I was talking to this dude who used to work for Honda recently (he took the first CB750s out of their crates and assembled them - fitting the revised resevoir and mastercylinders as he went back in 1969/70 - very interesting bloke! he prepares his son's Ducati 250s for classic racing now) Apparently the little magnet things on the flywheel should be polished so they are clean and shiny (the rest of the flywheel is unimportant) for the signal to get to the pickups properly. My bike decided to lose its spark again the other day (after starting first kick everytime for a a couple of days) but cleaning the flywheel magnet things with meths and cloth temporarily resurrected it again - once it has fired and started running everything is faultless and happy.

I'm gonna do as he says and see if that makes it last longer. Just thought i'd share this incase anyone else gets a mystery lack of spark at some point!

Has anyone else had this problem?
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After years of moaning about immigrants now i am one...