Richardson has won eight times at the Pre-TT Classic since 1988
Roy Richardson claimed his second victory at this year's Blackford's Pre-TT Classic Road Races on Monday.
The Blackpool racer piloted his 476cc FCL Aermacchi to a 10.429 second victory over Mike Hose in the 500cc Senior race at Billown.
Jamie Coward completed the podium places on his 375cc Honda.
Hose had earlier won the day's opening Lightweight race on his 250cc Ariel Arrow, finishing 1.5 seconds ahead of Peter Wakefield.
Dave Edwards completed the top three with Saturday's 83-year-old winner Ted Fenwick ninth on his Ducati.
Meanwhile, Vincent and Phil Biggs took a commanding victory in the sidecar event.
The duo finished 1 minute, 38 seconds ahead of the local team of Eddy Toombs and Bob Dowty with Ian Salter and Tim Dixon three seconds back in third.