Remember that amazing see-through carburetor that the Smarter Every Day YouTube channel built back in July, 2021? In that video, Destin, the engineer behind that channel, 3D printed a carburetor and shot 4K video in slow motion to show us all exactly how a carburetor works. He also brought his dad, who is extremely skilled with small engines, to break it all down for both him and his viewers.  

If you missed it (or if you just want to watch it again), no worries—here's that link so you can check it out. Today, though, we have the next logical step in your journey to understand how a four-stroke engine works. This time, YouTuber TROdesigns created a clear acrylic cylinder, then fabricated piston rings to reduce friction and keep this little block chugging away as long as possible. What’s the engine? Why, it’s an adorable little Honda XR75! 

They, too, used a 4K camera to shoot slow-mo video so we can appreciate every single thing that’s happening as the combustion chamber cycles through. If you’re the kind of person who wants or needs to put together an educational playlist to demonstrate how different parts of engines work, this video is a no-brainer to include. 

Now, unlike the SED carburetor video, there’s little to no narration to walk you through the intake, compression, combustion, and exhaust steps. So, if you’re completely new to the process, you may want to do a little additional homework to get yourself up to speed on these concepts. (Don’t worry, these videos aren’t going anywhere, and they’ll be here when you get back.) 

If you have some idea of how the four steps of four-stroke combustion work, then you’ll especially appreciate how much of this video is spent showing the process in slow motion. TROdesigns doesn’t just do it once or twice. Instead, a good chunk of this 18-minute video is spent showing how the process works over and over again.  

That repetition is good, because there’s a lot to take in. What are those piston rings doing at different points in the combustion journey? What’s that wrist pin doing? How about the valves? Even slowed down to a rate where we can begin to understand what we’re seeing, you still can’t see every single tiny motion at once. That’s why it’s cool that the video here is a bit repetitive, so you can retune your focus and see something new every time. 

As with the clear carburetor, this acrylic block isn’t going to last very long, and was built merely for demonstration purposes. Still, we’re definitely glad TROdesigns took the time to create this video and share it with us all. 

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