BIDALOT description:
Here is our latest top end, RF50WR, in Racing version, for DERBI E2 (EBS) engine.
This high-performance top end can only be fitted with a 39.7mm stroke crankshaft and an 85mm connecting rod.
The valve timing and compression ratio have been set to achieve the best performance. However, to operate optimally, this kit must be used with its exhaust Ref 150 00 588, the Racing Factory ignition 140 00 382, and a Racing intake (Vforce3i Honda CR reed valve + KEIHIN PWK Ø28 or Ø30mm carburetor).
It is therefore recommended that an informed public, with the technical skills to develop this type of configuration, and to assume responsibility for its maintenance.
We do not recommend it for all-day use, and highly recommend the adaptable version!
Fully modeled in 3D CAD, the cylinder has its water chamber surrounding all the transfer and exhaust cores, with constant thicknesses, capable of guaranteeing high dimensional stability of the cylinder, due to optimized cooling.
The heat-treated cylinder head also features a water jacket surrounding the combustion chamber for efficient heat dissipation and optimal cooling. It is self-centering within the cylinder and extends 2.4mm into the bore on this version.
The specific exhaust flange is secured with 4 screws. However, it is possible to fit a 2-hole mounting flange with a 48mm center-to-center distance.
You will find exhaust flanges of various sizes sold as accessories, allowing for the adaptation of almost all exhaust systems on the market. These flanges are available in the following dimensions:
Ø28mm x L30mm
Ø30mm x L30mm
Ø32mm x L30mm
Ø28mm x L30mm Label (standard equipment on the RF50WR exhaust)
Technically, this thermal unit is composed of:
DERBI E2 RF50WR Racing top end:
Aluminum cylinder, with heat treatment, Nikasil coating Ø40mm
Aluminum cylinder head, heat-treated, self-centering and recessed 2.4mm into the cylinder, with high-compression combustion chamber. RF50WR hypersilicon piston Ø40mm
5 transfers
Booster Exhaust
New 2018 profile, elliptical, specific, to reduce operating clearances
Axle height 25mm
Chrome-plated steel segment Ø40x1, ground and domed, made in Japan
Axle Ø12x33mm
Set of base gaskets of varying thicknesses
Cylinder head O-ring set
4 cylinder studs
Various screws
Warning, you will need to modify your crankcases to fit this cylinder!
This top end is compatible with 50cc motorcycles with gearboxes equipped with the DERBI Euro1 and Euro2 engine:
BULTACO Astro enduro 50cc
BULTACO Lobito supermoto 50cc
DERBI GPR 50 Nude before 2004 (EBS050)
DERBI GPR 50 Racing before 2004 (EBS050)
DERBI GPR 50R Replica, model years 2001 to 2004
DERBI GPR 50cc, model years 1998 to 2001
DERBI Senda 50cc pre-2000 (tubular frame)
DERBI Senda 2000 50cc pre-2004 (perimeter frame) Euro2
DERBI Senda DRD supermotard pre-2000 (tubular frame)
DERBI Senda DRD supermoto pre-2004 (perimeter frame) Euro 2
DERBI Senda Enduro pre-2000 (tubular frame)
DERBI Senda R DRD Enduro pre-2000 (tubular frame)
DERBI Senda R DRD Enduro pre-2004 (perimeter frame) Euro2
DERBI Senda SM pre-2000 (tubular frame)
DERBI Senda SM pre-2004 (perimeter frame) Euro 2
DERBI Senda X-Race 2000 pre-2004 (perimeter frame) Euro 2
DERBI Senda X-Race Trail pre-2000 (tubular frame)
DERBI Senda X-Trem Enduro pre-2000 (tubular frame)
DERBI Senda X-Trem Enduro pre-2004 (perimeter frame) Euro 2
DERBI Senda X-Trem SM pre-2000 (tubular frame)
DERBI Senda X-Trem SM pre-2004 (perimeter frame) Euro 2
GILERA GP Replica 50cc
GILERA GSM 50cc
GILERA HAK Euduro 50cc
GILERA RCR Euduro 50cc (tubular frame)
GILERA SMT SM 50cc (tubular frame)
GILERA Sioux Enduro 50cc
GILERA Zulu Enduro 50cc
And many other models...
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