08ex4
07-30-2009, 05:36 PM
please help i have an 05 400ex and its started smoking the other day, really bad through all rpm's. the smoke smells like unburnt fuel not oil the plug is black but not wet and it doesnt smell like burnt oil and it still has plenty of power its completely stock and ive heard they are a little rich stock so that would explain why the plug is black. its not tapping and i checked the valves and they are good no need for adjustment. could it be that the spark is weak and not burning all the fuel that is dumped into the combustion chamber therefore blowing the unburnt fuel out of the exhaust as a smoke. like i said the quad is bone stock with about 30 hours on it. thanks to anyone that can help.