Portland, Ore., September 10.—Angered at alleged mistreatment, Arthur Pelky, world’s heavyweight title claimant, yesterday canceled his contract with Tommy Burns as manager.Immediately after canceling his contract with Burns, Pelky today gave to a Portland sporting editor a signed “confession” in which he alleged that he and Burns faked their six round fight at Calgary on March 26, last. Pelkey charges that Bum9 took advantage of the fact that he was penniless and induced him to frame up the match, and that they rehearsed the battle nightly in a garret.