Our spies have spotted Triumph's new Daytona 600 being tested with a new 646cc engine.
It was spotted close the the British firm's Hinckley HQ.
The bigger bore is expected to raise power by as much as 10bhp - which could be just what Triumph needs to compete with the latest flock of 600s - including the radical 2005 ZX-6R.
Read more about both new bikes in MCN this week: Click here.
Have Your Say about this story.
Triumph is updating its Sprint ST for 2005 with a reworked engine, updated chassis and styling - including triple underseat pipes.
And there will be a T100 Bonneville - a revamped special edition with a 865cc engine instead of the usual 790cc.