Shimano SIS index shifting, no click

[woohooblair]

I recently acquitred a 1988 Miyata 615 that has the shifter you can select to be either friction or SIS. I have been using the SIS. The sifter on the left has quit "clicking" into place. It still changes the gears, but as if that side is now friction only. It does click into the spot for the first crank, but not the other 2. I have spratyed it good with WD40 and worked the lever hoping it was just gunked up. I took the screw out of either side and sprayed in there and it didn't help either.
Suggestions of what to do next?

[DaveM]

Some shifters have a little lever on the side that switches between friction and index (SIS). Make sure that is all the way to the index setting.<br />
Are you sure the left lever ever had indexing? Early SIS shifting often had friction on the left (front) and only indexing on the right (rear).<br />
BTW, WD40 will break up grime, but it is not a lubricant. You should try to get some chain lube or grease into the shifter. The WD40 would have dissolved any lubrication that was in there.