Hi,
I guess you use C3 bearings ?, if not I strongly suggest them.
Jensen
CB72/77 Crankshaft bearingssixtiesscycle wrote -
I guess where I'm going, the Brit bikes turn a slower rpm than the Jap bikes. Now you are taking a smaller bearing and subjecting it to a higher rpm. Just thinking............................................. Have you not seen the size of the other bearing on the other end of a CB72/77 Crankshaft mine were both roller bearings - LEFT SIDE 6063 77mm DIA / RIGHT SIDE 6206 65mm DIA so this one is a lot smaller in diameter. Just checked out the spec on this bearing - Inside Diameter (d) 30 mm Outside Diameter (D) 72 mm Width (B) 19 mm Dynamic Load Rating: 29.6 kN Static Load Rating: 16 kN Fatigue Load Limit: 0.67 kN Reference Speed: 20000 r/min Limiting Speed: 13000 r/min
Okay you got me : ) Thanks for the bearing info. I haven't looked at a crank in a while but have a few readily available, I'll take a look. Dick Johnson
'61 CB92 '63 domestic CL72 Type 2 '63 CL72 '65 CL77 '66 CB77 '67 CB450D '71 SL350 '71 XS1B Interesting discussion! The drive side bearing is larger usually because it has to cope with extra load from the primary drive. i.e. the pull on that chain needs to be supported. The alternator side bearing only needs to support the out of balance loads (crankshaft rotation).
Bearings experience greater centrifugal load as the speed goes up and a smaller diameter bearing experiences less load. As usual, it is a compromise. The wonderful thing about working on these old bikes is that you are free to make your own decisions and compromises... I picked up this unstamped crankcase a while back which incorporates both of Hondas solutions for the alternator side bearing lubrication. It is designed to work with roller and ball races on that side which have different requirements.  G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F Them crankcase looks like a early one with the breathing tower on the top, I think Honda got there knickers in a twist with that alternater side bearing my 1964 case has a oil feed hole that is covered by the ball bearing race when fitted or should it have a roller bearing I thought the roller bearing was fitted to the very early bikes, this make sence as it's cheaper to fit a ball than a roller bearing.
And to top it all my ball bearing race has a 6mm hole and the knock pin is stepped down to 5mm this gives the bearing plenty of room to move about so that knock pin is not there to hold the bearing. And what is that little channel for ? oil one would think. Well I will remove any seals on the bearings i install on that side. So right more questions than answers perhaps Honda wanted to discourage any one in the future from restoring any of there bikes cunning them Japs. There was a time when Honda when asked if they had any of there old GP bikes and they said no Honda has no time they do not look back only look forward that was quite a time ago, when the retro lark started they soon changed there mind when they set up a museum and scoured the world for old GP bikes to fill it. What about a modern CB72/77 Honda.
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