I have read the original post a couple of times, where does it say the service manager had any knowledge of this? The tech admitted he did it, and the service manager the next day ordered the new heads. It is extremely plausible that the technician was having so many problems that he pulled the swap without any knowledge by the service manager. That being said, after the fix, I would go to the general manager or dealer principle with the information and let him handle the situation.
Matt, if you read it again you'll see that the new head wasn't ordered until
after Shortdog confronted the service manager. It doesn't sound like the tech or the service manager intended to replace the head until confronted. If I'm wrong on that point, and they really did intend to replace it, why didn't they say anything to Shortdog when he picked up the bike, and why wasn't the head already ordered before he went back to talk to the service manager?
Several good points have been made, one of which is the idea that before raising too much of a stink it might be a good idea to get the repair completed properly. I've seen similar situations where a complaint to the big boss didn't result in the action expected. For instance, I've seen customers who complained too much get shown to the door, or placed on a "list" for a service appointment that never materialized, or had various other retaliatory things done. For all you know, the guy who screwed the pooch could be the son of the dealer, or some other protected person like the dealer's trophy wife's deadbeat brother. Get the bike fixed first, then worry about getting even (or not).
Jerry