Will changing spark plugs cure a misfire?

Published: 17 August 2010

Q. My Ducati 900SS has a misfire which starts after I have ridden a few miles. Will changing the plugs sort it out?
George Booth, email
 
A. A misfire is either related to the fuelling or the ignition, so you do need to start with the plugs. But instead of just changing them, get hold of a spare set and the tools to replace them when you go out next.

As soon as the misfire starts check the plugs. If they are black or sooty, there is a problem with the fuel/air mix such as the choke sticking on. If the plugs are wet, there may be a problem with the electrics.

Fit the new pair of plugs when you check the old ones. If the bike runs fine, suspect the ignition and get it tested thoroughly.