headasunder

My 10 speed 105 right hand shifter is playing up on the down shift, I plan to change the cable + outer this week but know it needs more than this as it is not always clicking on the down-shift. So I will pull back the hood and flush it out then lube. Question...what products should I use, I was planning to flush it with wd-40 and haven't decided on a lube yet my experience with an old shifter tells me they don’t like anything to heavy and gummy in there. Suggestions.......

Retro Grouch 

It doesn't take much. Honestly, I just blow out the WD-40 with an air hose and rely on the residual lubricating properties. It's worked for me.

dsbrantjr

I have found that LPS-1 spray works well, it is fairly light and does not seem to gum up significantly. They have heavier LPS-2 and -3 as well. I have used Pro LInk Gold chain lube also seems to work fine.

Looigi

Yeah. IMO, this may be one of the few really good uses for WD40 on a bike. It's mainly solvent (basically OMS) with a light lube. The solvent helps loosen up the existing lube which is also thinned by the residual light lube.

I've used LPS 1, 2 and 3, and of those LPS 1 would be OK as it's a very light lube.

Pro-Link is lube and solvent in paradichlorobenzene (same as mothballs). This causes it to set up semi solid, which might not be the best for shifters.

Andrew R Stewart 

After flushing out shifters with a true solvent (I like Clean Streak) I'll blow in first TriFlow then a thicker lube second. I use an air hose to insure the lube has gotten into all the surfaces. Andy.

dksix

I think PB Blaster works better than WD-40 for cleaning. I've used both for cleaning air valves that have build up from in line lube systems and the PB Blaster always seems to leave them working a little smoother than when I've used WD-40.