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rocker's picture
VBMWMO #9315
Joined: 08/23/2017
Posts: 6

OK, schrader7032 replied and that was helpful, but the crankshaft has to be in a certain position when the magneto rotor is tightened down or the spark timing will be way off. All I have is an old Clymer manual and it is pretty vague at times. Any helpful hints? Thanx!

schrader7032's picture
VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6896
The engine must be turned so

The engine must be turned so that the S-mark is in the timing window. Then the rotor is installed on the camshaft. The rotor has two marks on it, 180 degrees apart. One of the two marks need to show in the small v-notch at the top of the magneto body when the rotor is installed.

Note that is for timing of the magneto. Then you must do a separate process for timing the ignition. It also uses the S-mark (which kind of confuses people). The points gap is adjusted to around 0.016" at a point when the points are open their widest...that is when the points rubbing block is riding on the high point of the advance cam. Once the gap is set, then the engine is turned and the points should open when the S-mark is in the middle of the window. If the S-mark is not aligned right, then the points timing adjustment is used to change when the points open.


Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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