The stock rubber bits make it pretty easy with no stretching. It's been a while since doing one, so don't recall how to do it, but your knowing it's possible should make it easy for you to figure out the solution. Essentially, one side will go in farther than the tubing, giving enough space on the other side to slip it on. Try it without the grommets first to get the idea.
If you do it like Blaine (with the shorter nonS stalks) - remove the black plastic do-nuts from the turn signals. The signals will then mount normally.
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