VTEC- can you feel it

Oops, forgot the alternator question. yes I have, some
time ago. Other than the dealer pulling a stoppie on
my bike and smashing the license plate, all ok. This
situation was only a problem if you run the bike at
idle with brites on and cooling fan going and would
cause dead battery as alt could not keep up with the
loading/charge to battery. I don't ride with brites except
when needed at nite as bike;s low beams are plenty brite.

Also, on the VTEC activation at 6800 rpm, it will not go
to 4 valve unless coolant temp is over 149 F, this may
explain why sometimes you don't seem to feel it on
a cold bike.

 

My late 02 is nearly broken in and I love it, 7000rpm and wham hang on! The step change reminds me of my onced owned 1973 Kawasaki S1A 250 triple. ;D. I suspect a K&N will emphasise the bark a little more and help the buzz as ripping through the twisties! Smooth throttle is need if cranked over as you transition else it kicks a bit.

 

I have a 03 VTEC, and there are a few annoyances, but it really is the best bike you can buy for the money. I too seem to have a flat spot around 4500 RPM while on a constant throttle. I don't notice it while winding on the power. I does take some time to get to "know" this engine to be able to ride smoothly. A change in gearing is required, as you need to slip the clutch a little too much to make a quick launch. I'm starting to like the audible change of 2 valve to 4 valve mode, as it lets me know where exactly I am in the rev band without having to take my eyes off the road, and I know how much power I'll have when I crank the throttle. It does't help in the wheelie dept. though. Best wheelies are done above 8000 RPM where power delivery is more linear.

 

I own a 2003. Can't add anything to this conversation. I love the bike, what can I say!

Like the rest of you I feel the Vtec kick in! Its not overwhelming but noticeable @ 7000rpm. It sounds great when the extra valves open. I'm curious if, in time, companies will make a product that removes the Vtec and keeps the 4 valves open at all times!? I wonder?.

Great bike!

 

Howdy Diesel Drive,

I've had my '02 VFR since last September, and yes the transition from 2 valves to 4 valves is noticable. If you've ever driven a car with a turbo or ridden a 2-stroke bike when the power rolls on, then this is much the same sensation as the VTEC valves on the VFR.

I have not made any modifications yet to my bike, and from what I have read and personally experienced this VFR would greatly benefit from a Power Commander.

The first thing that I have noticed is that there is somewhat of a flat spot between 4 and 5 thousand rpm. Holding the throttle constant once the engine is warm you can feel a bit of hesitation, and in some worse case that I have read about (but has not personally happened to me) is the engine feels briefly starved of fuel. What what I've read getting the PC III with the oxygen sensor eliminators should smooth this out.

The other interesting thing about this bike is the transition between 2 and 4 valves per pot. If the bike is on the stand and I rev it up I can't hear it, but if it's travelling I can definiately feel the other valves kick in. Having driven turbos this is something I like, however, one thing I don't like about it is the electronic fuel injection doesn't seem to dialed in perfectly at 7 grand.

What happens for me if I am not opening the throttle wide but slowly increasing the the engine revs, it will smoothly go up to 7K at which point the other two valves open, at which point the fuel air mixture becomes too lean, at which time the engine is getting less juice, so falls below 7K RPM. As soon as this happens the second pair of valves close, at which point the fuel air mixture richens up, and then the engine gets some more juice, and starts to go above 7K.

If you see what I am describing, there is a certian throttle amount at certian RPMs where this bike will surge and slack in and surge and slack. It is not dangerous but it is noticable and most so at low RPM but will do it in any gear. My turbo car does not do this sort of thing. The boost and fuel air mix will be considered by the ECU and the engine will act right at any rev. What I am really hoping is if I get the Power Commander and maybe open the airbox snorkle this transition can be smoothed out. If this doesn't work I should be able to go to the dyno shop and get them to adjust my fuel injection map such at at 7100 RPM the mixture is just a tad more rich.

I'd really be interested in bypassing that solenoid switch and putting a toggle on my dash board that will let me select VTEC. I would like to be able to turn it on for highway driving and only use 2 valves, but have all 4 valves working if I want to have a nice smooth powerband.

Now, let me say that except for these eccentric fuel injection things, this is an amazing motorcycle, definiately the best one I've ever written. I've ridden dirtbikes, cruisers, and older sportbikes. I have never been on a finer ride, or a better compromise between sport and tour. No Joe Cephalopod on a 600 sport ride can lose me, I'm on them and have 100 cubes to counter my extra weight. I don't feel bad being passed by a Busa or ZZR1200, because I know I'll be making half the fuel stops they will be. It's got a couple of bugs, but otherwise an amazing vehicle. In the interim, I've learned to deal with the transition. I don't think the hit is a problem for sport riding, unless your in a deep lean on a wet road, but this is true for punching the throttle on any sport maching in bad weather. If anything my VFR loves the wet.

So what I'm saying is that I love my VFR.

 

Thanks to all who replied. I started this thread when I got the 02 viffer and first heard and felt this transistion. having gotten off a 98 viffer I found this new gizmo to be nothing more than overengineering at the worst. Some have likened the transistion to that of a turbo coming on or that of a 2 stroke powerband. I don't agree at all. I have 2 turbocharged vehicles and a new CR 250 and it is not the same (to me). What I feel is an abrupt change in the sound and feel. It really sounds and feels like the engine miises a beat. I liked the 98 much better!

Anyway to end it all here goes. I did not really use the touring attributes of the viffer to it's potential anyway so I thought I would try something more on the sporty side and ditched the viffer for an 03 R6, that's right, a Yamaha. I have been a loyal honda rider for years but am developing the opinion that Honda makes what they want people to buy rather than making bikes that people want to buy (I have a 520 EXC KTM that is a perfect example of this, Honda refuses to make a comparable bike, sure they make XR's and CRF's but they do not offer a world class racing woods bike, period. You can build one yourself from a Honda but they do not, by the time they do come out with one later this year Yamaha and KTM will have already sold thousands). Sorry to ramble, but I am disappointed in Honda (I still own the CR and like it very much for it's intended use).

Most of you won't care about this paragraph but here it is. True that the R6 does compromise comfort for performance, but Oh what a feeling that can be had from a 120 Hp in a 357 pound machine. The vibration is actually less than the viffer and the power is at a higher rpm (normal for a 600), but light weight cannot be matched in the area of turning and suspension capabilities by a heavy bike. There have been several comments that the viffer can hold it's own against sportbikes and that may be true. It can not , however, hold the light for a supersport to run by in the area of handling/turning/suspension. I will never use the R6's engine at anyway near it's potential, but this bike inspires confidence in the area of turning and suspension that you would not believe unless you would try one out. It makes the VFR handling seem like a sled (sorry to be so blunt). For you guys (and gals) that tour, you would not like the low bars. The footpeg/seating position is just as comfortable as the VFR though (a good deal for just a little over 7 grand for a brand new one too).

Again, sorry to be so long winded and thanks again for all of the replies to my original post.

 

WOW. I guess that really did end this thread.

Sorry if I offended anyone.

DieselDrive

 

The V-tec got way smoother with me after I fitted my bike with an after market exhaust. It just breathes better I guess

 

I own a Kawasaki ZRX1200r but have a friend with an 02 VFR800, so I'm asking this question on his behalf.
I've ridden the VFR a couple of times and it seems weak and sluggish at low to mid range, then at @ 7k rpms it buzzes loudly and picks up alittle bit, but still pretty weak.
I was wondering if there could be something wrong with his bike? He bought it new and has been real gentle with it. I have not mentioned any of this to him as I don't want to worry him, but if it is a problem that needs fixing then it should be fixed.
Having said all that I have to give the VFR kudos for style and handling. it has to be one of the best looking bikes on the road.
Please let me know if you can help.
Thanks,
ZRX12

 

I have a 2002 VFR, I owned a ZRX 1100 and I have ridden a ZRX1200. The VFR doesn't have near the performance of the ZRX1200. I doubt that there is any thing wrong with your friends bike. The VFR is a great overall bike. However, it doesn't have the grunt of a 1 liter plus in-line 4.

 

Hy guys,

Here is my .02. Give me my four valves per cylinder all the time..now!! Please!! The air/fuel mixture at the low RPM's (all for the sake of emmisions and fuel economy) seems to be mapped wrong. Was wondering how much of a hurt I would be putting on the secondary valve train running them full time. Other than the low rev crap my '03 rocks!

Greg

 

I admit the power at low rev. may seem weak compare to other bikes, but the VTEC challenge feel more like a fuel saver than a power feature and that's the way it is.
also the bike is heavy which is great for touring, but slower to accelerate...

the 02 still give hell of a run compare to my car

 

Food for thought.

Using a relay and a switch to manually open the V-TEC solenoid will not work. The solenoid only allows the oil pressure to activate the V-TEC. At low engine speeds, there isn't enough pressure to hold all the valves open, so you may end up with a few open and a few closed, or some partially engaged (which would beat the crap out of the system). Worse yet, you could actually be diverting much needed oil pressure from other parts of the engine at low speed, causing starvation.

Disabling the V-TEC will be a little more complex. You will have to remove the V-TEC valve bucket and all it's internal parts, then replace them each with a non-V-TEC bucket and shims, like the other valve has. Next, disable the solenoid to prevent a loss of oil pressure above 6800 RPM.

I haven't done this, but my engineering experience tells me that this is the way to go, assuming that the parts from the non-V-TEC valve will fit on the V-TEC valve.

You don't want a switch to allow a manual choice of when to run in 2-valve or 4-valve operation. If you do, which way would you map the computer? You can't load both maps for the same RPM range.

Ideally, the best solution for the V-TEC will be to simply allow it to open at a lower RPM setting, like right above the flat spot. 5,800 RPM or so. The reason you get a power kick at 6800 RPM is because the engine is slightly starved just below that range (like Yamaha did with the V-Max). If you tune out the V-TEC hit, the bike will BE faster but FEEL slower.

 

has anyone tried to disconnect the vtech?

 

has anyone tried disconnecting the vtech by simply removing the wire that goes to the solinoid valve?

 

Hi Mate. Question on 7,ooo kick in for V Tec engine.
Purchased bike few months ago.
First time it kidded in I was not prepared for kick from engine,however after few months riding I have to say
if you know your revs(sound etc) you will have no problem with noise,engine,traction etc.
Just ride and enjoy.
Andy Bray

 

Have owned an '02 and now an '03 (I must like 'em them ;D ), first one was stolen but had all the problems that the 1st poster complains of, fitted PCIII, O2 elims and a K&N without really resolving the problem. I suggest that those that suffer from the kick at 7000rpm get their starter valves synchronised by someone who knows what they're doing, reportedly it has a marked effect, only found out about this after the '02 was lifted. My replacement '03 is totally sweet, I can't fault it.

 

You can feel it alright. I just bought an 04 VFR 3 days ago. Traded in my 03 Road Star Warrior. Talk about a kick in the ass torque. Anyway, I love the the VTEC. Its not annoying and has a seamless transition. You really have to get on the throttle and whin it through 7k in 2nd and 3rd to feel the punch. In 1st gear ints not very noticable, just really loud.

A quick question to anyone out there. Any good websites to find VFR accesories. Example, tank guards,led lights, k&N filters etc. ;D

 

Not real sure what everyone is complaining about with the change from 2 valves to 4. I love it!!! Not only am i not worried about traction loss, but the feel and sound are incredible.... ride a 2-stroke dirt-bike for a couple months and tell me you don't have a deeper appreciation for the surge. I ride with very fast guys on very fast bikes... and have no problem keeping up and ahead. The bike shows no weaknesses aside from the fact that the pegs are a little close to the ground as i've ground the feelers off of both of them. This bike can be manhandled by the right size guy (me..5'10" 220lbs) or it can be given the lead rope and left to do the work for you...which is how i normally ride it. I crouch over the tank and plant my ass and just lean with the bike. i've pulled the vtec on in 4th and 5th through the twisties and have never experienced a raised hair. This bike is awesome...and you know what?....i can ride it longer and harder than my buddies with gixxer 1000's, 750's and a couple rc51's. I also have seen no cosmetic issues with the bike. Mine is an 02 with low mileage but i am not worried. My suggestion to those with chipping and pitting??......leave a little more room between yourself and the vehicle in front of you. The only thing chipping and pitting is what is being thrown into the bike by other vehicles. I love my VFR...for all of you who have one...enjoy it and keep the shiny side up.