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IF YOUR BORE IS 47MM, THIS WILL MAKE YOU A 90CC ENGINE

IF YOUR BORE IS 51MM, THIS WILL MAKE YOU A 105CC ENGINE

IF YOUR BORE IS 52MM, THIS WILL MAKE YOU A 110CC ENGINE

IF YOUR BORE IS 54MM, THIS WILL MAKE YOU A 117CC ENGINE

THIS STROKER KIT WILL LET YOU KEEP WHICH EVER 47MM OR BIGGER PISTON, CYLINDER AND HEAD YOUR USING NOW,, ON THE LISTED MODELS.

THIS KIT DON'T NEED THE PISTON SKIRT TO BE TRIMMED !!! THIS IS HUGE AS FAR AS LONG TERM DEPENDABILITY GOES.

THIS KIT USES BIGGER CYLINDER STUDS FOR THE ADDED POWER, 7MM HEAD NUTS AND WASHERS ARE INCLUDED. BECAUSE OF THE LARGER STUDS YOU MAY HAVE TO DRILL OUT THE HOLES IN THE TOP HEAD COVER TO 5/16" OR 8MM. IT IS VERY EASY BECAUSE IT IS ONLY SOFT ALUMINUM AND 3/8" THICK. THE HEAD AND CYLINDER HAVE BIG ENOUGH HOLES FOR THE BIGGER STUDS ALREADY.

WE HAVE INCLUDED 2 6MM NUTS SO YOU CAN USE THEM LOCKED AGAINST EACH OTHER TO REMOVE YOUR OLD 6MM STUDS.

THIS KIT WILL ADD A BUNCH MORE POWER, JUST BE SURE TO MATCH IT UP WITH THE CORRECT CARB AND FILTER TO GET THE MOST OUT OF IT.

BECAUSE OF THE STROKE ON THIS CRANK YOU MUST CHECK THAT THE CRANK WILL CLEAR THE OIL PUMP DRIVE SHAFT. IT DID ON OUR TEST ENGINE, BUT IT WAS CLOSE. IF YOU NEED TO YOU CAN REMOVE A BIT OF METAL FROM THE SHAFT.

YOU MUST USE A PISTON THAT WOULD/DID WORK WITH YOUR ENGINE BEFORE YOU ADDED THIS CRANK KIT.

ONE LAST NOTE, BECAUSE OF THE SPACER PLATE, YOU SHOULD RETORQUE IT AFTER YOU RUN IT FOR AN HOUR OR SO.

FYI

THIS KIT IS FOR THE 63MM TALL CYLINDER

THIS KIT HAS THE SAME DECK HEIGHT AS CRF50/70'S HAVE

THIS IS A TRUE LONG ROD STROKER CRANK SO EXPECT WAY MORE TORQUE AND A LONG DEPENDABLE LIFE (:

51mm_STROKER_KIT FOR_47MM+BORES XR50_CRF50 XR70_CRF70 Z50R_1988_&_UP 91_TO_94_CT70 (51/STROKER/KIT) exed sorry discontinued 51/STROKER/KIT