Originally Posted by fishguts
I'll be building one as soon as engine #2 arrives. I'm pairing up two 25cc weedeaters, connecting them with plates at about a 60 degree V with a common drive. The intakes will be connected and it will run off a single 50cc carb. I'll post photos so if anyone wants to copy the procedure they can follow along. There are a couple challenges but I don't think they're insurmountable.
Here's a "before" picture with the two motors mocked up together. They are essentially identical but were used in different configurations so the engine cases are not exactly the same. It would have been easier if they were, but I'll work with that I have. The next step will be to make patterns for the connecting plates.
You can see I have them set up so their flywheels are on opposite sides. This puts the intake ports in the middle and will allow for a common manifold and single carb. This also means that their rotations are opposite, the right hand (forward) motor in the picture being the one with rotation the same as the driveline needs to be. So ... the left hand (rear) motor will need a two-gear setup that will turn a shaft in the proper direction below the cases and connect on the drive side. This means the connecting plates will have a place for mounting bearings and the shaft.