A Fine Mess (1986) on Netflix

While filming on location at a race track, womanizing bit actor Spencer Holden, who lives life on one scam after another, overhears a couple of inept thugs named Binky and Turnip while they dope a race horse with a supposed undetectable super stimulant. The thugs find out that Spence overheard them and will do anything to catch him so that he won't go to the authorities with the information. Spence, however, enlists the help of his best friend, drive-in carhop and aspiring restaurateur Dennis Powell, to bet on the race with that horse so that they can make some guaranteed money. Spence and Dennis end up not only having to outrun the thugs, who manage to put a few bullet holes in Spence's car, but also the police after they find Spence's bullet riddled car and after the race horse, Sorry Sue, ends up dying from the drugs. Throw into the mix an antique player piano of which Dennis comes into possession, sympathetic but naive auction house employee Ellen Frankenthaler who is attracted to Dennis, and exotically beautiful Claudia Pazzo who is interested in buying the piano and who Spence can't resist, and Spence and Dennis may be in more trouble than they could have imagined.