Replaced my oil tank sight tube today. The first one started leaking at about 20K+ miles. The first replacement (looked same as original) made it about the same mileage (pushing 50K on the bike now). The one I just bought a couple weeks ago has clear tubing where the others were somewhat opaque. I hope this is the new/improved tubing.
FWIW, the tube had two vertical splits in it: one on each fitting where the tube is stretched over the barbs. What was interesting was that they were perfectly in line, so I'm betting it was the side next to the tank because it gets hottest there.
It was a 10 minute operation with no loss of oil. A minor price to pay for the fun of riding the bike. Heading to WV/VA tomorrow for three days of twisty goodness. Staying at the Blackwater Falls State Park with a bunch of (mostly) Triumph riders for the annual "Euro Rider Rendezvous" gathering.