® Valve recession

One of the truly unconscionable shortcomings on the sohc4 forum is the insidious and ignorant rejection of the very real and overriding issue on single-cam Honda four engines of valve recession and its effect on cylinder compression. There is no more important issue, yet the forum not only ignores it, but conjures up utterly facetious alternate realities to explain its consequences.

Honda put soft valves in all the early fours. No one who has worked with these bikes for any appreciable time can be unaware of this. I have written of this elsewhere, but you need to accept this fact and understand how it affects your vintage Honda four's performance. That is, much. You can't expect good cylinder compression if you machine has over 15,000 miles on its engine. And it affects the way in which this engine should be tuned and the way it is best rebuilt.

 

Further reading:
The truth about compression
More about compression


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