take the plastic cover off the side of the engine and clean the flywheel magnet things and the pickup magnet things really well regardless of how clean it looks at first.
I lost my sparks and went twatting around trying different PGMs and wiring harnesses and trying to find damaged wired etc etc with no success. Then someone randomly suggested cleaning the pickups and flywheel and im all like; they look clean to me, what good is that gonna do?! But sure enough it worked a treat and i got good strong sparks after that.
Worth a try as it takes no effort or cost.
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After years of moaning about immigrants now i am one...