Three riders were injured in an accident at the Black Dub, on the Glen Helen section of the TT course, during the first lap of Friday evening's practice session.
Michael Weynand came off his Kawasaki, the petrol tank of which became detached from the machine, caught fire and ignited a hedge.
The bike was then struck by the machines of Jim Hodson and Victor Gilmore, who received rib and shoulder injuries respectively.
The fire brigade was called to put out the flames, and the session was red flagged at Ballacraine.
It took a long time to clean up the debris and sweep the road, but most of the riders managed one more lap after the session resumed.
Fastest in both the Superbikes and Superstocks was Ian Hutchinson, at 127.049 and 125.570 miles an hour.
John McGuinness was quickest in the Supersport Junior, lapping at 122.423.
(Picture: Ian Hutchinson at Ballaugh Bridge).