WOW! I once had an identical, ideal chain throw. It was on a mid- 80's Yamaha SR250, just like
THIS ONE except mine was ugly and had a big milk crate strapped down to a handy luggage rack. Anyway, when I found the chain I didn't find the master link. I was a bike mechanic at the time, so only a 1/2 stupid kid. Either the master failed (it was an older chain with a "clip-style" master), or I failed to get it clipped correctly. It is possible to get that master mostly clipped so that at a glance it looks clipped, but not actually get the clip locked into place. Very dangerous.
I was going down the interstate at the bike's top speed of about 69-71mph, surrounded by 18-wheelers, when the engine suddenly revved up and I suddenly began an "unpremeditated deceleration." LOL! I did not have any damage to the bike, so apparently the chain magically flung off the back of the rear sprocket. I did look back fast enough a the right moment to see the chain fly through the air, hitting the ground right in front of an 18-wheeler that was suddenly dramatically bearing down on me....
I still thank God that nothing locked up when my chain was thrown. I am confident that I would not be here today to tell you about it.
The humble chain is a very serious thing.
What an adventure!
Mut, I am glad you and your bike both seem to be OK.
As a side note, I later sold this same SR250 to a dear friend to be his first bike. Soon after buying the bike he was driving down the interstate at about 55mph near his house and had a couch fall out of the back a pickup right in front of him. It all happened instantly, and the couch hit the ground immediately in front of my friend. The bike stopped, but he didn't. He was flung over the bars and tumbled to a stop, banged and bruised, but mostly OK. Traffic eventually slowed down, and my friend pushed the bike to the side of the road, and I think he even drove it home (even the the forks were somewhat pretzeled). It was a hit and run situation, but there were no medical bills involved, just total loss of the little bike.
Peace and grease,
-steve