take the tank off,you will see the power valve servo unit with four cables running from it.under neath you will see two square boxes,about 3 inches long with plug connectors going to them.just swap the plug connectors over,and if one of the cdi's is goosed.it will swap from the back plug not firing to the front plug,or vice versa.they are not compatable with mc18,mc 21 etc,because they use pgm units .i have seen cdi units for a mc 16 fetch £70 on ebay,and i paid £45 for a pair.
good luck
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i think it wants ringing
i think youve rung its neck.