Sleep Mode??

I recently purchased a 2005 VFR800 and have spent many hours researching information from other owners to help improve the bike. I completed all of the typical modifications such as O2 delete (did this myself), disabled the flapper valve and removed the snorkel. I also recently installed a Scorpion exhaust and a 15T front sprocket.

The two major issues that I'm noticing since making the changes are:

1. Fuel delivery in the lower RPMS (around 4k in 2nd gear) when just riding in town is very abrupt. There's a huge lunge forward on deceleration and it's just about impossible to get back on the throttle in small increments without a big surge of power. It just makes in town or in traffic riding very choppy and uncomfortable.

2. The second issue, which is really noticeable at highway speeds, is what I call the "Sleep Mode". When cruising at a steady speed in the 5k - 6k RPM range the bike just suddenly starts losing power. I'm holding the throttle at a constant position and I'm feeling the power slowly fading and watching the RPMS slowly drop. A slight twist of the throttle wakes the bike back up. It's almost as if I need to be constantly accelerating, I can't just stay at a steady speed.

Can anyone give me an idea of what I can do to fix this? I'm thinking the next step is a PC or one of the other piggy back style fuel management, but is that going to correct these issues? Wasn't the O2 delete supposed to get rid of that power lose when holding a constant speed in that RPM range?

Any help would be greatly appreciated.

Patrick

 

Hello patrick78

First issue: There are many forum post about the 6th Gen VFR's poor fueling quality at low speeds & how PC's can cure this issue. A simple search of the forums & you'll have more info than you know what to do with. PC's also help smooth out VTEC transitions on earlier 6th Gen bikes. Forum member Stewartj239 had a good post on his experience with a PCV & how it corrected the low speed fueling issues for his 07.

Second issue: I don't see how you can delete the O2 sensors, not remap the bike & expect it to run properly. Did the bike have this problem before you did this mod? Did the previous owner do any mods that your unaware of?if it is easy to return to stock try that then see if the problem is still there.

My 2007 VFR had a problem that is exactly as you describe for your 2nd issue. I purchased the bike new as a leftover in Jan 2011. I didn't have to spend anytime riding the bike to know the stock grips had to go. So I put on a set gel Pro Grips. Once riding season arrived all was good at first. Then I found I had to keep twisting the throttle to maintain a consistent speed. I though the worst at 1st since I bought an 07 that had been sitting for 4+ yrs. It turns out that the adhesive I used on the grips wasn't strong enough. The right side grip was spinning around the throttle tube. The problem was more noticeable in warmer temps as the adhesive would loose it holding strength. I could accelerate but not hold a steady speed.

 

:welcome: to the madness
+1 to the above suggestion :thumbsup:

 

Thats a first...never heard of the grip slipping like that...ever

 

Thanks for the responses guys.

For the first issue, I was basically just following the information I found previous posts about these pretty standard mods to the bike. And to be honest with you the bike feels different to me just about every time I get on it. It's almost like it changes how its running on its own. But anyways, my next step is to pick up a PCV and hopefully that will correct the roughness of the fuel delivery. I've already read plenty of posts on that subject as well.

The second issue is definitely not related to the grip sliding on the throttle. I also a Throttle Rocker and that never moves so I know the grip isn't turning. I thought that the O2 delete was supposed to get rid of that the bike flat spot or surging in the mid-range. I read that in this post from a thread about making your own O2 deletes.

"It is thought that eliminating the o2 sensors cures that midrange surge or flat spot in the power-band. It is essential to eliminate the sensors when using a PCIII or you will get FI errors. Using an aftermarket silencer some have had success in curing the surging by eliminating the O2 sensors. When in constant throttle the ecm puts the fuel curve into stoichiometric mode and it burns with lower emissions, saves fuel, this seems to produce a flat spot or a surge when coming out of it."

Hopefully the PCV will clear all that up and smooth out the power delivery from idle to Vtec.

 

With the bike being FI, when you removed the 02 sensor without having the PC on there and being mapped, you've basically thrown the computer for a loop. I would guess the reason you're bike feels different "every time" is relevant to everyday changes - how warm it is, how cold it is, what's the humidity outside, what's the barometric pressure doing, are you riding in the mountains or the city, blah blah blah. Your system is continuously "hunting" for how it should be running with air and fuel ratios.

 

Thats what happens when you use an adhesive in the middle of January. Lesson learned.

 

+1 to Pliskin.

Patrick78 if you did the 330 ohm resistor trick, re-connect or install your O2 sensors until you get your hands on PCV.

 

Thanks guys.
Pliskin: What you said makes perfect sense. I could have sworn while reading all of the PCV posts that there were a ton of people that were asking about the benefits of getting a PC, but they already had all these other mods done. I'll probably be the end of next month before I make the PC purchase so I'll definitely reconnect the O2 sensors for the time being.

Thanks again all.

 

weird i ran the 330 ohm resisters for a couple months before i got a pc and it was fine. i mean it was a much better bike with the power commander, but it wasnt too bad. still much better than stock.

 

I don't think he had the resistors installed, though.

 

Lol WhyTF would any one do that?
I hope he wouldn't.
I'm pretty sure that would throw check engine lights.

 

I did have the resistors installed. I removed them last night and rode my bike into work this morning. Much better! I think the reason the bike wasn't running badly when I first installed the resistors is because the temperature was still cool here. This week it's been close to 100 degrees every day so there's been negative effect on how the bike is running. I'll just leave the O2 sensors installed until I'm able to pick up a PC.

 

patrick78, so what was the eventual outcome? Did you pick up a PCV? All better? Still losing power at constant throttle?

 

Signal: I actually just picked up a PCV and installed it yesterday. The difference is so tremendous Im not sure I can even put it into words. Fuel delivery is so smooth from idle to redline. No more sleep mode in the 5k range. And no more fuel cut off when you close the throttle while riding.

I picked the pcv up from Fuel Moto based on an older thread. They ask your bikes mods and install a tune that best fits those parameters. It even had a sticker on the box saying that it was retro fitted with a PC3 tune since my bike is a 2005. Id definitely recommend purchasing from them.

Thanks all for the responses to my original post and for such a great site full of tons of information.

 

Did you get Autotune on your PCV?

 

I too have been a victim of Loose Grip Syndrome. Operator error during installation was to blame. Made long slab rides quite tiresome.

 

When putting new grips on, I wrap the bar (or throttle tube) in a single layer of electrical tape- not doubling over on itself when wrapping, to keep it thin.

Then I put a little gas on the tape- just enough to get it wet, and a little gas inside the new grip.
It makes it slippery enough to slide on easily and adjust as needed, then the gas evaporates, and it all sticks together.

This has been my only method of installing new grips for over 40 years, and I've never had a grip slip yet.

 

Hairspray works good too. I just bought new grips, and honda grip cement. With the cement applied, grips go right on. Then after a short time it hardens and the grips aren't going anywhere.