A superb ATHENA racing brand crankshaft, reinforced with studied solid masses (the piston descending +, we compress +), 43mm long stroke, 85mm connecting rod, for 12mm piston pin, it will therefore increase your displacement. You will need to assemble it with the kit provided for this purpose . The 85mm connecting rod (long) certainly reduces pre-compression but greatly reduces piston wear.
47.6mm kit with normal stroke crankshaft (original therefore 39.20mm) = 69.75cc
47.6mm kit with 43.00mm long stroke crankshaft (like this one) = 76.51cc
It is very well balanced, its bristles (bearing housing) are of original size. However, you will have to machine your crankcase in order to pass it. It comes with its reinforced needle cage, it also has a keying for ignition which is already readjusted in relation to the long stroke for more performance, the connecting rod is really reinforced to the maximum and over-lubricated. It is specially designed for the ATHENA d.47.6mm racing kit for long stroke but you can use it on another cylinder with a 12mm axis if you derive it, however be careful, the 85mm connecting rod with another kit will surely pose a problem. !
The crankshaft is digitally machined, the connecting rod, cages, masses ... are made of very resistant materials.
Photo of the machining of the left crankcase to be carried out:
summary :
-preparation of the large casings compulsory for connecting rod passage
- rod small end diameter 16mm
-inside diameter of the cage supplied 12mm (for piston pin 12mm)
-balancing: no
-stroke 43mm (long stroke)
- rod length between axes: 85mm (long rod)
-greasing head and connecting rod: yes / increased
-masses for pre compression: full
- silver foot cage reinforced d.16mm inter
- fine reinforced head cage d.12mm inter
- hardened steel masses
-NNC connecting rod reinforced on greased
-crankshaft bushes: normal, original size
spare parts :
-Complete connecting rod length 85mm axis 12mm
Mounts on :
APRILIA AMICO
APRILIA SR (before 1993 only)
FANTIC BIG WHEEL
GARELLI PONY
GARELLI SR
ITALJET BAZOOKA
ITALJET PISTA
ITALJET REPORTER
ITALJET SCOOP
ITALJET YANKEE
ITALJET ASCOT
ITALJET ASTRA
LEM FLASH
LEM GHIBLI
LEM TORNADO
LEM TORNADO SS1
KOTIR SR
KTM CHRONO
MBK BOOSTER
MBK BOOSTER NAKED
MBK BOOSTER ROCKET
MBK BOOSTER NEXT GENERATION (NG)
MBK BOOSTER CW
MBK BOOSTER SPIRIT
MBK STUNT
MBK TARGET
MBK BOOSTER TRACK
YAMAHA BW'S
YAMAHA BW'S NG
YAMAHA BW'S ORIGINAL
YAMAHA BW'S NAKED
YAMAHA CRZ
YAMAHA CT
YAMAHA SLIDER
YAMAHA SPY
YAMAHA ZUMA
And many other models
