Attempt at consensus of VTEC fixes/improvements

Here are my .02 worth. I have an 05. I don't have any problems with surging. Activation of the VTEC can be either abrupt or smooth depending on the amount of throttle. The biggest thing I notice is the slight hesitation before the VTEC kicks in when accerating hard. I do have some jerkiness but that is mostly related to poor gear changing on my part. As I ride the bike more the changes are getting smoother. I suspect that part of the issue is that with the very free spinning nature of the engine it is hard to match revs for a smooth shift. So I don't really see the problems that others are talking about. I am just lucky I guess.

 

Heres my 2cents. My 2003 VFR had the same hesitation between 4-5k. I rode it that way the first summer I owned the bike. The hesitation was extremely annoying. I absolutely love the bike and knew there had to be a simple solution. It almost felt like it was running out of gas at certain times between 4-5k.

My solution was to buy a Fuel Pressure Regulator from Turbocity Tom (you can find him on the internet). The part was something like $90 and it cured 99.5% of the problem. I should mention that a buddy helped me synch the sv valves while the tank was up and I removed and plugged the pair valve. But I would bet that the FPR was the key to taking care of the lean condition the bike had between 4-5k.

Now I do not have the hesitation and the vtec transition is way smoother. It's almost like it is a new bike. Couldn't believe it. It basically just richened the mixture and cured the lean condition. Maybe not the best way to fix the bike, but I did not have to buy a $300 computer and monkey around with fuel maps to make my bike run smoother. I also did not notice any loss of fuel mileage and wouldn't care if it did.

 

The lack of flywheel effect is causing me to make some funky shifts as well!! I have been riding Yamaha XV920Rs (recently sold) and my SR500s. Both of these engines have BIG flywheels and gain or shed rpms at a much more leisurely rate than the VFR.

I have made a personal commitment to myself to keep riding the VFR until I get it right!! Yes, I know it's extreme, but I ain't scared!


Rex

 

Shifting is always fun on any new bike.
The VFR is one that benefits from quick shifts. I'm not talking about clutchless, just quick.
I get very smooth upshifts by 1)pre-loading the shifter 2)squeezing clutch to just barely disengage 3)letting the shifter pop into gear and 4) release the clutch.
I do this quickly, smoothly and without letting up on throttle (much).

Downshifts are pretty easy, but again are smoother the quicker you do them. 1)close throttle 2)squeeze clutch 3)click down 4)quick 1/2 turn of throttle and release clutch.

Practice making the steps fluid and you too will have smooth shifts:smokin:

 

I have tried about every solution that anyone suggested and it was the fuel pressure regulator from Turbocity that seems to have done the trick. however, i am not so sure it was too lean versus being too rich (i could be wrong though). after installing a set of Motad pipes, when running the bike the smell of unburnt fuel was extreme. then installing the revamped FPR, the exchaust smells better and milage has gone up. rumor has it that since Ducati has moved to O2 sensors, they are having the same problem.

 

shifting smooth and throttle jerkiness are two different things. shifting through the gears fast is great on the vfr no problams there nice and smooth all the way. I just find in first and second slow driving in heavy traffic(seems worse on a hot day) especially noticable for me anyways the throttle loses its feel or becomes jerkey no matter how lightly you twist the throttle i was finding it frustrating to reach behind to see if my kid had been jerked off the bike. since blocking the pair valve its been a lot better, still waiting for a hot day to really find out

 

I personally believe that PAIR does cause problems. It adds air into the exhaust track. More air means that the engine must work harder to expel it's exhaust. I don't believe that Pair effects other bikes as much because the Gen6 has more "environmentally friendly" equipment, like:
#1- Smaller headers to help increase velocity through the-
#2- Three way catalytic converter that acts as a "speed brake" for said, faster exiting exhaust gases.
Honestly, if you had to work harder at exhaling than you did inhaling, would you be as efficient? Engines need to breath and exhale with minimal effort, and this one can't. Then add in those oxygen sensors that don't let you add in all the fuel you want when you want it and throttle response is ugly. I am willing to bet it's going to get worse with newer emissions requirements in the future....:frown:

 

ditto

I concur, my learned freind,my 06 is as smooth as a babies arse (ass). Plus I have a K&N.

:tongue:

 

Just picked up my bike from the local shop. Had a good discussion with very reputable mechanic that used to work for our company for 15 years and now is with Loudoun Motorsports.

First off it seems as if these bikes are VERY individual in terms of engine management. Mine wasn't so bad, but he's seen some with bad surging low end etc..

Long and short all we did was synch the starter valves and return front sprocket back to stock mostly for speedo. I saw a noticeable improvement at 5k holding steady throttle. It didn't effect the VTec trans at all, but it wouldn't effect that anyway. He also said Pair valve MOD was BS not to do it, as it only effects expelled gasses after combustion and will NOT effect engine management characteristics period. I know the O2 sensors can dump air into system etc... but this guy is sharp and knows these bikes.

He also recommended against me personally doing the power commander as my bike runs good and I wouldn't pick up much in terms of power or smoothness in his opinion. This is a guy I trust even though its not my 15 year mechanic who doesn't do Honda anymore, but whom also agreed with Frank's assessments.

time to move on to RIDING! and Ventura pack system, and suspension and and and....:blah:

 

VaRollOn, interesting... a few days ago i was in talking to the owner of the local honda shop here, who pretty much gave me the same story you just posted. Outside of that, he said the only other thing would be a bad batch of ECUs. at the end of our conversation he muttered to bring my bike back in and he would talk to the mechanics.

 

Hey Placer,

Which map did you use? There are two maps on the PC site. One the '0' map and the other one references the 02 sensors and stock ex and stock filter. Which one did you load for your great results.

Thanks,

L2R

 

That's the spirit! We have too much time to nit pick these machines.

GO RIDE!:llama:

 

Hey L2R - I used the one that references 02 sensor removal and stock components. The "0" map actually tunes everying back to the stock settings, it's more used for trouble shooting so that you don't have to physically remove the PCIIIUSB. Let me know if you have trouble finding that map and I'll post it here. I'm at work currently, or I'd do so for ya now.

Hope that helps!

Kevin

 

Thanks Kevin....

I will get from the PC site... Hoping to have the same results you have.

Thanks again,

Steve

 

That's interesting. Is this an issue of Honda needing to refine the bike with each new model year? Are these issues more prominent on the earlier 6th Gen bikes than on the later ones? Anybody with an '05 or '06 experiencing the same problems?

I too have decided to wait on the Power Commander. I figure that I need to put some miles on my '07 and break it in first in order to determine if I have any of these issues. I hoping that Honda has the bike refined by now so that I won't have to do anything to it. I hope I'm not being too optimistic.