Thought I'd return the favour of gleaning tech.info. from here by sharing a fix with you all...Son's Bravo S got sick ,and we replaced Spark Unit and Leads... fine for a while,(it was knackered as Plug three was non firing)......then it got the glitch of flat spot,fluff,power loss...cured it by unplugging all multi Connectors as I suspected dry joints(you lose the connection on one or more contacts),sprayed in WD, although Duck Oil probably better...and now it's running like a dream....cold wet short trips included.As a retired auto engineer I'm impressed by this engine..really quite rapid, with a nice intake/exhaust howl......