Discussion in '6th Generation 2002-2013' started by Def-E-nition, Mar 22, 2007.
Very interesting reading fellas. Thanks
Probably a carry over from 3rd and 4th gen carbed VFRs with PAIR. They ran completely off vacuum and would remain open just off idle. No electronic computer controls measure TPS or RPM to open or close the valve. So using a tail pipe sniffer to measure fuel/air mixture at the pilot air screw on the carbed bikes would give a misleading reading at idle and just off as well. You get an accurate reading of the mixture at cruising RPM and then into the main jet for the rest of the RPM range.
I've done the PAIR and "flapper" valve block-off mod and also removed the snorkel.
Smoother throttle response, bit more torquey at lower revs and sounds great when you open the throttle
Curious why no one mentioned this mod for the PAIR valve?
Disabling the PAIR valve altogether? Just curious of your thoughts..
I actually did that version of the PAIR disable for a while when I installed my PC3 before I had the time to do the full PAIR removal and blockoff. The PAIR valve and associated parts ARE still doing something (don't ask me what, I'm not that smart) if they are still installed even with the valve unplugged electrically. When I "disabled" the PAIR valve with the system still installed I got massive ammounts of decel popping and backfiring through the exhaust (not a bad thing actually, I really liked it). Once I completed the job of removing the entire PAIR system and installing the blockoff plates the decel pop/backfiring went away completely.
Furthermore, to really over answer the question. Many members here have removed the whole system to remove bulk, excess emmisions bs, and save a tiny bit of weight. Thanks for sharing the link though, do you know if that guy is a member here?? If not you should tell him about the site and get him in on the madness too!!
Also, I see it's your first post here, so :welcome:
Thanks for the info, disconnecting the PAIR connector made a slight improvement, the surging doesn't bother me that much, but I'll try disabling the hoses as well in the near future.
I still have the flapper valve/hose connected though. Didn't seem to do much difference (actually made it worse when disconnected)
I'm not so sure about the the ECU not utilizing the O2's sensors when the throttle is closed. On 2 occasions i have bypassed the O2 sensors. Both times, when starting the bike cold, it would not fast idle. This has to be because the O2 sensors are bypassed. Nothing else has changed. One assumes the wax valve is adding the same amount of added throttle opening for a fast idle but the mixture must be wrong for a cold fast idle cause the O2 sensors are not telling the ECU the air/fuel mix. Is it running rich or lean?
If the O2 sensors do have an effect at idle, I recall the bypass of the O2 sensors is done with 330 ohm resistors completing the electrical circuit. I assume to stop the ECU fault warning. What other effect may 330 ohms have. At 330 ohms, do they also set a constant air/fuel ratio, possibly on the rich side to help overcome the EPA leanness? Can the constant air/fuel ratio be changed with different resistor values? Where did the 330 ohms come from and why?
All very interesting (to me anyway), but my head is spinning with this stuff. It's never going to happen, but wouldn't it be great if the bike manufacturers who designed the bike and the programming etc, were to get involved with such forums and provide definitive replies as to the effect of the various engine management components, when they occur and how affected by tweaks such as to the PAIR valve or the O2 sensors.
I just want my bike to fuel and run properly, as it can and should. Hang on. It works fine above 5000 rpm. That's the cure. Keep it above 5000.
Separate names with a comma.