Getting back to the original thread, the SOHC4 was designed, as were most engines of the 70's, for a certain kind of riding. That didn't include a Friday night traffic jam on the Cross-Bronx Expressway two up in 90 degree weather in July, believe me. One of the few accessories I ever added to my CB750 that helped it was (bless them) a Lockhart oil cooler, which I immediately updated to the thermostatic model as soon as it came out. I could get on a CB750 and tell you it had been ridden hot in 30 seconds as long as it didn't have a cooler installed back then.
Bear in mind the top-of-the-line motorcycle oil was Castrol 20w-50 at the time. No synthetics. And you couldn't use "viscosity enhancers", i.e. STP, because the SOHC was a wet clutch bike and it'd never stop slipping if you used that stuff.
My '70 SOHC was a whole new motorcycle after the Lockhart. And the next best thing was the spin-on oil filter adapter. I used to change oil that looked almost as golden as what I poured in from the can (oil came in metal and then reinforced paper cans) after the spin on. And the spin-on had about twice the filter area of the standard Honda toy filter which, to its credit, was more than any other standard bike of its day offered. Today I'd like to try the same combination with a heavier oil pressure relief spring; probably the ultimate combination for the street and/or sporting riding.
But I've seen as many high-mileage SOHC's that had no oil cooler and the standard oil filter. Honda made a relly bullet/idiot proof SOHC, no?
And just to be complete: my SOHC started out with a Bill Bowman deep finned oil pan, so I already had the state of the art in SOHC oil cooling BEFORE I added the cooler.