Apologies for total lack of progress in the last couple of months. I have been retired for three weeks so I have no real excuses. I'm just getting used to this business of being my own boss but the weather here has been horrible and my cramped workspace has prevented me from 'unpacking' the CB72 project from its winter residence.
First job will be getting the seat done. I have all of the materials but the seat pan still needs cleaning up and welding.
I have been busy helping a friend out with a Gilera 150cc single which ruined its big-end. That should be simple enough to fix but there are complications. Les wants to upgrade it to 175cc from 150cc (60 x 54 - sound familiar?). We could not find a flat-top piston with the correct deck height so I have settled on a Suzuki GS750 rod and a 64mm XL185 piston (+1mm gives 64mm) which gets the deck height somewhere close.
And the main reason for the big end failure, I think, is that the oil pump feeds the crank through a plain bush on the drive side and, I'm pretty sure, that bush was worn allowing oil pressure to leak away. I have to fix that next.
It's all good practice for some Honda crank modifications that I'm hoping to work on which will reclaim some scrap crankshafts and give them a new lease of life.
Back to the Honda soon....
G