Yamaha 750 Twin

I just finished building the engine for the new 750 twin.

It's a Yamaha XS650 bored to 750cc. The crankshaft is re-phased to 277 degrees, and has new Falicon connecting rods. The new firing order is closer to the modern twins so it's smoother and makes a little more power. New JE pistons were fitted at approximately 11.5/1 compression. The head has been re-worked for proper flow, and it has a pair of Mikuni VM 34 round slide carbs bored to 35mm to provide the A/F mix. The cam is from WebCam racing and is one piece hard welded and ground for the 277 re-phase. This is not a cut and rotated camshaft. I'm using a Power Dynamo ignition which is a digital magneto/generator unit that needs no battery even when running lights. It has several switch selectable ignition curves, with one having a rev limiter. The initial test run was done with a set of TT pipes, but a 2 into 1 exhaust will be used on the bike.

Check out our Facebook page for a video of the first run!