Racing crankcases Derbi euro 3/4 WF-R Bidalot

Bidalot WF-R racing crankcases for Derbi euro 3/4.

As expected, the Bidalot engineers have designed and manufactured these innovative crankcases for Derbi euro 3/4 engines, they have modified the intake to install large carburetors with a short intake manifold, on the other hand they have modified the crankcase to install crankshafts up to d.84mm.

Undoubtedly, if the entire set of crankcases, exhaust, gearbox, etc. is installed, it can be a great project for circuit.

Technical specifications

COMPATIBILITY

• Distance between front and rear center identical to the original
• Mounted on chassis without lower cradle and without lower engine support
• Compatible with all Derbi euro 3/4 engine parts
• Increase of the central distance between the crankshaft axis and the primary axis to allow the possible installation of large diameter crankshafts

CYLINDER

• Adaptable to Derbi euro 3/4 or FL cylinder
• Cylinder inclined 10° forward

CRANKSHAFT

• Crankshaft crankcase machined to d.79mm to install counterweights d.77mm
• Possibility to machine up to d.86mm, to install counterweights up to d.84mm

INTAKE

• Honda CR85 VForce 3i / Vforce 4 reeds box reference: V4R81A
• VForce 4 reeds box for Yamaha Banshee can be installed by machining the crankcase
• PWK 28 to 38 carburettors without large intake manifold
• Manufactured with a hole / plug to fit a vacuum port if a mechanical fuel pump is used.

TRANSMISSION

• All original Derbi parts are used, gearbox, selector and clutch.
• The oil levels of the gearbox and the transmission are separated and have been optimized to limit splash losses. The gearbox oil level is 0.15 l. The primary transmission oil level is 0.12 l.
• Clutch bell CNC, pinion and primary drive gear, ratio 20/73
• The transmission cover is equipped with a removable cover that allows quick changing of the clutch discs

BALANCED SHAFT

• Adjustable balancing shaft, with additional counterweight, to suit each displacement.
• Different counterweights

IGNITION

• The ignition plate, which also acts as a support stop/lip seal and crankshaft bearing stop, has been designed for mounting the PVL flywheel, with centering of d.90mm

COOLING

• It is necessary to use an electric water pump reference: VCR-RD09.PUMP

ATTENTION ADDITIONAL MODIFICATIONS

• Modify the chassis, if necessary, by removing the lower cradle and its central mounting support
• Check and, if necessary, adapt the silencer to the new angle of the Cylinder
• Shorten the secondary shaft by removing the spring from the pinion-kick assembly
• Use an electric water pump

Assembly instructions