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Big end bearing sizes for a Type one
Craig Torrens - November 23rd, 2011 at 09:40 PM

What is the largest "under sized" big end bearing for a type one crank ?

I've heard they go up to 2mm under sized, but that sounds extreme !!

matberry - November 23rd, 2011 at 09:52 PM

My 1st thought and 1st check in a suppliers catalog goes to +1.5mm

Craig Torrens - November 24th, 2011 at 02:53 PM

cheers

psimitar - December 3rd, 2011 at 11:01 PM

the 2mm is only for the thrust bearing. Journals I though only go to 1mm as beyond that there is no casehardening left on the crank.

Yea, just checked and 1mm crank, 2mm crankcase and 2mm thrust.

matberry - December 4th, 2011 at 07:37 AM

I think you'll find 1.5 BE bearings. Mains come in up to 2.0mm on the back (case) and .75mm on the crank. Re-nitriding is possible to re-harden the crank. This is done to all modified and some reground cranks if done right as the nitriding is only around .005" deep (iirc).