OK, I spoke with customer service at HD and asked them exactly what the deal is on putting a trailer hitch on the back of a bike, would it or could it void your warranty. They stated that it could due to the changing or modifying the motorcycle. Harley is actually calling it a modification and that in itself could cause you to lose your warranty.
And the sky
could fall, and the Laker's
could come back from a 2-3 deficit, and I
could hit the jackpot on the Powerball. The answer they gave you
could be useful, or not very much.
I think it all goes back to viewing each situation on it's own merits. If you pull in to your friendly dealership with 1000 pounds of trailer and gear hooked to the back end and complain about brake fade, tire wear, belt stretch, trans noise, etc., don't expect any sympathy or any warranty coverage. By the same token, if you roll in with a trailer hitch installed and complain about defective gauges or chrome peeling off the wheels or lousy paint on the fuel tank, and they try to give you the "warranty void" BS, you need to invite them to meet you in court.
Anything that isn't exactly as it was when it left the factory can be considered a modification. Changing the seat to an aftermarket product is a modification, but it doesn't void the warranty on any other part of the bike. Once again, Federal warranty law places the burden of proof on the warrantor, not on the customer. If you have a powertrain failure that is obviously due to overloading, and they can prove the failure was due to overloading and not a defect, then sorry charley but you lose. If they can't prove it wasn't a defect, they lose. And that's the way it should be. If you want to avoid having to fight for your rights in court, do yourself a favor and don't flaunt any "modifications" when you go in for warranty work (take the hitch off). Excuse me if this hurts anyone's feelings, but I don't have much sympathy for people who go to their friendly dealer for warranty coverage on a bike with an aftermarket ECM, non-stock cams and heads, high compression pistons, oversize throttle bodies, etc., and get all pizzed off because they won't cover the blown crankshaft or clutch under warranty.
Jerry