old's'cool

So, I got this NOS set of subject SIS shift levers off Ebay, that exactly match the Velobase description, appearance-wise.
I figured something was odd already when I mounted them, and tested the RD lever before hooking it up; it had only 4 noticable detents. I went ahead and hooked it up, with Shimano compatible cable & housing, BTW. Rear cluster is a 6-spd Uniglide, and RD is mid-80s SIS compatible Shimano 600. I found that, whether in SIS mode or friction mode, that the maximum range I could get was 4 out of 6 cogs. As a check, I changed the RD to a SIS compatible Exage, with the same result.
So, as the next step, I changed the lever to a downtube 6-sp Exage lever I had in my spare parts bin. This lever can shift the full 6 cog range, in friction or index; however, I have not been able to adjust it to index well over the whole range.
The question, and the point of this thread is, what is up with the SL-BS50 lever that I have? Next question is, how difficult would it be to take the guts out of the Exage shift lever, and put them in the bar-con, and would that be the entire solution, or the pull radius of the bar-con shifter going to hang me up? Based on my research prior to purchasing, the SL-BS50 is supposed to pull 6 or 7 speeds, so I'm very puzzled as to why the lever I have cannot pull even 5.

ham

Try disassembling it and putting it back together in different configurations. I'm almost certain that one of the positions will give you the proper travel.

gaucho777 

I don't have experience with these shifters but I wonder if something is out of whack inside. Bent spring, cracked plate, or maybe part of the assembly is oriented 90 degrees off. If no other explanations are suggested, I'd disassemble the levers and check the orientation of the mounting plate if possible and inspect all the pieces while it's open. (Edit: +1 to ham. I think maybe that's what he reply meant by "configuration"--i.e. orientation of the mounting plate.)

Jeff Wills

This is symptomatic of the indexing disk being in the wrong position. Take a look at the part called "lever boss cover" for any of the Shimano bar-end shifters on this page: SHIMANO Dealer's Manual / User's Manual . (Any of the SL-BSxx shifters will do.) Note that the fat tab points down when in the correct position. However, the lever will allow it to be assembled with the tab pointing in four different directions! Take the lever apart, orient the disk correctly, reassemble, and it should work fine.

(Dammit, the Shimano website no longer allows direct links to their PDFs.)

Note: the center screw on the shift lever should be very tight or the shifter will tend to creep to a point halfway between "SIS" and "friction". This can damage the shifter.

Here's what I'm talking about, from a non-Shimano image:

old's'cool

Thank-you my friend. That was spot on. I followed your advice and information, and my shifter is now working beautifully in index-mode. I love this forum!

For future reference of those encountering similar issues; while I had the indexing disk in the correct orientation, my initial downfall was that the shifter was not in the lowest position. I found that to make sure it it is there, set the lever to the friction position, and then move it to the lowest position. Then you can switch to index, and you should be good to go.