09-07-2015, 12:09 AM
Thank you for walking me through that, and referring me to the service manual! Some kind soul posted the PAIR valve page on this site, here: http://i.imgur.com/cSu7e1X.jpg
On the CB600 forum, I also found this explanation, which made sense and explained popping on decelleration: "The system only activates under negative load (throttle down). this would not [a]ffect throttle up operation, which is what dyno tuners tune to, sooooo........"
In other words, unless I mind the popping from the Yoshimura slip-on that came with the bike (I don't) or am concerned about engine heat it's fine to just leave the valve as-is. And, of course, my idea that blocking the PAIR valve affected throttle smoothness doesn't make sense. The one way I've found to do that is the O2 eliminator, which has the fueling effects outlined expertly by Gumby 1100. This forum is great for this kind of knowledge, thank you!
p.s. Gumby was right, I have dealt with 1980's era automotive EGR. Although modern Triumph classics have SAI (Secondary Air Injection) with a port directly into the head that is maybe closer to EGR than Honda's PAIR valve. Removing SAI on a Triumph makes the engine run noticeably cooler and (seat of the pants) smoother -- but I've been wrong on that before, see above.
On the CB600 forum, I also found this explanation, which made sense and explained popping on decelleration: "The system only activates under negative load (throttle down). this would not [a]ffect throttle up operation, which is what dyno tuners tune to, sooooo........"
In other words, unless I mind the popping from the Yoshimura slip-on that came with the bike (I don't) or am concerned about engine heat it's fine to just leave the valve as-is. And, of course, my idea that blocking the PAIR valve affected throttle smoothness doesn't make sense. The one way I've found to do that is the O2 eliminator, which has the fueling effects outlined expertly by Gumby 1100. This forum is great for this kind of knowledge, thank you!
p.s. Gumby was right, I have dealt with 1980's era automotive EGR. Although modern Triumph classics have SAI (Secondary Air Injection) with a port directly into the head that is maybe closer to EGR than Honda's PAIR valve. Removing SAI on a Triumph makes the engine run noticeably cooler and (seat of the pants) smoother -- but I've been wrong on that before, see above.