Would a faulty exhaust flap valve cause a big loss in power? Been out for a 50 mile ride this morning and all was fine till the last 10 miles when I only just managed to get home. Seems like a fueling issue/gutless and no power especially at low revs and when been off the throttle sometimes will clear itself when reving hard. Managed to get home to then notice a burning smell and smoke coming from the exhuasts. They were crackling for ages when I switched off as they cooled down. Was just wondering if it's the exhuat flap valve not working correctly. No error codes or anything at all showing on the dash.
Exhaust valve being closed will cause it to bog down once into the revs rather than at slow speeds so possibly not that sadly
Have you still got the cat in the exhaust system? If so, what you have described sounds like a faulty spark plug or coil ie no or intermittent spark on one cylinder, causing the sensation of a loss of power/gutless (most likely just the plug as there’s no EML thrown). However, the injector keeps feeding fuel into the cylinder, it’s not burnt there, gets ejected into the exhaust system and collects in the cat where it catches fire and quite possibly is the cause of the burning/smoke issues you experienced. You really don’t want a fire in the cat as a) they get super super hot and b) it just destroys them. Id let the bike fully cool then start the bike and, carefully, touch each exhaust header, you’ll soon know if one isn’t firing, it will remain cold or cooler. If so replace that cylinder’s spark plug as a start to solving the problem (admittedly the horizontal plug is a pita to get at ).
Yes cat will still be in the exhaust as its a standard stock exhaust system. Definitely did seem as though something was burning in the exhaust and it had obviously got way hotter than normal with all the noise it was making when cooling down. I did start the bike again after several minutes and it started fine. But now it's been stood for a couple of hours cooling down outside its refusing to start. Turns over fine and almost fires up.
