Attention, part not approved on the road, reserved exclusively for circuits, runs… for competition.
Here is a totally exceptional kit, although it has already existed for a good number of years, this kit has never been copied or equaled in terms of engine displacement ... Indeed, with its diameter of 55mm and its crankshaft stroke of 46mm, this kit offers no less than 109.28cc real! The 90mm connecting rod offers less pre compression because the piston / cylinder is 5mm less close to the lower engine compared to the 85mm connecting rod model.
In addition, the throttle path is also shorter on the 85mm connecting rod model than on the 90mm connecting rod model. However, the 90mm connecting rod model will release slightly more high speeds (less connecting rod forcing). The 90mm connecting rod also makes it possible to reduce the acceleration speed of the piston (modification of the motor movement).
The assembly is completely possible on DERBI euro 3 and 4 but be careful, you will still need tools and good mechanical knowledge bases! Machining to pass the compulsory cylinder base, to pass the crankshaft as well, compulsory engine preparation in order to align… The assembly will not be a simple assembly of parts but really a complex work which must be carried out properly.
PARMAKIT studied the part for a long time before taking it out, they certainly put a Ø55mm bore in this cylinder but the skirt thickness is still very correct from a solidity point of view (2.25mm thick). This large bore obviously requires a long stroke to speak ... However this d.55mm kit also exists for short stroke 40mm!
Despite the 46mm stroke planned for this cylinder, we are moving away greatly from the so-called square motor! Very high revs cannot therefore be reached, we will play on the torque to the extreme. The cylinder has been very worked, 6 intake transfers are present, two for the rear (we all know that the rear transfer is almost only used for valve activation and scanning ...), the laterals are therefore in number of 4 and they are very bulky, increased on the low front like most major brand hyper racing cylinders. Exhaust level, PARMAKIT has opted for the booster exhaust, it is the most adapted to the torque of the beast, a large very well designed booster exhaust is therefore on this cylinder. The piston is a true vertex in single thin segment (1mm) in order to release the high speed. It is a piston with a low domed cap.
This cast piston weighs 141 grams (complete with axle / segment / clips). For the cylinder head, it is necessary to extract the heat from this thermal unit (especially given the 46mm stroke which further increases the heating) PARMAKIT therefore opted for a stud cylinder head. Head stud machined in high-end aluminum, the chamber is a model very well suited to the piston / cylinder, its shape is hemispherical with a polished finish.
The stud is entering in order to be sure that the alignment is always good to the tenth. The incoming stud also avoids breakage of cylinder head gaskets! The cylinder head cover is also very well designed and has excellent support! Anyway… We could spend hours telling you about this pretty monster that the great PARMAKIT brought out to us, this kit has really been neat until the comma cut of the skirt for the improvement of the filling ... Everything is really a set of quality, neat, of great study. We also strongly appreciated the well-defined diagrams in relation to the whole.
We recommend this kit with: PARMAKIT crankshaft 46mm stroke 12mm axle 90mm rod, racing cold spark plug, 100% synthetic racing engine oil, 28mm minimum and quality carburetion with valves / pipe ... Reinforced bearings, good cooling, complete preparation, efficient ignition, clutch well reinforced, cold spark plug, racing exhaust to be defined ...
The pack contains:
- Cylinder 6 aluminum transfer nikasil Ø55mm for 90mm rod 46mm stroke
- Cylinder head stud
- Cylinder head cover
- VERTEX mono segment piston Ø55mm
- Ø55mm X 1mm hard chrome domed segment
- Piston pin Ø12mm X 42mm
- Crab type piston clips
- Pack joint with 4 base gaskets for squish
- Installation instructions...
- 4 Studs M7 X 130mm
- Aluminum base wedge 4mm thick
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!
