Eyedrop

Hello! I have a bike with zipp vuka aerobars and dura ace 7800. I noticed the shifter mount on the right side bar end was very loose. So I used a flat head screw driver to disassemble the shift lever, then tightened the mount with a hex key by turning counter clockwise. I reassembled the lever exactly how the sl-bs78 manual said. Now I can only select the two smallest rear gears and the lever won't move upwards to select an easier gear. The shimano tech doc didn't mention anything about the cable during installation. Can somebody please help me? Thank you guys!!

Andrew R Stewart 

There is a square shaped fitting that the lever sits on. This piece will engage the lever's "base" in only one rotational manor. If this square piece is not mounted in the lever's housing properly the lever will be off rotationally. IIRC this piece has one wide/thick edge which needs to be pointing down for the lever to work properly. But I just fiddle with it's placement until the lever travels through the entire range. Andy.

FBinNY 

Without looking up the docs on your levers, I suspect that you might have the internal assembly on your lever turned 90 or 180 degrees where you attached it to the boss on the barcon body. Click the lever to either end of the range and remount so it's oriented correctly based on which end of the range it's parked in. In the future, shift to high before removing the lever, so you know to remount with the lever pointing down.

If you remount correctly as it was before you took it apart, all the adjustments should be petty close, but keep in mind that if you move the entire unit in ot out from the end of the bar, that can lengthen or shorten the cable run throwing all the adjustments off. If slack cable is the issue, odd are that it was installed, not bottomed against the bar, and you moved it to the correct position, but now have to take up cable slack at the RD either with the barrel adjuster or at the pinch bolt.

Eyedrop

I've tried assembling it with the square shape on the inside of the fitting both on top and bottom (manual says bottom). I'm in the smallest gear in the back. I've also rotated the outer fitting both ways. No matter how it's assebled, only 2 gears can be selected. I have a feeling I'm going to have to loosen the RD cable to give me some slack so I can try installing it while the lever is in the easiest gear. I just don't understand why this isn't working. It seems simple enough

Eyedrop

There is even a little arrow on the outer shifter assembly that I have pointing downwards. Neither upwards of downwards works. I've also experimented with each positio. Of the inner housing, trying all combinations.

Andrew R Stewart 

In addition to the square "base" needing proper orientation the lever must also be properly orientated WRT it's indexing position. Lack to get both aspects correctly arranged at the same time results in your description. Andy.

Jeff Wills

You're missing the point. The part that you need to look at is called the "lever boss cover", part #2 in this PDF:
https://bike.shimano.com/media/techdo...9830728256.pdf
It's got a "fat" tab that needs to be pointed down before you assemble the shifter on the body. If it's not oriented correctly, the shifter will have exactly the symptoms you describe.