Grip-shift brand of shifters? Don't have to be replaced in pairs. Check recycled cycles. They're likely to have a replacement right-hand one. Or they might even have suggestions about just swapping out the detent mechanism, because in a GS it's just a spring, a ball bearing, and a carefully shaped series of dents in a bit of material, and what you're facing is either a broken spring or more likely a worn out series of dents, and those are typically both replaceable. ziptie might have some suggestions about this, as well; he has done some GS work and found parts in Seattle.
no subject
Don't have to be replaced in pairs.
Check recycled cycles. They're likely to have a replacement right-hand one. Or they might even have suggestions about just swapping out the detent mechanism, because in a GS it's just a spring, a ball bearing, and a carefully shaped series of dents in a bit of material, and what you're facing is either a broken spring or more likely a worn out series of dents, and those are typically both replaceable.