Bicycle Mechanics - bar end shifter indexing problem

I have Dura Ace 8/9 speed bar end shifters on my commuter. I'm using them with a 9 speed cassette, and they've worked great for over a month, about 200 miles.

You have to dismantle the shifters to install or remove. I've removed and installed these shifters at least 3 times since I've been trying to figure out which of my old handlebars to use (I have several, doesn't everyone?). I'm always careful and haven't broken or lost anything.

Each time, they have gone together just fine - it really isn't technically difficult. There's a couple of parts that have to fit with each other just right, but there's really only one way (as far as I can tell), so if you get it assembled the only way it fits, it works.

Each time I've reassembled them, it seemed straight forward and easy - I put them together, and they work, no big deal.

Last night I installed them on yet another set of handlebars. Same assembly procedure, nothing different, nothing visible broken or no parts lost. But, when I went to check out the shifting on the rear/right shifter, the indexing was all screwed up:

call the smallest cog #9, largest #1:

9-8 index perfect
8-7 index OK, but not great, seems to need adjustment
7-6 doesn't shift

next index goes from 7 not to 6 or 5, but seems to be a "mega index" (large throw between indexes) and go all the way to or 4. It's like 2 or 3 index stops are actually missing

4-3 OK, not great
3-2 OK
2-1 OK.

I took it apart, looked at everything closely, and reassembled. No joy. I know how to adjust indexing and have always been able to adjust indexed shifters well.

What could be going on? I've switched to friction which works fine, but this has me stumped.

See this post (http://www.bikeforums.net/showthread.php?642651-Bar-end-shifters-good-or-bad&p=10786030&viewfull=1#post10786030) and read the whole thread if you must. I believe you have the same problem I had.

Double-check the position of the indexing disk, what Shimano calls the "lever boss cover" (part #2) on this pdf:
http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/SL/EV-SL-BS77-1664_v1_m56577569830628723.pdf

The fat tab should point down. The disk fits on 4 ways, so it can easily get screwed up in the reassembly process. If it's installed improperly it'll produce the symptoms you describe.

Once you've got that set right, make sure the index/friction switch is turned all the way to "index" and then really tighten the center screw. Mine loosened up even when tightened to spec. I took a T-handle screwdriver and really torqued the screw- it didn't loosen after that.

^^^Precisely.

yeah..this happened to me too. When you disassembled it, it was probably in the middle gear somewhere. When you reassembled, you were in a different gear. The click/gear thing is not properly lined up. In a nutshell, assemble and have the lever in a low gear and shift to high gear. Disassemble and reassemble with arm in low gear. Crank down to high gear. At some point, the lever and gear and tab should be all synced up at the same starting point when you reassemble.

I have the same shifters. I learned the hard way that whenever I remove them, I make sure that the chain is on the smallest cog and there is no tension on the cable.

Thanks each of you for the pointers. Yes, that's exactly what happened to me - I was careless and didn't pay attention to the derailleur position when I disassembled. Even though I consider myself reasonably experienced in bike mechanics and able to figure out a lot of simple mechanical stuff, this just had me perplexed. And then, when I went to do my last handle bar experiment, the FRONT shifter got messed up too! So, I just went back and re-read what you-all have written and pointed to above. It was pretty simple to fix, but more simple to just prevent. Sort of a big "duh." I guess, just by chance I hadn't screwed up the first 3 or 4 times I disassembled, because it really did seem like a fool-proof procedure, until the problem arose. Thanks again.