After 1956 or whateveritwas , you can see a semi circular bulge / raised whelt , for the BIGGER BEARING under the bottom corner of the timing chest .
However there is , or was , a ' special bearing ' to fit Std Shaft to small bearing case . Timing Side .
Early Cases shaft & housing , timing side , are smaller .
' Big Bearing ' cases run the same bearing Both Sides / Ends of the Crank .
Ball Races are LESS DRAG , ifya wanna gofast . Tho mightnt last as long .
Theallowing of whip actually likely prolongs case life , under severe useage .
Big Bearing Case .
The Casting Dates cast in , on Triumphs . say ' 59 ' or the like .
This hideously grotty crank , is the preferred ' Thruxton ' lighter snappier revier job , from around 1967 .
Wernt suitable for plodding old farts so discontinued . Resemble original P.U. Versions .