The cylinder made of aluminum shows significant differences to the MKII.
Malossi 136 MHR in detail
- Aluminum cylinder with coated raceway
- Centered cylinder head with O-ring seal
- new piston type with a piston ring
- larger inlet
- three-part outlet
- changed overcurrent channels
Dared a clear step into the modern with the MHR Malossi. Thanks to the aluminum material now used and the hard chrome coating,
the cylinder can also withstand higher thermal demands. The entry area and the volume of the overflow channels as well as the inlet area have grown significantly.
Due to the larger overcurrent channels, the motor housing must be adapted from Malossi according to the enclosed instructions.
For the new, large inlet, Malossi also offers a new intake manifold.
The new shape of the nozzle is intended to avoid over-greasing in the idle area.
In the intake area, the redesigned piston opens up the cross-section for the fresh gases very early on through cutouts in the piston skirt.
As in a very early previous version of the 136 from the 1990s, the piston of the MHR is equipped with a piston ring.
The stable rectangular ring should be installed with the lettering in the direction of the piston roof.
Due to the increased duct cross-sections, the anachronistic CVF system is no longer required in the MHR and the piston skirt is therefore more stable.
Complete with ring, bolt and circlips, the MHR piston weighs 181 grams. This makes it relatively light despite the rather massive struts on the inside
The cylinder head is already known from the Malossi MKII.
With the MHR, too, a 1,75mm thick O-ring ensures a perfect seal to the combustion chamber and is very neatly centered over the cylinder bore via 4 points.
Malossi specifies a geometric compression ratio of 12,5: 1 for the MHR.
The combustion chamber is offset 0,6mm from the cylinder head sealing surface.
In addition to the canal cross-sections, Malossi has also done something on the control angles.
With an assumed piston clearance of 1mm, the MHR offers a sporty steering angle with a stroke of 51mm with 124 ° to 179 °.
The resulting outlet of 27,5 ° and the larger area due to the secondary outlets also appeal to performance-oriented exhaust systems.
With an outlet diameter of 28mm and a stud bolt distance of 56mm, many common, sporty exhaust systems fit.
With the press presentation, Malossi advertises the new MHR for the Vespa, depending on the exhaust system, with an output of 18-25PS.
Combined with the Franz and a 28mm or 30mm carburettor, we can also imagine a performance level of around 20 hp.
We would be happy to put your Malossi MHR to the test with us to find out.
Details at a glance
- New type with sturdy piston skirt
- a piston ring 1mm
- 181,5 gr.
- Aluminum with hard chrome coating
- Overcurrent channels "MHR"
- larger inlet area
- Bore 57,5mm
- Stroke 51mm
- Connecting rod 97mm
- three outlet channels
- Outlet Ø 28mm
- Stud spacing outlet 56mm / M8
- Stud spacing inlet 65mm / M6
- Cylinder base gasket 0,5mm
- Steering angle 124 ° / 179 ° (41mm / 30mm)
- Centering over 4 points
- O-ring seal 1,75mm
- CNC machined combustion chamber
- Compression ratio 12,5: 1
- Cover for direct access
- Seals for direct and housing inlet
- Stud bolts for inlet and outlet
- Gasket set cylinder, O-ring 1,75mm, base gasket 0,5mm