Is this the right R/R for a '77 750B2

One from Amazon

One from some site on the internet

Contact these folks; they will have what you need. Great products and great prices. I have one of their rectifiers on my bike and it works perfectly. Ed

www.oregonmotorcycleparts.com/Products.html

#1 No
#2 Yes

Thanks for the help guys.

As Steel said,
#1 is incorrect. Looks like it would work on a 78 or 79.
#2 looks right, but the description is wrong. The type of regulator on the 76-77 750 twins does not "dissipate extra voltage". The only thing to watch out for on regulators like #2, is sometimes they get the field polarity wrong and the regulator won't do anything, and thus you get no power from the alternator. There is an easy work-around for that, though.

Oregonmotorcycleparts.com is aware of the poarity issue and makes them correctly. Plus I think he still has a very good warranty going. Last I checked, he would only have a separate regulator and rectifier for your bike.

I don't mind two and would rather get the right thing.