Wonder if anyone can give any advice before I go off on a wild goose chase. Got a chronic misfire that started as a blip in high gears when bimbling and then accelerating gradually round town up to about 2k rpm. Now its got really chronic in all gears but clears in 1st to 3rd when it hits just over 3k rpm.

Got new plugs and air filter. No air leaks anywhere but one HT lead looks slightly dodgy at the outside of the cap in the plug recess. The plugs are only 4 weeks old and the fifth plug looks slightly fouled.

Before I go off spending £50 unnecessarily on HT leads, anyone got any other suggestions?

Cheers
Rob