I'm replacing the gear-shift cable on a three-speed ladies' bike, the hub is not a sturmey archer. I'm not sure what kind it is, but the Shimano attachments the folks at the bike shop gave me fit nicely. The shifting mechanism itself is a handle-bar shifter (you know, where you turn the bike's handle instead of flipping a switch).
I see how it's all supposed to fit together, but i can't seem to get it to work. I can't get the cable tight enough, and i am not sure if i have the handle-bar part right.
Any tips?
Anyone know where i can find instructions? A repair manual would be great, but i can't think where to find one for this model. All the tips i've found on the web are either for 10-speeds or Sturmey Archers- and they don't help. Any advice would be most helpful. Thanks!
Oh- and the bike is a late 60's- early 70's JC Penny Lightweight ladies' 3-speed. Thanks!

Lemme get this straight: the bike has grip-shifters? On a 3 speed? I haven't seen them, but that doesn't mean they don't exist. Are you sure that the shifter is meant to work with that model of 3 speed hub?

Where are you having trouble tightening the cable? Normally the way to tighten it is to put the shifter in the position where the cable has the most slack possible. Then pull the end of the cable as tightly as possible and tighten down the attachment point on the hub.

Well, everything on it is original except the cable itself. I was test-riding it and it snapped. Oopsie. Sooo, if by "grip shifter" you mean the kind where the handle-bar grip doubles as the shifter, yes. It is a grip-shifter on a 3-speed. They can't be that rare, the bike is from JC Penny's.
What i'm having trouble with is keeping the cable taut while tightening down the attachment point. If i'm keeping the gear set in "neutral" on the hub with one hand and holding the cable taut with the other, how do i tighten the attachment point? Even if both hands weren't occupied, i'm not sure i have the arm strength to keep the cable taut enough. So, mostly i was wondering if anyone had any suggestions as to how to keep the cable nice and taut while tightening the attchment point.

Try putting it in low when you tighten it. Also, is there a fitting in the cable line that has threads? On some brakes and gear shift mechanisms, there will be something you can twist to increase or decrease the tension. If there is one of these on yours, adjust it so that it makes the cable run as short as possible. If you need more tension, you can twist it to make the line a little longer.

Twisting it to make the tension greater would be done AFTER you attach the cable.