Suzuki joined Honda as non-starters in the 1968 World Championships, leaving the way clear for Agostini and MV to dominate the Junior and Senior TTs, while Yamaha, through Bill Ivy and Phil Read, were untouchable in the Lightweight events.
MV signed John Hartle to partner Agostini in both the Senior and Junior races, but the week turned into a disaster for the British rider. In the Senior he crashed on the first lap at Cronk-ny-Mona, allowing Agostini to complete an untroubled victory. Brian Ball, riding his Seeley in spectacular style, was second from Barry Randle's Petty-tuned Norton.
The unfortunate Hartle did not even make the start of the Junior after a spill in the earlier Production race. Italian Renzo Pasolini, racing the four-cylinder Benelli, was expected to give Ago a hard time, but the MV rider was untouchable, establishing a new race record on his way to a start-to-finish victory, with the likable Pasolini a brave second. Bill Smith was a fine third on a Honda twin.
The feud between Yamaha teammates Read and Ivy was simmering nicely by the time they reached the Island. They were going at each other hammer and tongs in the six lap 250cc race, taking turns in the lead, when Read, ahead at the time, retired at the Bungalow on the fourth lap with a rear wheel puncture. Ivy stormed to a victory that was especially popular in view of his new lap record of 105.51mph from a standing start.
The roles were reversed in the historic three-lap 125cc race, in which both men rode the beautiful four cylinder two strokes. Ivy led Read by just four seconds at the end of the first lap, and on the second he became the first 125cc rider to lap the Mountain Course at over 100mph, a staggering effort.
However, on a fateful last lap he slowed and Read snatched the lead to win with over a minute to spare. Yamaha had wanted Read to win the race, and the cause of Ivy's problem was never discovered. It was a controversial end to Bill Ivy's TT career. He was killed the following year when he crashed the 350cc Jawa practicing for the East German Grand Prix at the Sachsenring.
The 50cc race finally bowed out with Derbi-mounted Barry Smith winning easily from the production Hondas of Chris Walpole, Les Griffiths and Dave Lock.
Hartle's first spill of the week came on the first lap of the Production race. Riding a Triumph, he crashed at Windy Corner, and Ray Pickrell, aboard a Dunstall Dominator, was able to lead throughout. Journalist Ray Knight and Trevor Burgess won the 500cc and 250cc classes respectively.
There were two Sidecar races: the 500cc World Championship event and an extra 750cc race which was ideal for British engines such as the BSA and Triumph twins.
Klaus Enders on a BMW, looked the likely winner of the championship race after setting a new lap record, but slowed towards the finish with mechanical problems, allowing his team mate Siggi Schauzu to take the chequered flag. British champion Chris Vincent was the early leader of the 750cc class, but he too was hindered by mechanical gremlins and the Kirby BSA-powered outfit of Terry Vinicombe went on to win.