On the test bench, Malossi 270ccm, V4 cylinder head @ 63mm stroke

As a guest on our test bench, our employee Manuel with his Derbi GP1 125 @ 280ccm and a very powerful engine concept.

Even if the unobtrusive appearance of the GP1 brings tears to your eyes, the very powerful engine immediately puts a smile on the driver's face.
When the engine set up on this project began, Malossi probably only just got one Cylinders for the 300 engines thought about.

Therefore one serves here KB-Racing crankshaft with 63mm stroke from the 300 motors as the basis for one 270cc Malossi cylinder, which was actually intended for the smaller 250 engines.

So that the crankshaft and the piston can enter into a connection, the piston from the Malossi kit had to be provided with a 16mm piston pin bore.

The 270 cylinder from Malossi comes from the factory with a rather, well, cautious squeeze dimension.

Therefore, the cylinder only had to be underlaid with a 3mm thick base seal despite the 0,8mm stroke extension.

With the 4-stroke, most of it is a matter of the head, in the truest sense of the word.
What is with the well-known 2-stroke channel areas and control angle, is with the 4-stroke valve area and camshaft lift.

Especially the 250 and 300 engines from the Piaggio range suffer, in terms of performance, from the very throttled cylinder head that the Piaggio modular system uses from 125 to 300ccm.

Just replacing the factory throttle with the Malossi V4 head would already help many a GTS250 / 300 to run more smoothly and to get plenty of torque.

You can tighten the 300ccm dish even further with a Malossi camshaft.

For comparison,

a Vespa GTS300 is specified by Piaggio with 22PS - on the crankshaft.
After all horses have run through the drive and gearbox, an average of 19 of them arrive at the rear wheel.

Our test bench diagram also shows the rear wheel performance of Manuel's GP1 ...

A very good result for the first litter. Maybe even with a few modifications to the Air Filter and Power Type still some achievement can be found.
A longer gearbox couldn't harm the GP1, with the original 125 gear ratio, Vmax is achieved at 110Km / h. Sufficient power to clearly penetrate into the range of 150Km / h is definitely available.
An Malossi Torque Drive has already been installed. Faster throttle response from narrower corners and better acceleration result from this measure - an effect that can only be experienced on the road and that no test bench diagram reflects - so GOOD RIDE!