this is the parts page for the rear pegs. It appears everything is available except for #29....this is new parts source...there are other sources for parts, new and used.....so begins the fun of owning a vintage bike.....
also, there is an additional reason for keeping rpm's up. The charging systems on these vintage 500/550's were not known for robust charging systems at the lower rpm's, especially when they went to mandatory headlight "on" in the mid 70's. So, yep, they like high rpm.....
...and I remember when I had my new 76 560F in 1976, It would wallow when pushed hard into the corners on the stock suspension....eh, 1976......
the honda middleweight 4's were and still are a great looking and fun riding bike....good memories...