During the War...... Back in the early 1960's the ignition timing on Parilla S13 and BA13 was 1.5 mm btdc. These engines did not rev more than 10,000 rpm. It was not until Rotax introduced modern 'proper' con rods that revs went up. The motoplat on a BT82 (16000 rpm) is up to 3 mm btdc. If you put a stobe on the ignition there is a small advance from 1000 to 5000 rpm. the PVL exibits a similar effect. A mistake in initial manufacturing has the PVL timing as 1.5 to 2.1. My best PVL 100cc BT82 engine ran best with the ignition set back to 1.6 mm btdc, but did not suit other BT82's. So you test test test. I cannot remember if I did check the ignition timing on the ICA motors that reved to 20,000 rpm as these motors were rebuilt every meeting, but I think 3mm btdc was about it as the rev range was from 8000 to 20,000 fixed ignition timing.
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