The drive cog appears to run quite fast,as normal.When the chain is in place and tensioned correctly the chain moves only slowly.The 'kickback' control seems to be working O.K.Oil is in the right places and of the recomended type.The cog that drives the chain under power is a little worn by the the lower part of the chain.Could this and possible chain streach be the trouble?

PETER JOHN SNOWDEN, April 2009