Ignition timing twins - question

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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Ignition timing twins - question

Postby electrajohnt » Sun Feb 09, 2020 2:48 pm

Hello. Help again please.

I would guess the following confusion is mine but some explanation would help please.

Confusion 1).

In the workshop manual for the 1960 models. Page 18 deals with re-timing the ignition.

The text deals with finding the correct 11/32" position btdc for the right hand cylinder (offside cylinder). Then, the positioning of the distributor (using Fig 5 as an example) indicates the distributor should be installed in the position shown, that is appropriate for the timing of the left hand cylinder.

This method seems to be setting the timing for the left hand cylinder with the right hand cylinder in the firing position.

Confusion 2) - well maybe not, this seems correct.

In the Technical Tips section.(Twin Timing by John Allen).

The text and method is virtually the same as above but he states the rotor should be in the three o clock position. This seems to be right, is that so?.

I have looked if anyone else has been confused by the workshop manual, I can't find anybody who as posted a comment, so apologies if my query is so bland Has to not warrant comment.

Regards
JohnT
JohnT

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Re: Ignition timing twins - question

Postby McBob » Mon Feb 10, 2020 4:01 am

My take on this, choose the easiest cylinder for you to measure, does not matter with a parallel twin (all being well).

Remember to have the rotor at full advance, if it lines up with the caps terminal then the spark is off to the plug.

If it is the wrong cylinder, just swap the leads.

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Posts: 64
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Re: Ignition timing twins - question

Postby electrajohnt » Mon Feb 10, 2020 10:27 pm

Hello McBob
Thanks for your advice.
JohnT
JohnT

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