The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Jonah on 23.06. 2025 16:15
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1960 A7 Steel Head single carb
I had a magneto refurbed bike ran and started perfectly, 2 years in magneto had a failure fixed under warranty and produces spark .
Done all usual checks plugs leads etc
I
m sure timing is correct but bike wont start and only backfires , Im worn out kicking
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The old "swap the plug leads over" tip?
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Hi thanks , Ive done that but thank you
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did you time it at full advance ? manual mag or auto advance?
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Bike now starts but only on LH cylinder RH misfire , its magneto with no manual advance retard
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You still have to advance the automatic mechanism before setting the timing.
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Is it possible that the magneto slip ring has moved or is a bit loose. Mine did and had your symptoms.
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Is it possible that the magneto slip ring has moved or is a bit loose. Mine did and had your symptoms.
Do you mean the cam ring?
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Is it possible that the magneto slip ring has moved or is a bit loose. Mine did and had your symptoms.
Do you mean the cam ring?
yes I do
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Have you changed the plugs?
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you dont mention the plugs your running I had a few problems similar with NGK swapper to Champion C4 problems went away , check compression , points gap, ......take bike in a dark shed spray bottle of water and spray the HT leads and mag cap see if your sparks going to ground
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you dont mention the plugs your running I had a few problems similar with NGK swapped to Champion C4 problems went away , check compression , points gap, ......take bike in a dark shed spray bottle of water and spray the HT leads and mag cap see if your sparks going to ground