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How to check ignition timing with a strobe light?

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How do you check the ignition timing of a light twin, in this case a Jubilee, without a timing mark to go by? I am not aware of any timing mark on these engines.

I have installed and set up a Pazon system successfully on my Jubilee but the instructions recommend a final tweak using a strobe light; that's fine for a Triumph with a timing mark on the alternator but what is the reference point on a Norton light twin?

Regards,

Dennis

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Type in AO Services. Click on the orange triangle top right corner. The menu on the left should give you some of the info you require.

John.

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I attached a timing disc to the rotor ( removed the nut, fitted the disc - printed off the net and stuck to card - and then refitted the nut) and using a dial gauge set a pointer to tdc, it is possible even though the plug hole is angled, but easier if the head is off. Once youâve done that all you need to do is point the strobe at it!

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If only my magneto-ignition bikes could have permanently fitted and timed degree markings!

Paul

Previously Dan Field wrote:

I attached a timing disc to the rotor ( removed the nut, fitted the disc - printed off the net and stuck to card - and then refitted the nut) and using a dial gauge set a pointer to tdc, it is possible even though the plug hole is angled, but easier if the head is off. Once youâve done that all you need to do is point the strobe at it!

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I doubt if Dan leaves the timing disc permanently attached ? I only mark TDC and 32 degrees on the rotor using Tippex and a corresponding Tippex mark on the pointer. The tippex really shows up brilliantly in the strobe flash and you can see the white dot move as you rev.

The big problem of course is the aggravation of having to remove the primary cover to get to the rotor. It should be possible to cut a neat access hole with blanking plug in the outer cover if you are a dedicated engineer and then you can check your timing every week !.

Patrick

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Many thanks for the replies. Shame I fitted the chain case cover before asking the question Cry

However, it has given me an idea. I installed the Pazon system and timed it with a timing disc so the alignment 'dot' on the trigger magnet is at 32 degrees. If that is accurate, the 'dot' should only show through the alignment hole in the pick up plate when it is at 32 degrees. I 'll see if that shows up under strobe light.

To adjust the timing finely with the Pazon, the pick up plate is rotated so if the dot is not aligned with the hole precisely the plate needs moving.

I'll give it a go and see what happens.

Dennis

 


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