Here's a replacement alternator for a Valkyrie

[..]

http://www.sears.com/lactrical-new-lactrical-high-output-85amp-alternator-for/p-SPM11756116919

[Gideon]

Can that cost be correct?
Local dealer list a new one for more than $600.00.

[Houdini]

I bought my spare off of eBay for $129.

[hubcapsc]

Amazon has them too... the price for one on the first page
is:  $109.50 + $14.99 shipping  ...

They're not OEM, but that's doesn't make them bad.

I have a spare from a low mileage wrecked bike I got on
eBay for... I forget now... cheap...

-Mike

[Valkorado]

We slapped one of these on Big Bertha this spring.  Had a heck of a time getting it to fit until Damon cut the bolts down on back.  They were slightly longer than OEM and were hitting the frame no matter how we tried angle it on.  Caused some headaches and cussing before cutting them down.  Got mine directly from Lactrical on Amazon.  Working well so far.

[KSDragonRider]

I have put 2 of these on different bikes.  the first bike got about 10k before the bike was wrecked and scrapped, and the second one has nearly 10 on it now and doing great.

I did a little trimming on that big cast piece where the swing arm bolts in, not much just a little.  I did not do as much as Mark T did for sure, but his way would have been alot easier.

Now i need to make a cover for it.  On mine the stock cover is smaller than the alt.  I think i am going to use some polished stainless to make a cover that will look close to stock, just bigger.

I also installed a battery out of a gl1800 to be able to handle the extra amps.

[Kunkies]

Nice find Britman  , 85amps output how does that compare to stock?

[The emperor has no clothes]

I paid $129. 2 years, 30 k, no problems.

[98valk]

Nice find Britman  , 85amps output how does that compare to stock?

http://www.rattlebars.com/valkfaq/#ELECTRICS
ALTERNATOR: OUTPUT: 546 WATTS & 14.2 VOLTS @ 3500 RPM
The Valkyrie is equipped with an honest to goodness alternator located under the plastic chrome cover (which says "HONDA") on the left side below the petcock. Born of the notoriously over lighted and accessorized Gold Wing and driven by a gear directly off the crankshaft, it has an output of 546 Watts and 14.2 volts at 3500rpm. Unlike many motorcycles, once started your bike will run off the alternator alone without the battery in the circuit, but it's not a good idea to do so as the voltage drops at idle. This alternator is a strong beast (like the Valkyrie) so turning on your high wattage headlight, running lights, spotlights, custom lights, radio, CB, heated clothing and your cappuccino machine will probably do nothing more than make it proud of itself.

38 amps
http://www.supercircuits.com/resources/tools/volts-watts-amps-converter

the question is at what RPMs does that 80amps happen at. A lot of times at lower RPMs the amps can be lower than the OEM unit.
ask for an Amp curve chart to see.
most reputable alternator companies will provide if asked.

[Blackduck]

They will run with a dud battery but not recommended.
Had a battery fail away from home and had a jump start to get going, blew my head light and taillight.  Unfortunately this was at night but got home though, escorted by another bike with lights.
Cheers Steve