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BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: WojtekPoland on 07 Apr, 2025, 15:34

Title: Ignition timing versus 98 octane gasoline
Post by: WojtekPoland on 07 Apr, 2025, 15:34
Hi everyone
I wonder should I set ignition about 5 deg. earlier because of using 98 octane gasoline. My bike is BSA A65 Lightning 1968.I do not know wat was gasoline octane number in UK in 1968 but in Poland was 78 octane.
Thx for any answer
Best regards Wojtek
Title: Re: Ignition timing versus 98 octane gasoline
Post by: DAVE BRADY on 07 Apr, 2025, 17:03
Hi Wojtek,


I run a '68 Thunderbolt at 34º and it is fine with today's fuel. I also have a long stroke 750 A65 and use standard A70 timing of 38º.
Start with the standard timing of 34º BTDC fully advanced and see how the bike runs. If necessary retard it a bit to get better running.

Dave.
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