Yeah, mine are original on the FD with 10k miles. No leaks. I change it often too, because its so easy. But I replaced the oil drain washers last time.
They are cheap enough it makes sense just to replace them. Worth it just to avoid having to do it all over.
So I tried one of these washers on yesterday and it fits fine. The onlybdifference between these and the triumph oem ones is the inside diameter is a little smaller but still easily fits over the plug. If anything these should work better
This is what I use on the left side needle bearings.
