Crankshaft
- Thread starter pierodn
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grandpaul said:
+1
Slick
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- Aug 8, 2005
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pierodn said:
21
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- Apr 21, 2015
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I assume ALL P11 owners with their cranks in bits look up the inside of the drive side half to check that the sharp outer edge of the drill used to clean out the hole during manufacture has finished in the web area rather than the more common directly beneath the big ends outer 90 thou STRESS REDUCING radius where it forms a stress raiser sometimes resulting in te D.S. half becoming two piece more easily and taking lots of other parts with it as it breaks at high rpm or even at tickover when it takes the crankcases and other parts ...as we know onlyy tooooo well!!!!! I assume that the people responsible for this serious cock up were on piece work rates of pay and to do the drillling job correctly to the depth shown on the drawing took longer......plus quality control and inspection within the factory was vertually non existant so the cock up made its way into peoples bikes..... Personally I bet mismanagement knew all about it after a few cranks failed but as the failures probably occured well outside the warrenty period and many of the cranks had been reground then the grinder was blamed for not getting the 90 thou radius correct.....which is who we blamed TILL I had the crank examined by a friendy G.E.C. Senior Metalurgist who asked ' who is the idiot who left that stress raiser inside your crank at the point of maximum stress? ' As a friend who rebuilds and prepares Nortons and who won a few championships racing them said when I tried to tell him about the problem I thought I had discovered..... ' Oh did you not know about that problem....I thought you did... I have been removing it from my and customers cranks for years...they break if you dont'.
But do I care if your crank becomes a 4 piece lump.......keeps people selling stronger drive side halves when a simple removal of the stress raiser problem would ensure a stronger original D.S. half is not required.....ASSUMING a crack has not already started which will eventually lead to failure and the friend has the odd crank returned from the welder because inspection done before welding the big ends back to standard shows the D.S. crank half to be cracked and thus scrap.
But do I care if your crank becomes a 4 piece lump.......keeps people selling stronger drive side halves when a simple removal of the stress raiser problem would ensure a stronger original D.S. half is not required.....ASSUMING a crack has not already started which will eventually lead to failure and the friend has the odd crank returned from the welder because inspection done before welding the big ends back to standard shows the D.S. crank half to be cracked and thus scrap.
