Originally Posted by
T-Mar
SLL-434 SIS is a bicycle oxymoron, as SL = shift levers and the second L = Light Action (friction version). An S immediately preceding the numbers indicates Light Action (SIS version). The correct designation for the SIS levers would have bee SL-S434. I suspect someone at Schwinn was just being sloppy, as even the hyphen is misplaced. Both the SL-S424 and SL-S434 were 6 speed SIS shifters, so there is no reason they should not work in your application.
Lo and behold, it does. At least on a stand it does. Weather, health and bicycle advocacy are all conspiring against me and I haven't been able to actually take the bike outside yet. But the shifting goes "Click-Plunk! Click-Plunk! Click-Plunk! Click-Plunk! Click-Plunk!" up and down the rear cogs on the stand. I frankly didn't expect it to work that well.