Monday, 11 November 2024

FH - ignition timing

 Edging ever closer towards first start, I diverted myself from wiring activities to time the ignition.

Regular readers will know the rocker box isn't fitted yet, and I can tell you that it's much easier to set the engine in position for ignition timing without pressure from the valve springs trying to restrain you.

As I've fitted 7.25:1 pistons to this machine, I am timing it to Cyclone specification - 3/8" BTDC at maximum advance in place of the 11/32" for the home market models. here it is on the ubiquitous Wagamama chopstick, of which I have hundreds:


The timing is set with the timing side piston at 3/8" BTDC on the compression stroke.

With the engine in the right position, I fitted my little clamp to hold the ATD at full advance. The ATD is screwed most of the way on, but is not yet on the magneto shaft taper:

With a green Rizla in the points, I can rotate the magneto until the paper just loosens in the points. It's useful to have a 4 BA spanner available to just hold the magneto shaft on that central bolt while you gingerly tighten up the ATD nut from the other side. With the petrol tank off, it's easy to reach the magneto from the timing side of the bike.

Next, fully tighten the ATD nut. You can then back the engine off and come back up to 3/8" BTDC; if the Rizla is just coming loose in the points (with the ATD still clamped to full advance), you are good to go.



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