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Got a buddy where who has 2 fuel injected HDs (One's a road king and one's a Dyna low rider, I believe) Sorry I don't have the exact info.

My friend tried to swap the battery on his road king, and it fried the computer in his bike. (At least that's what the HD shop here said) THe bike went into a limp-home mode. I figured they'd be able to simply reset the computer, but they wound up selling him another one (computer). He INSISTS that all he did was take the old batt. out and put the new batt. in.

Now he wants to swap batteries on his wife's bike (The Dyna.) He wants me to do it. I'm not going to touch the damn thing, because I don't know enough about the EFI system on Harleys to know if a battery swap will fry something.

There's a good possibility that he screwed up when he replaced the battery. He's not a mechanic. He's an office worker. There's also the good possibility that the Harley Shop just screwed him over. It wouldn't be the first time the Italians have taken advantage of Americans.

Is there a special procedure for swapping batteries in an EFI Harley? This guy is actually my wife's boss - if I can help him out, that would be a good thing.

Sounds fishy, alright.

Unless your friend reversed polarity for a few seconds hooking the battery up, I can't see how replaceing the battery would fry the comp. Either that's what happened or the shop is useing it as an excuse to sell a comp with out knowing the real problem....

I'm with Buzz on this one, something just doesn't sound right. Simply changing a battery will have absolutely no effect whatsoever on the computer, EFI or anything else electronic. Shorting out the wrench from the positive terminal to the frame while tightening the battery terminal WILL, however, cause problems. Given the fact that you've mentioned he's an office worker and a moron, I'd be more inclined to think it is the operator at fault rather then the battery. As for the shop replacing the computer, it's hard to say if that was a cash grab or a legit fix. When I inadvertently hooked up my electric vest to to the wrong connector - the one the Service Manager mistakenly told me was the correct one - I got all kinds of weird stuff happening with the gauges. I took it back to the dealer, they hooked up the diagnostic laptop, cleared the trouble codes and I was on my way again (with apologies from the Service Manager after being shown the proper connector location). So in some cases the bike's computer can be reset but in others probably not, it depends upon the severity of the fault.

BTW, why is he changing batteries anyway? If they're recent models they should have the maintenance-free batteries in place and those suckers should last for years with a little bit of common sense.

sounds like he hooked the battery cables up wrong.

Gummiente wrote: BTW, why is he changing batteries anyway? If they're recent models they should have the maintenance-free batteries in place and those suckers should last for years with a little bit of common sense.

The bike's been in storage for 2 years. I really doubt he's smart enough to actually try Testing the battery before replacing it. Rich people can do that.

If the bikes in storage for two years maintenace free or not its toast. Harley batteries are designed to only go in one way, aslong as you got the right one. Some models have the same shape or size, but positive and negitive on different sides for different models. The positive is ussually too short to go to the other side but the negitive could. But how stupid are people? Im sure if you tried hard you could mess it up.
As i harley tech ive never tried to mess it up to see what happens, but i dont think you would take out the computer. If anything you might pop the 30 amp maxi fuse behind the left side cover. If it popped the bike would be total dead. nothing on or working. Its the big one in the case attacted to the fuse block. Also check the fuses in the fuse box.

Thanks guys!