Originally Posted by biknut
... If the rod isn't perfect, the needles will fail. that's what happened with this motor.
IMO our biggest challenge is getting a china girl with a good crank.
you're absolutely right! That is what we should shout every day in the direction of China's manufacturers.
In an upper answer you've said that INA comes from China. INA is a worldwide producing company with the main factory in Germany. They make needle bearings, special piston pin bearings and special conrod big end bearings.
For my American friends I have been looking for INA's specification in English language about how to manufacture a connecting rod and the permitted tolerances. Here it is:
Twostroke crankshafts which are manufactured according this specification, will carry you once around the world. At least half, as one would expect as a customer.