Winfield Racing team owner Roger Winfield is battling against time to get John McGuinness on the grid of Saturday's 500cc Senior Classic TT with a competitive bike after the engine of the Paton twin nipped up in qualifying. Although the engine didn't blow up, it persisted in blowing oil out of the breather, and Roger decided to change engines.

"We're putting the engine from Conor Cummins' bike into John's machine, and we'll put an engine from a bike that we have here for sale into Conor's Paton," Winfield said. "Before Conor joined the team, we agreed with him that if there were bike problems, John would take precedence."

Winfield have won Classic Manx GP races with their Patons, and the Phillip Island Classic in Australia with their 1100cc Harris Yamahas. But since the Classic Manx GP became the Classic TT in 2013, the Manx fairies have frowned on the team. McGuinness has yet to finish a 500cc Classic TT in three years of trying on the Paton. "It's always a drama here," Winfield said.

It is for other people, too. Michael Rutter's Ripley Land Racing Seeley G50 is another bike undergoing an engine change due to a nip-up, while the Chapman Racing MV triple that Ian Lougher was to have raced in the Senior has been withdrawn after mechanical woes.

Italian company HRT built Chapman’s machine, which is a copy of a 1974 model.