it's easy to remove and clean on a monobloc as long as a previous owner hasn't mullered the screw driver slot on the jet
But give it a try first before delving into the carb
Tickle it until fuel only just floods out
Probably won't need the choke this time of year if one is fitted?
 
Well big move forward, thanks to you guys. I have a spark!!!
Couldn't get it to fire yet though. Took the plugs out, no smell of petrol, so I don't think I flooded it.
But also the points have almost no gap. The adjustment screw on the points has been ruined so couldn't move those either.
I think the next thing would be the carb and the points to sort out.
But I have a spark!!!
 
The Jubilee is very sensitive to points gap and condition and ignition timing.

Sounds like you’re not tickling the carb nearly enough.
 
JackG said:
Well big move forward, thanks to you guys. I have a spark!!!
Couldn't get it to fire yet though. Took the plugs out, no smell of petrol, so I don't think I flooded it.
But also the points have almost no gap. The adjustment screw on the points has been ruined so couldn't move those either.
I think the next thing would be the carb and the points to sort out.
But I have a spark!!!
Click to expand...
If you get desperate you can squirt some lighter fuel in the carb (open the throttle wide while you squirt it in ) or in the spark plug holes
Then see if it fires
If it does you will know it's a fuel problem
 
Probably right on the tickling. Couldn't get it to fire at all, despite the spark. I'll be trying again, but I think the points are a problem too. They don't look right.
It will be a struggle to get them adjusted though, the screw looks more like an allen key than a philips.
 
JackG said:
Probably right on the tickling. Couldn't get it to fire at all, despite the spark. I'll be trying again, but I think the points are a problem too. They don't look right.
It will be a struggle to get them adjusted though, the screw looks more like an allen key than a philips.
Click to expand...
You need to tickle until fuel is on your finger/carburettor wet with fuel
Especially for the first start
 
JackG said:
Thanks for the link to the wiring diagrams, but as mentioned in my first post, they didn't help.
Click to expand...

If you have the same Jubilee and Navigator wiring diagram then it shows a single ignition coil and one spark plug also a distributor that the Jubilee (and Navigator) as far as I'm aware didn't have but had twin 6V coils and points.
 
So, tried squirting fuel into the cylinders, also in the carb, I think it tried to fire a couple of times, back through the carb, but couldn't get anything positive.
But I checked the spark again and realised I only had a spark on one cylinder. Swapped out the plugs, HT leads and the wires from the battery and it seemed that one coil was faulty.
Tested both and got the same readings from both of them 2.3 ohms and 8.78 k ohms, so not sure what's going on. Very strong spark on one and nothing on the other.
One thing I just thought of though, I have a positive connection from the battery to one terminal on the coil and then from that coil to the other coil - not two separate connections from the battery.
Would that be a problem? Looks like that was the way it was wired originally.
 
JackG said:
One thing I just thought of though, I have a positive connection from the battery to one terminal on the coil and then from that coil to the other coil - not two separate connections from the battery.
Click to expand...

The standard electrical system is positive earth so the battery wire to both coil negative terminals should be the battery negative wire.
The coils would not normally be connected in series but each coil positive terminal would connect to a set of points as I don't think the Jubilee and Navigator ignition systems were much different to the Electra except for the Electra having a 12V electrical system although I could be wrong as I can't find any information on the Jubilee's ignition system.
 
Last edited:
The Jubilee's ignition system diagram showing a single coil, one plug and what's marked as a "Distributor" makes little (ok, no) sense to me, but perhaps it does to our other members?
Looking for simple ignition wiring diagram for 65 Jubilee
 
I think you are right on all counts. I see a Jubilee/Navigator diagram on line that shows positive earth with two coils and what looks like one distributor/points(?)
The bike currently has a negative earth and some very dodgy looking home made wiring, which is probably why it all burnt up in the first place. I'll redo it tomorrow with a positive earth and individual connections from negative to the coils. Really appreciate the advice, hope I haven't blown anything up in the process so far.
 

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