Bantam D14/4 ignition timing

[Y13 Alan G]

Is there a piston distance before TDC in mm, or inches, that I can use to accurately set the ignition timing rather than using a dial gauge at 16.5 degrees BTDC. Hope someone has the answer.

[JulianS]

See below from D14 workshop manual.

[AdrianS]

There is a measurement but I cant remember what it is.

It can be worked out by drawing a circle with the diameter the same as the engine stroke. Then draw a vertical line through the centre and with a protractor draw a further line 16.5 degrees from the vertical line in both directions. Join these 2 lines and measure the distance from the top of the circle to where the horizontal line crosses the vertical line ( if you can understand what I mean!).

Finding TDC can be a pain. you need a vertical measure and you need to mark a point on it before it gets to TDC (say 5mm)
Mark this on the flywheel with a reference point on the crankcase.
Go past TDC and again mark the flywheel when the vertical measure is at 5mm.
TDC is half way between these 2 points.

[Y13 Alan G]

 Hi Julian. Many thanks. Alan