Michael Dunlop has yet to complete a lap on the Team Classic Suzuki at the Classic TT after retiring for the third night in succession.
The 28-year-old has won the Motorsport Merchandise Superbike race three times in all since his maiden success in 2013 and is bidding for his third consecutive victory on Bank Holiday Monday.
However, the 15-time Isle of Man TT winner has been beset by issues this week while key rival Bruce Anstey has been in the ascendancy.
The Kiwi clocked the fastest lap of the week so far last night at 125.486mph on the Padgetts Yamaha YZR500 and was also quickest on Tuesday and Wednesday.
Dunlop, who will also compete in the Bennetts Senior and Dunlop Lightweight races on the Black Eagle MV Agusta and Turner Racing Yamaha machines respectively, admitted he is facing an uphill battle with the big Suzuki.
“We’ve done no laps at all and the boys have been working hard and putting the effort in, so fair play to them,” he said.
“But we just need to get laps done and get going, so we have issues.
“I had a wee lap or two on the 250 and that’s about the long and short of it.”
Anstey had no such problems as he continued to set the pace on the YZR500 GP machine, opening with a speed of 124.881mph before increasing the pace to 125.486mph on his second lap.
“It’s the best the 500 has ever been out there,” said Anstey, who won the race in 2014.
“Clive has done a fantastic job over the winter. The second lap would have been even better but we caught some slower riders and I took it steady getting past them. I’m ready to race now.”
Horst Saiger was second fastest at 123.828mph on the Greenall Kawasaki followed by Dean Harrison (Silicone Kawasaki), who lapped at 123.739mph.
Manxman Dan Sayle topped the Lightweight times on his Yamaha TZ250 with a speed of 115.549mph, but Anstey’s unofficial lap record from Wednesday remains the benchmark at 118.812mph.
Jamie Coward (108.669mph) and Josh Brookes on the Winfield Paton (107.781mph) were the top two in the Senior class, with William Dunlop (Davies Motorsport Honda) third fastest at 105.935mph.
Michael Dunlop (Black Eagle MV Agusta) retired at Quarterbridge.
Michael Rutter led the times in the Junior session with a speed of 102.063mph on the Ripley Land Racing Honda.
Meanwhile, Ballymoney’s Darryl Tweed set the pace in the Manx Grand Prix Newcomers A session at 115.092mph.
Practice was flagged off early at 7.40pm due to deteriorating visibility between Bungalow and Windy Corner.
Chris Barrett was reported to have come off at the Gooseneck in the Lightweight session and was taken by Airmed to Nobles Hospital with a leg injury.