Malossi MHR Big Bore cylinder with 50mm bore is one of the fastest cylinders you can mount alongside the 2Fast model. 77cc with approx. 25bhp to be expected with relevant tuning measures. 7 overflow ports. Cases must be worked to allow the crank stump to fit into the cases (to approx. 57mm) Wide range of base gaskets allows for easy adjustment of the compression ratio. All necessary parts supplied.