Not homologated on public roads, only reserved for competition such as the MHR GP 80 and the super motorcycle trophy, the races for which this high engine was created.
Here is the very last MALOSSI MHR TEAM 80cc, this cylinder is already the must for years… This new version is reviewed and corrected! As usual with MALOSSI MHR, the finish is flawless, each part has been over-studied ... This kit is even more efficient than its predecessor thanks to a huge exhaust bar and 7 intake transfers instead of 5 in from before!
This cylinder uses the perfect core of the famous BIG BORE 77cc on a scooter! The diagrams are also revised upwards (everyone found the old team slightly too torquey despite the high speed). The exhaust diagram is pushed to 195.5 ° against 189 ° for the euro 2 version! Admission therefore goes from 5 to 7 transfers but also from 129 ° on the euro 2 version to 132 ° for this euro 3 and 4 version! Obviously the compression ratio is very well suited with 1: 15.8 and 5.3cm3 of chamber volume. Something to make you think about saying goodbye to your DERBI euro 2 engine ...
Malossi has yet to strike very hard! For the moment, no cylinder is capable of achieving such performance on mécaboite in this category. With its diameter of 50mm this cylinder offers real 78.50cc on 40mm original stroke. We strongly advise against imagining this kit on a long stroke, the diagrams would be so high that the loss of power would be considerable. The channels are perfectly created and studied, to our surprise, unlike the euro 2 and am6 models which preserved the size and shape of the original base, this cylinder has a new transfer design in order to improve performance, sweeping ...
For the best you will have to align the transfers to the engine casings. The cylinder has one of the highest-end nykasil treatment on the market, the piston has a very high silicon content and an extra fine single segment (0.80mm) domed hard chrome to allow the highest speeds and very low wear ... The cylinder head is a stud model, in bi-part in order to be able to improve the cooling as much as possible, the combustion chamber is a frustoconical model with a polished finish. You will tighten the cylinder head stud without the cylinder head cover! This technique makes it possible to carry out ever more precise tightening! Especially on a cylinder head stud with machined finish, reinforced MALOSSI MHR studs, special reinforced MALOSSI MHR nuts.
Obviously, this cylinder head stud has a lip and the cylinder too in order to be sure that the combustion chamber is always centered on the cylinder. In short, this cylinder is a performance monster! Certainly the best of all mécaboite kits at the moment ... No complaints about this kit put has by the segment junctions which are in front of an intake light. However, you should be aware that this kit needs to be accompanied by an adequate configuration! The must of mécaboite kits finally has a name, we will call it MHR TEAM 80cc for DERBI euro 3 and 4.
Description MALOSSI MHR
MHR THERMAL UNITS decomposable cylinder head
The new thermal units MHR CULASSE DECOMPOSABLE are the natural evolution of the MHR MALOSSI line. Fruit of the research of its technicians, they are at the origin of the victories of the official national and European teams in the cross and speed trophies. Malossi is happy to guarantee to all the pilots who want to participate in the National and European Trophies, a product worthy of a very high quality and performance.
CYLINDER
- Material: special aluminum alloy with a high percentage of silicon and titanium, which guarantees a very high dimensionality even at high temperatures.
- Heat treatment: special heat treatment of quenching and stabilization, which on the one hand gives the material high toughness and excellent rigidity, and on the other hand gives the mechanical and dimensional characteristics a constancy of up to a temperature of 250 ° C.
- Machining for the elimination of trimmings: carried out on numerically controlled machining centers with very strict dimensional and shape tolerances (cylindricity, roundness, perpendicularity).
- Transfer on the internal surface: executed with transfer of silicon carbides on nickel matrix, treated with a thermal process which guarantees an extremely high hardness (approximately 600 HVD, 1/5) with a very high resistance to wear.
- Internal machining of the cylinder: with special machines which make it possible to obtain a level of finish on the sliding walls with crossing of the roughness according to the angles established during the design phase (oiling).
- Exhaust diagrams and openings: studied and produced expressly for competition. The definition of the exhaust and openings diagrams required considerable work on the part of our technicians on the static engine test benches and on the competition tracks on which the trophy takes place.
PISTONS
- Materials: special alloy with a very high percentage of silicon, to guarantee very good resistance to heat and undeformability to temperature variations.
- External coating: graphite transfer which guarantees a very low coefficient of friction.
- Structure: reinforced to withstand the stresses that a thermal unit intended for competition at the highest levels must undergo, but at the same time very light to be able to reduce inertia forces.
SEGMENT
High mechanical strength spheroidal cast iron ring with additions on the contact surface, hard chrome anti-wear ground and lapped.
CYLINDER HEAD
The new decomposable Malossi cylinder head has been specially designed to ensure the evacuation of the immense amount of heat that develops in a very high specific power engine, intended for competition.
It is composed of a cylinder head in special hardened and tempered aluminum alloy with a high silicon content, attached directly to the cylinder liner which is covered over its entire external surface by coolant, which ensures a very large surface area. exchange. In addition, since it is free with respect to the external wall, it can follow the expansions of the cylinder.
The combustion chamber is entirely made with numerically controlled machines, in order to guarantee dimensional and shape tolerances to the nearest hundredth of a millimeter.
A cover completes the decomposable cylinder head system, which closes the upper part of the cylinder, for better retention of the coolant.
The combustion chamber of this thermal group has been expressly studied both from the point of view of geometry and squish for use on the occasion of the Scooter Speed Trophy and the Scooter Cross Trophy.
We recommend this kit with at least : reinforced crankshaft (MALOSSI MHR recommended), adapted exhaust (MALOSSI MHR GP 80 recommended), carburetion Ø26 to 30mm, reinforced bearings, cold racing spark plug (iw34 or w34 es-zu) racing ignition ...
The pack contains :
X4 cylinder studs
X4 cylinder head nut
Cylinder head stud
Cylinder head cover
Cylinder head cover screws
Complete seal pack with squish base seal
7 transfers cylinder, exhaust bar, Ø50mm
Piston Ø50mm axis 12 high treated silicon content
Ø50mm X 0.80mm hard chrome domed segment
Reinforced piston pin
C-piston clips
Cylinder head bleed screw
Notice
Stickers
...
Spare parts :
Piston
Segment
Clips
Axis + clips
Cylinder head cover
Cylinder head stud
Bolt set with purge
Set of studs + nuts
Complete seal kit
As an option we offer a stage 1 preparation, this preparation is a modification of the channels and the exhaust port by increasing the diagrams and improving the duct, it increases the performance of the cylinder. An improvement to the piston and the bottom of the skirt is also included in this modification. Allow a little extra time for this preparation!
