Compatible Alternator?

My bike has a 74 crank in it with the correct dyno and cover to work with the 78 wiring. I want to step up to the newer style dyno cover which has a different bolt pattern for the alternator. Which rotor do I need to make this happen?

This is the cover I'm wanting to use.




Les

I know the 79 1000 ltd uses the older left over 78 crankshaft in them with the newer style cover,not the big pin crank like the mkII till 1980.
Maybe check around to see if somebody has a picture of the parts from a 79 to see if they would work.

I cant quite tell from the picture but i do know if the coil windings are on the outside you gotta stay with that. Because when i was talking with john about my motor, he told me that crank ends are diffrent compared to the one with the coils windings on the inside of the rotor (mk11). John told me he could make them work but you would have to switch a diffrent end on the crank.I guess the holes are diffrent size. Hope that helps.

According to the old babbits site the 78a2 takes stator 21Q76-023 and the 79b3 takes 21076-023.
From what I can see in the pictures it looks physically the same to me anyway,Im guessing if anything the 79 might have a little more output

Here's the difference inside.
newer style

older style


Les

The top one is what is on my 80 1000. The bottom pic is what my crank had on it. That is a nice cover wish mine looked that good.

Looks close to me anyway,in 80 the ltd got converted to differant charging system like the mkII
Top picture is the 78,bottem is 79ltd

Dont know if its true or not but when i ordered my new performance stator from elctrosport which was a big hassle, I ended up with one from a kz 750.They told me thats what charging system i had . I dunno. I had to cut off the oil plug on the wires and install a 1000 plug on but it worked other than that.

I need to change the rotor also so I should have asked what rotor is compatible with my crank that will work with the new cover.
Powerstroke, That cover is a brand new O.E. I found, also got the points cover too. Nice looking parts.

Les

Ya thats a sweet cover. Man, if you decide you wanna part with it let me know.I hope it works out for you, i just remember what john told me.b/c you know iam building the other motor and i was wanting to just switch all my other stuff over to new motor. Once he seen it wasnt a mk11 crank in it, he told me about it. That was aother reason why i just had him weld up a mk11 crank. i know you need the 80 ltd mk11 style rotor and stator. I can send you pictures of my old stator and dimensions if it will help any.

I remember speaking with John on the same topic when he done my Mk11 crank for the turbo, Just can't remember which year rotor will work on the small pin cranks, I know there is one and I don't want to buy more than the 1 I need.
I'm keeping the cover, I'd like to find a couple more to put back, they're fetching big money now on ebay.

Les

Let me know if you want the dimensions on the stator.