You need to time the engines correctly one engine with the piston at the top, and one at the bottom, and make sure the idles are at the exact same rpm. Notice how there’s only smoke coming out of one of the engines. There’s air coming out of both because of compression, not because their both running

nobody gonna mention that cokenail😆

Now do that until you have an inline 8 cylinder two-stroke engine, and put it in the kart.

Right engine is not running but still shows the paper moving because of compression escaping through the exhaust and I say this because there was zero smoke coming from the right engine.

the first engine must be in TDC second engine must be in Bottom Dead Center, engines must be synchronized, when first make the power stroke the second must make the compression stroke.

The fact that this lad just has a pile of 2 strokes lying around makes me sooo jealous. Keep up the great work!

I had a motorcycle that was made almost exactly like that back in the mid 1970's. It was a 500cc Yankee. The engine was made with two 250 cc Ossa barrels mated on a common crank shaft. When the folks at Yankee were initially considering the splice, they tried the engine with the pistons firing on opposite strokes so that power was continuous but found that the bike (which was intended for enduros) had a more useful power band with them mated on the same stroke. The power was like that of a 500cc single. They called it a twingle, or at least the riders did. It was massive in the woods. If you had the alternate stroke config. it just spun the tire and the power didn't get to the ground. Wish that I never had let it go.

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Reminds me of Garage 54 putting two 4 cylinder engines together, and running them in a Lada(?).

“For the toughest of weeds”

Even though this is a twin engine setup and not twin cylinder, its still very cool and man it sounds way cooler then i would have expected. Nicely done.

It's pretty cool how you connected the two engines! I wouldn't have thought to do it that way!

I have been looking for something like this for ages!!!

Interesting build, and very informative. Two things that stand out. A carburettor balancer is required otherwise idle will never be stable or you can accidentally run one lean at operating revs, ruining that cylinder. Secondly, cooling is now missing on the number two engine as the fan shroud was removed and no metalwork to guide the airflow from the front engine, or the machined impeller to even slightly reduce cylinder head temperatures. I guess it is a work in progress. Perhaps fitting a multi blade shrouded propeller on the drive shaft, with adequate baffling ,would be able to draw the air past the cylinder and vent it away from the engine.

those two motors have a beautiful sound when working together congratulations great idea

Pretty cool. I think the cylinder without the pull start would be in danger of overheating if you did any real work with it though. And like others said, putting the two cylinders 180 degrees out would prevent the assembly from rattling apart.

Hands down the coolest thing i've ever seen anyone do with a couple 2 stroke engines.

Very ingenious! Creative crankshaft coupling is an interesting challenge to watch other people solve!

Very inventive work. Would be nice to have that lathe. Twin 2 strokes sound so mean. Two Walbro carbs and steel tuned pipes is the ticket. Nice work on this one!!

Now you have two engines that will be a pain in the ass to start each spring 😁👌