By far most important pin to replace in these 2t bicycle engines, the key to a long lasting strong crankshaft.
To install you would press apart any 66/80cc yd bt … crankshaft, then replace the original low quality hollow pin with this solid one. Please see YouTube for more detailed instructions.(search how to rebuild a 2t crankshaft)
Why this is necessary? The factory in China manufacturing the crankshafts puts a lead in slip fit diameter on one side of their pin allowing significantly faster assemble, unfortunately this also means a less resilient crankshaft especially when power level is increased. Additionally the pin is slightly undersized it’s entire length and the hardness is inadequate which often leads to bearing failure.
These pins are top quality special order pins made to exacting tolerances, all RDM Crankshafts utilize this pin.