Well, this was a tough one! This rare bike is a Haythorn 4, the creation of a J Haythorn out of Scotland. There is very little information out there about this bike, but what there is shows that Mr. Haythorn was mechanically gifted.

I was just at a museum in the UK, and I encountered this fascinating motor. Can you tell me what bike it belongs to?

I just watched a movie (I won’t say which one it was because then you could look up the bike) and the opening scene involves a motorcycle. Can you guess which one it is?

We’re going international for this one! My buddy Dennis from Beach Moto is currently in Europe enjoying the Isle of Man TT, having also enjoyed the Mugello GP a week ago. He just sent me a picture of an interesting motorcycle he saw and I want to see who can identify it first! I’ve (poorly) photoshopped out some obvious details, …

Here’s a frame. What bike does it belong to?

Congratulations to Facebook commenter Bill Beebe, who was the first person to correctly guess that this was a Moto Rumi!

I stopped by Robb Talbott’s museum on my way up to the Quail, and I couldn’t stop staring at this pair of exhausts. Who knows what bike they are from?

It’s been a while since we’ve played this game, so guess this bike!

David N found this seat, but he (and I) don’t know what it’s from. I’ve been very impressed with y’all when it comes to your knowledge of bikes…so does anyone know what motorcycle this belongs to?

Congratulations to David N, who made quick work of this episode of Guess That Bike by identifying this Motobi Spring Lasting. You guys are good at this! Tomorrow you’ll get a “Guess That Bike” submitted by David where neither him nor I know the answer…

Reader Mark J recently shared a set of photos with me from his time at a former museum of small Italian bikes. You’ll get to see all the cool logos once someone is able to guess this one…

David N. was at the VJMC show in Eustis this weekend – he’ll be sharing his thoughts soon but he kindly sent over a stumper of a picture for Guess That Bike. I’d kindly ask anyone who was at this show to recuse themselves from the guessing. Everyone else: what’s this bike?

Congratulations to Gregor H, who was the first to identify that this was the tail of a 1968 Indian Super Scout!

Congratulations to Facebook commenter Craig C, who was the first to identify that this ‘not a BMW’ was in fact a Ratier. Bonus points because he even found the article that I snagged the photo from.