09-05-2015, 10:17 AM
(09-05-2015, 08:40 AM)Siggy Javotnik_imp Wrote: Zombie post: I removed my O2 eliminator (resistor) and plugged the O2 sensor cable back in to the ECU. I found that (1) the PAIR valve mod gave me the tractability gains I wanted; and (2) that, combined with the O2 eliminator made the throttle's responsiveness too soft. Not snatchy enough, for lack of better words. I'll still hold on to the eliminator -- when the O2 sensor fails (and it will), I'll probably just plug in the resistor rather than dig out and replace the expensive O2 sensor.
I'd made the mistake of doing both mods -- PAIR valve and O2 eliminator -- at the same time. Once I realized I wanted more responsiveness from the throttle, I had to choose which mod to undo. The PAIR valve is [modified after comments below and reading the service manual] causing secondary combustion in the exhaust port, which makes for a hotter engine and headers, so I'd rather leave it plugged. The only benefit I can see to taking it back to stock (unplugged) is if I lived in a really cold place and only rode 3 miles at a time -- stock, the engine would warm up quicker. [Also, less chance of fouled plugs, especially on #2 and #3. Probably not a problem with this bike, but it sure was with my '79 CB650! In short, the exhaust port and headers will heat up quicker and be hotter with the PAIR valve stock -- because it's causing secondary combustion there. If plugged, no secondary combustion, less heat].
No problem, but I think what may have gotten you off course could have been confusing the PAIR system with the EGR (Exhaust Gas Re-circulation) systems that carbureted cars used to use.
If you check your service manual, you can see the plumbing required for the PAIR system to take filtered air from your air box (not super-heated exhaust), then inject it into the heads AFTER the exhaust valve. This clean, relatively cool, oxygenated air, when mixed with the heat of the exhaust, helps to burn off the noxious fumes the EPA is worried about. This burning (actually small explosions) takes place in the exhaust, which is the reason for decel popping.
After seeing how the PAIR system works, it should also be the case that doing the PAIR Valve Mod would have little to no effect on how fast your engine warms up (other than the exhaust system getting hotter with the PAIR system functioning). The use of the O2 Sensor Eliminator Plug, however, may affect warm-up time as it should richen the mix at idle and low end. Then, after the engine is running well, the richer mix should actually allow the engine to run cooler and more efficiently (but, not 'efficiently' according to the EPA!)