For the people that are not aware of what GRC is quoting it's called the MAGNUSON-MOSS WARRANTY ACT of 1975
This just states exactly what GRC was saying, it's a crap shoot, the burden of proof does lay on the Manufacturer to prove the modification caused the malfunction. But if you don't want to go there take the modification OFF!!!
And he makes another good point DO NOT go into your local dealer and brag about your modifications, you may be in good standing with them now, but that can change as quick as the weather. It is sad that they can pick and choose what they want but even the changing of a HD stock headlight to there own HID headlight is a modification and if you are having problems with your charging system, well there you go. All this stuff that they sell in the parts dept that is refered to as accessories or performance parts are nothing more than modifications and they give HD an out in warranty claims.
T'is too true. Everything we do is both our enjoyment and improvement of the bikes and an excuse for the lazy, parsimonious-cheap-assed, unfair, unwilling unscrupulous or just plain dumb dealers that are sometimes (ok, too often) out there to avoid a responsibility.
Hearing of warranty claims denied for work done to a bike that are obviously not the cause of the failure is all too common. It must make sense somehow, somewhere to someone. But denied service and responsibility doesn't make sense to me.
The dealer makes its money off the customer after all. It doesn't even lose money on warranty work. It may not make as much. But unless it's just stupid and takes far longer to do a repair than it should it's not going in the red.
So either Mother Harley has the fear of Willie scared in to these service departments on the issue of warranty claims handling or they expect to be so poor at their job they can't do them quickly enough to at least break even. Guess they could be just lazy and wish to avoid any effort they can. But that makes even less sense....
It's all a waste. It is a real part of the explanation of why they continue to sell fewer and fewer bikes though. Young riders used to other nameplates aren't used to and won't accept it (even if they were interested in the "look" of a Harley). And those of us that do stay with the bikes do so only so long. At least some of us do get less and less patient as years pass.
I know two guys that have stopped owning bikes because they didn't really want anything other than an HD but wouldn't suffer the dealership any longer. Others are like me that keep the bikes but do everything themselves and try to avoid spending money to support the MoCo as much as they can. It does suck far too often for far too many.