Ignition - Compression - Jetting - Exhaust: A simplified guide for Lambretta & Vespa scooters

Ignition curves can be tweaked and pushed backwards/forwards throughout the RPM range in the pursuit of power. Cylinder heads have endless combinations of combustions chamber design, size, shape, depth, volume, corrected, uncorrected, squish band area, squish gap, squish velocity, and so on. The manipulation of it all can be a bit like a Rubik’s cube, adjust one setting, and watch how it affects all the others. I personally find it fascinating and having owned a dyno, the main thing I learned about ALL two-stroke tuning is, the more you learn, the more you realize how much you don't know! ;)

But for those who are not familiar, or even interested in these intricacies and adjustments, for those who have shied away from even attempting to set any of these important parameters properly, I have put together a very basic guide and suggested a simple setup procedure. I can’t claim this is the ultimate set up, or that it is the most powerful setup, but the steps suggested should make it easier for scooter owners to take more responsibility for their machines, and get involved with the mechanics.

So this video provides what I would outline as a ‘safe average’ which balances power, reliability, and efficiency… and that is no bad thing. There will be things I have forgotten to include, but I’m sure I will be able to cover those items and answer any questions which crop up, when I do the follow-up videos on the practical side of setting the ignition timing, and measuring combustion chamber size, in order to calculate compression ratios. Enjoy the vid

Darrell Taylor's guide to measuring compression: https://www.scootering.com/scootering-classics-compression-ratio/

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