Wow! I'm jealous! (just kidding). I owned a 1970 Yamaha R5 and it was one of the best bikes I ever owned. Stoplight to stoplight almost nothing could touch it - even the legendary Yamaha RD400. This was the best wheelie bike ever made!
Been able to put a few more miles on the CB. We get teases of spring here, then temps just drop again to the 30's. At about 40 mph, I lose all sensation of how the engine is revving. Thank God for the gear indicator because the engine is so quiet and so smooth that I need to check which gear I'm in. All I hear and feel is the wind!
A Staintune muffler is of a similar style as stock- but looks better (slimmer) and gives the bike a nice deep growl without being loud or obnoxious. It also gives a nice power increase.
Keep your eye out for one to pop up in the classifieds or ebay- it will be well worth it.