Hi,
First let me introduce myself. Peter de Vries from the Netherlands. I have a technical issue with my SRAM derailleur.

I have a nearly new derailleur (done only a few hundred kilometers), SRAM X9. It won’t shift to the smallest cog.
I’ve removed the cable to be sure that a tight cable wouldn’t be the issue. Now the derailleur just doesn’t go to its most outer position. I have to help it to get there. As seen in the video: A

h no, I can’t post an url with less than ten posts on my name. Please copy-pasts “watch?v=aqLYsGZILkA” after the normal youtube url.

Without the chain it does go to the most outer position.
What’s the issue? Could it have to to with the fact that the chain on my bike (recumbent) is three times as long as the chain on a normal bike?

You might be able to solve this by screwing the b-tension screw in a bit. Top pulley looks a little high and forward.

When you're in big chainring/big cog gear, does the derailleur still have plenty of room to move forward? If so, removing a chain link might help keep the derailleur from getting hung up on itself.

​Video for everyone:

Also might be a little gunk in the derailleur, have you tried spaying it down with some cleaner? WD40? PB blaster?

If suggested actions above don't help.......................I had a similar issue a few years ago when I replaced an older X5 RD with a newer X7 on one of my steel RANS recumbents. (Both RDs with long cages.) Would no longer shift to the little cog. Found some info online suggesting that SRAM had changed the thickness of newer X7 RD mounting tabs - making it thinner to compensate for thicker derailleur hanger tabs on current mountain and other bikes commonly using the X7, most of which had derailleur hangers that were aluminum and thicker than in the past. At any rate, a suggested fix for bikes with less-thick hanger tabs (like on my steel frame) was to put a washer on the RD mounting bolt when fastening to the derailleur hanger to move the RD out just a bit. Which I did and which fixed the problem. Washer is a bit thicker than 1.5mm. Shifting to both hi and lo cogs fine since doing that. Cheap fix could be worth a try.

Thank you for posting the video. I've tried with the b-tension screw and can't notice any difference between the settings.

Yes I forgot to mention, it is completely clean and oiled.

Thanks! I've put a washer between the frame and the derailleur and it helps a bit. I think it would help if i could even move it further away but I don't dare to try a thicker washer because the bolt of the derailleur won't go in the frame far enough and I don't want to damage the thread in the frame.