Some advice would be much appreciated
I'm new to this awesome sport, and loving it, I have just purchased a 2010 sherco st250 which mis/back fires
I know of another rider with a 2010 290 and his appears to do the same.
Will it do damage to anything/engine?
Will he laugh at me being for thick?
The bike seems to run well once started which is never a problem, plug looks fine to my eyes, I notice a change in spark plug from 2009 model could this be worth checking?
Many thanks for any views on this matter
John














