2007 Signs to make a surprise MotoGP comeback, at the age of 42, for the new Ilmor SRT team, despite breaking his left femur during testing with the team at the end of 2006. An accident during practice for the Qatar season opener rules him out of the race, which turns out to be Ilmor's last of the season - and probably ever - after 'financial problems'.
2006 Occasional AMA Formula Xtreme outings for Buell, asked to test for Ilmor at end of season.
2005 With Aprilia withdrawing from MotoGP, McWilliams finds options limited and opts to sign for Paul Bird's Stobart Honda team for an attack on the British Superbike championship. However, partly due to shoulder injury, the season proves a disappointment and he misses many races. When he excepts the chance of a one off ride for Team Roberts in MotoGP following its split from KTM it is clear which championship his heart is in.
2004 Signs to ride the Aprilia RS Cube in MotoGP alongside Shane Byrne. Finishes 19th in points during a difficult season in which financial problems at Aprilia mean that the MotoGP bike is virtually undeveloped.
2003 Remains with Proton Team KR. Starts season on KR3 after delays with the team's new V5 four-stroke. Turns heads with some gutsy rides on both machines, but reluctantly leaves the team at the end of year after tyre supplier Bridgestone remove their support.
2002 Moves to MotoGP with Proton Team KR riding their 500cc triple against the four-strokes. Highlight of the year a shock pole position at Phillip Island. Finished 14th in championship with 59 points.
2001 Continues with the Aprilia Team but in the 250cc category - finishes sixth with 141 points.
2000 Returned to the 500cc World Championship scoring 76 points. Classified 14th in the standings.
1999 Tenth in the 250cc World Championship with Aprilia.
1998 Ninth in the 250cc World Championship.
1997 Tenth in the 250cc World Championship after making his debut in Malaysia.
1996 16th in the 500cc World Championship.
1995 19th in the 500cc World Championship.
1994 12th in the 500cc World Championship.
1993 Made 500cc World Championship debut (AUS). Finished 21st in the overall standings.
1992 Competed in the Championship of Ireland and Open and British Supercup 250cc Championships.
Also race in the European 250cc Championship and the British 750cc Supercup.
1991 Won the Championship of Ireland.
Won the British Supercup 250cc at Brands Hatch.
1990 Won the Championship of Ireland, open 350cc race.
First in the Championship of Ireland ''Yamaha Powervalve'' 350cc.
1989 Raced in the World Championship of Ireland 350cc and the Championship of Ireland, production 350cc.
1988 First in the Championship of Ireland, production, 350cc race.