12
Equation for calculating from degrees to millimetres:
α
=
ignition advance in degrees
T
=
ignition advance in mm
R
=
engine stroke divided by 2 in mm
L
=
conrod length in mm
(
)
(
)
2
2
sin
cos
1
α
α
⋅
−
−
−
⋅
+
=
R
L
R
L
T
Downloadable spreadsheet is available on request.
。
remove sparkplug from cylinder head and mount dial gauge in cylinder.
。
find TDC (Top Dead Centre)
。
rotate engine backwards (opposite from running engine rotation) to calculated advance
in millimetres (in example above it is 1,3mm) and make marks on rotor and stator
。
remove dial gauge and install sparkplug back in cylinder head
。
start engine and run at constant speed of 3000rpm to 4000rpm
。
use a strobe light to check alignment of marks on rotor and stator
。
adjust static angle with programmer to align marks on the rotor and stator
Result of above procedure is very accurate static angle.
Important!
。
Static angle is reference point for CDI to calculate delay for programmed ignition
advance.
。
Static angle has to be greater then maximum ignition advance!
。
Example - If maximum advance in ignition map is 30deg, then static angle has to
be at least 31deg.
。
Very large static angles are not a good solution, because it decreases
electronic ignition advance stability (do not use static angle greater then 45deg if not
necessary).
If you find when testing with your strobe light that your timing marks are off by 10 or more
degrees it may be neccessary to reverse the wiring from the reluctor pickup to the ignition and
test again. Reluctor pickups have polarity but it is rarely marked on the pickups so must be
determined by the trial and error method. Incorrect wiring polarity will cause the reluctor
pickup to send the trigger signal on the trailing edge of the rotor instead of the required
leading edge of the rotor.
