At the inception of the Stock Honda class, there were several pipes that were legal…. The RLV, RCE, and I believe a High Tech and McMillan…
The RCE quickly became the pipe to have, and I’m sure Mr RLV wasn’t happy with that, and either he had the R4 added, or somebody else did to compete the RCE. That was a good thing, because shortly after RCE went tits up!!!
It’s really not a “spec” series, because they are not sealed motors, and some different parts are allowed in some areas, pipes and fuel systems being some of them… I think that’s one the keys to it’s success, they are not exactly cookie cutter motors, a little different here and there, enough to keep everything interesting…
Just my $0.02….
CR