Ok so the bike idles perfect starts perfect, but when its revved it is misfiring, carbs have been off and cleaned and set up 4 times now, plugs look good no fouling, new battery on it, fuel pump is working fine, engine had a full rebuild all new rings etc.
It's starting to do my head in now, anyone help please?

here is a video of what its doing
https://www.facebook.com/photo.php?v=10 ... =2&theater

I had a similar problem some time ago it drove me mad.


In my case there was a tiny crack in the insulation ( needed magnifying glass to see it) the surround the core electrode of one of my plugs it would run ok at no load at low rpm.

A new set of plugs fixed it.