Motorcycle Repair: CB350 cam case oiling.., drive gears, gasket material

Question
Hi Bill, I have another question re: early 70 CB350's.   I replaced rings on my old 1970 350, and when inspecting the cam case I saw that there was an oiling hole in each of the places that accepts the rocker arm stud/adjuster. (the things with the eccentrics on them, I don't know what they are called) Anyway, I have since found that the later models (specifically the 72 in this case) cam case has only three oiling holes where the rocker adjusters go, with the front right side having no oiling hole.  Why is this?   Does that part get sufficient oil through another means?  Might it be oiling through the cam end holder (that has the tach gear in it)?  
Very confusing to me, since it looks like three get oiled well and one does not.  

Can you help?

Thanks...

(sorry I dont know the names of these parts..


Answer
Patrick, my 350 twin books are all in storage awaiting a move next month. Rest assured that Honda has properly figured out the oiling system to the top end, even when it isn't immediately evident. I think your observation about the tach drive on that corner is accurate.The tach drive gears have to have steady oil flow, so I think that it is just branched off there to the rockers. With no oil flow to that rocker arm adjustment shaft, there would be seizures of the parts in a heartbeat. Sometimes the oil holes are cross drilled and plugged so oil is moving laterally through the parts, instead of just up and down.

I once wrestled with a CB350 that kept seizing a camshaft bearing, usually within 3 minutes, due to lack of oil. Turned out that a tiny piece of side cover gasket material had broken free and floated up the oil passage, enough to block the oil flow to the bearing. There is a Honda bulletin on this issue, that I discovered years later.

If you look closely there is an oil passageway from the cylinder head feed hole on the left, through the cam case and to each bearing and shaft. Oil feed is critical to the shaft/rocker interface, of course, and not necessary for the outer end of the shafts, which are stationary. Honda shop manuals show the oil flow pathways from the pump all the way through the motor.

Bill Silver