I never bought a Harley extended warranty. Usually, dealer warranties are grossly overpriced. I have had a few friends who either had a tough time getting the dealer to honor the warranty or who were simply told that the warranty did not cover whatever went wrong with the bike.
I'd like to read the warranty document to see what it covers. Just signing up for a warranty does not mean that it will cover what you think that it covers.
Most twin-scam motors can go 40k or 50k without any serious problems, though some fail much earlier. If you replace the automatic primary chain adjuster with a Baker unit, you can probably expect to get around 60k before you have to start tearing into the motor. If you replace the cam chain tensioners at 25k to 30k you can greatly reduce the odds of a chunk of hardened plastic clogging up a journal on the cam plate or causing other lubrication issues.
If you are a low-mileage rider, then you are probably just as well off putting the warranty money in the bank and using it to make repairs or to perform preventative maintenance on the motor.
The twin-scam motor has some flaws that are worthy of its own Shakespearean tragedy. However, if you can find a shop where the mechanics are aware of these issues and get ahead of them, they can prevent a lot of issues for not too much money.
Leo and AJ from Open Road Cycles in Denver, NC have pretty much figured out what you need to do to keep your twin-scam motor running. One of the least expensive mods is the Baker manual primary chain adjuster. You can pay them now, or you can pay them a lot more later.
Pete
The total repairs on my 2009 Dyna Super Glide with a little over 61k on it were around $800 to replace the inner primary and clutch bearings, with a new clutch and a Baker manual primary chain adjuster. I just spent another $800 on a new oil pump, cam plate and cam chain adjusters. That is less than what a warrant would cost and I'm not at all certain that a Harley extended warranty would cover those repairs.