It's funny that I'm in the salvage business and never really paid attention to frame weight until I ship one
I recorded your info and will start keeping track of others.
On the tank weight I'm not surprised.
Back in the late 70's all the manufactures were going to Aluminum Swingarms.
I wanted a aluminum swingarm for my 79 RM250 because I thought it was lighter.
The reality is, most of the aluminum swingarms weighed more then the steel ones
Similarly....
2017 KX450F 240lb curb weight
1997 kx500 233.7lb curb weight
Instead of throwing money away making titanium tanks the manufactures would be way better off using titanium fasteners.
You would probably shave 5 lbs or more off the bike and it would be cheap as most of the fasteners are readily available.
Oh, but that isn't as flashy as a titanium tank.
The more we struggle against the morass of corporate blather the more we get sucked down