You're going to sue (and win) them for....what? You can't sue (and win) somebody to put a website up. That would be slave labor; on a ruling like that, I could sue you to wash my kitchen.
As far as parts/service/support, legally they are still offering it. You're just angry because it's not convenient for you. You can't sue (and win) for inconvenience.
But let's say you decide to go forward with this. You're entering the realm of contract law, specifically a breach of contract in regards to a warranty. Exactly what part of the warranty contract are they not meeting?
Look, HD had a team of lawyers review all outstanding obligations in regards to product support and what has been promised to the customer. They didn't willy-nilly start closing down sites and closing a multi-million dollar motorcycle brand if there was even a remote risk of someone coming back at them. At best, you can report them to the Better Business Bureau in your state, and that's it.
You can always sue, you just won't win. If you think that by filing a suit, they'll agree to settle because it'll cost them more money in legal fees than what you're asking, you're wrong. They probably have salaried lawyers on staff, so it won't cost them a dime to drag you through court. And in the extreme case where you win, you'd only be awarded what's called "nominal" damages.
The whole process will be like masturbation without the payout.