Latest advice re O2 sensor mod requested

[Rodzone]

On the 2010 800 VTEC with only the flapper solenoid disconnected, snorkel removed and PAIR plug separated, is there any point pulling the sensor plug apart and putting the resistors in?

 

I did notice some rideability improvement with the first three mods.

[Rogue_Biker]

I would connect that flapper back in so you get your mid-range power back.  That's what the flapper valve is for....restrict air flow at lower RPM to increase intake velocity.  But when you go to VTEC and the engine needs more air, the flapper opens and you get all the flow the engine needs at higher RPM and bigger throttle openings.

 

02 Sensor disconnected will force your bike to run in closed loop mode and not go to the very lean stoichiometric mode designed for the least exhaust emissions at part throttle.  This lean running at part throttle causes the surging on the 6th Gen bikes.  It goes to very lean as the ECM reads the o2 sensor at part throttle to reduce emissions.  This results in your bike slowing down slightly.  You then re-open the throttle to gain back the speed before it went to lean mode, and the bike shoots fuel back.  Repeat.  Thus, surging.  It also makes low speed riding at low RPM a herky-jerky affair.  A gift to you for saving the planet from the evil exhausts of motorcycles.  

[Rodzone]

Thanks, just done the O2 it and tested it.  Everything you say is true.  Can now sit on a given speed without hunting up and usually down.  Another improvement!

[Rogue_Biker]

The single BIGGEST improvement I got from my motor was fitting a Power Commander 5.  I previously had a PC 3, which was still way better than stock, but the 5 took it to another level.  Even smoother throttle response all the way down to idle.  I can put my bike in 1st gear, release the clutch and let it propel the bike at near idle, make sharp U-turns, etc.  without touching the clutch.  From there I can pick up the throttle and smoothly accelerate away.  It does help to have a nice, tight-spot-free drive chain.  

[Rodzone]

I got another improvement in the same way of pickup from idle being smoother by taking most of the slack out of the throttle cable.  A PC5 only if I decide to keep this bike long term.  I'll put the flapper valve back to normal and see if I can notice a difference per your advice.

[Rodzone]

So I put the snorkel and flapper valve back to standard, plugged the PAIR back in and now am just running the home made 02 sensor delete with the sensors still in the exhaust.  Will test and post again.

[Rodzone]

I have set out my findings in the 4 cheap mods post above

[Rogue_Biker]

The homemade O2 Sensor delete is BETTER than keeping it.  It eliminates that Stoichiometric condition that the stock ECM forces on the fueling and gets rid of the surging AND lessens the harshness of the VTEC engagement.  The PC5 eliminated the VTEC abruptness altogether.  The engine just transitions to VTEC smoothly no matter what throttle position it is.  I remember thinking it was an all new bike!  I'm sure this is how the Honda Engineers intended it to run but just couldn't get it there in order to pass Emissions.  Every single manufacturer of bikes had to deal with this when they all transitioned their models in 2008.  Honda just did it that "transition" in 2002 with the then-new 5th Generation VFR800.