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Discussion Starter #1
Anyone who owns a Honda VFR 800 VTEC really should read the following. I have been dealing with this saga for a year and it finally appears the answer is at hand. The starter valves are not synced properly at either the factory or the dealer, plus the service manual is very misleading!

The improperly synced starter valves cause the engine to be much harder to control under some circumstances at smaller throttle openings.

I would like this stickied please as it may be some time before all VFR VTEC owners get the chance to review it.

http://www.bikersoracle.com/vfr/forum/showthread.php?t=44763&page=1&pp=15
 

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Chumly has asked for this to be stickied for a while. I'll hold it stickied as long as some other VFR folks come forward and check in. Otherwise I'll leave it here for a month and then let it drop.

I suspect most VFR owners are also members of the VFR boards and the knowledge of this will get around pretty quick.
 

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TeeTee said:
I suspect most VFR owners are also members of the VFR boards and the knowledge of this will get around pretty quick.
And of course, some of us don't have the problem either...
 

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Discussion Starter #4
Hi Tony,
I’m glad you don’t experience any problems and hope that none appear as time goes by. For many, the gestalt of riding conditions, such as the rider's style & roads dictate how noticeable these issues are.

I notice it a lot in part because I am often riding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roads.
 

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Chumly said:
Hi Tony,
I’m glad you don’t experience any problems and hope that none appear as time goes by. For many, the gestalt of riding conditions, such as the rider's style & roads dictate how noticeable these issues are.

I notice it a lot in part because I am often riding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roads.
I am up to 22,000 kms with no problems at all. Riding ranging from quick runs up to the Okanagan and beyond, 7 or 8 Duffey Lake loops and some very enthusiastic banzai runs through the twisties - all without any hiccups or hesitations and an always smooth and pleasing VTEC transition. I may be one of the lucky ones but my bike is stock except for my only mod - new Remus pipes ( :thumbup ), but the bike has been absolutely faultless with only the required basic maintenance for oil changes, new tires etc.
 

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Discussion Starter #6 (Edited)
Hi Tony,

Part of the problem with positive assessments such as yours (and negative assessments such as mine) is that in isolation they are one person, subjective and somewhat arbitrary.

We would need to place our two bikes back to back in identical circumstances that exacerbate potential negative tenancies to see whether your bike performs differently than mine, at least in terms of our abilities and experience.

That is not to suggest that I would presume that your bike performs the same as mine and you don’t notice it, but it does potentially eliminate a certain degree of subjectivity.

The other needed step in comparison analysis would be to compare starter valve sync differences and other measurable variables. Only then we would have a basis of comparison of both a subjective and objective nature.

This is being done as we speak in the UK by "Wiz", his cohorts, and Honda UK. It might be interesting to parallel their efforts here.

A classic example of the arbitrary element of what I am referring to is your reference to “pleasing VTEC transition”. I consider any noticeable transition due to the VTEC engagement to be distracting and unpleasing.

Another point of potential subjectivity is as mentioned the gestalt of riding conditions. The "fueling problems" experienced are not most prevalent under the circumstances you refer to “quick runs up to the Okanagan and beyond, 7 or 8 Duffey Lake loops and some very enthusiastic banzai runs through the twisties” but are most prevalent under the circumstances I refer to “riding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roads”. Two different environs, two different riding styles, two different sets of expectations.

The starter valve sync has no effect on VTEC engagement by the way. Nor does the starter valve sync likely have an effect on the lean-out part-throttle cruise surge problem. Given that you are running a non-stock exhaust does somewhat complicate a direct comparison.
 

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Chumly said:
A classic example of the arbitrary element of what I am referring to is your reference to “pleasing VTEC transition”. I consider any noticeable transition due to the VTEC engagement to be distracting and unpleasing.
By pleasing, I mean smooth and strong - with the VTEC transition noticed by strong and smooth acceleration, and of course the change in exhaust note. There is no noticeable transition (ie, never any hesitation or abruptness or flat spot) and never has been, except for the smooth acceleration as the VTEC does its thing. I have been riding for 25 years +/-, and I have ridden plenty of crap bikes that sputter and misfire etc - the VFR has been faultless (although I would like an extra 20 or 30 hp!).
 

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Discussion Starter #8
Hi Tony,
You may have misunderstood some of my points. The VTEC transition is not really at issue here, I referred to it to help illuminate the subjective versus objective nature of the VFR experience and how one might reduce the objective element. I am *not* arguing the merits or lack thereof of the VTEC transition.
 

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These same discussions have occurred with the previous '00 model VFR. With them it was the dynamics related to the O2 sensor. They all boiled down to the fact that the VFR, for all its greatness, is not a track bike.

What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike. Those who live on their VFRs, like I did up until this year, have learned either consciously or unconsciously to minimize the unique nature of the VFR's throttle response. For them it has become a predictable and reliable part of the bike and is no longer noticed. Riders that alternate between bikes do not develop this as easily and I think that this is were the more difficult reviews of are coming from.

If I had a v-tec bike*, I would ride it for a month or two and leave my other bikes parked. If one constantly jumps between bikes, the differences only become sharper.

-Sandworm
*I would never purchase the current v-tec model, but that has more to do with my tastes in electrical systems than the v-tecs throttle response.
 

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Sandworm said:
What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike. Those who live on their VFRs, like I did up until this year, have learned either consciously or unconsciously to minimize the unique nature of the VFR's throttle response. For them it has become a predictable and reliable part of the bike and is no longer noticed. Riders that alternate between bikes do not develop this as easily and I think that this is were the more difficult reviews of are coming from.

-Sandworm

Good point. I rode an RC 51 before the VFR, and the throttle response on the RC seemed a little 'sharper' and obviously the power was more linear, but when I got on the VFR, the throttle response did not seem too different or out of place. I have ridden other bikes where the throttle response is much different from the throttle of the RC and VFR. Only one bike now, so no direct comparisons.
 

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Discussion Starter #11
Sandworm said:
What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike.
Interesting Master Worms, but in this specific case it strongly appears that the SV’s are quite often not well synced and hence exacerbate part throttle tractability, all other perspectives aside.
 

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I red that article about a month ago , very interesting . This is my first fuel injected bike so I'm not really sure how it's suppose to respond at steady slow speed but I think that it does act kinda weird. I would really like to compare to another VFR,
 

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Discussion Starter #15 (Edited)
rubberhead said:
Can someone post URLs to these boards please?
The really good news is that a Starter Valve Sync solves some /most/all of the issues people complain about.

These threads do ramble and go off on many tangents. The essential point now is that the Starter Valves are rarely in sync, the dealers don’t do it so you need to go with a Morgan Carbtune. Also there is an outstanding issue in that the Shop Manual is very likely to be incorrect/incomplete.

I support “Wiz” and all his posts with the possible exception of the interpretation of the shop manual's Starter Valves settings. I would want Honda Japan to comment on the Shop Manual, but they have not.

The O2 Sensor Swap has turned out to be a red herring from the perspective of Honda Japan. They officially have said that none of bikes are wired around the wrong way. That does not mean that O2 Sensor Swap does not have an effect, it can force the EFI into open loop operation.

Perhaps the best for info on the fueling problems (home of "Wiz")
http://www.bikersoracle.com/vfr/forum/showthread.php?t=44763

Perhaps the second best for info on the fueling problems
http://www.vfrdiscussion.com/forum/index.php?showtopic=10032
 

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Discussion Starter #16
nutcracker said:
I red that article about a month ago , very interesting . This is my first fuel injected bike so I'm not really sure how it's suppose to respond at steady slow speed but I think that it does act kinda weird. I would really like to compare to another VFR,
PM me and we'll see :)
 

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Discussion Starter #17
I had a nice chat with Jeff at Honda Canada (I asked the same question this time last year). I was told that the Honda Canada Technician’s official position is that they recognize that there are certain "characteristics" that the motor may have, such as the VTEC engagement, off idle sharpness, and steady throttle surge but that these "characteristics" are "normal" for the bike, and they have no plans at this time to do anything about, but that the Honda Canada Technician’s have logged my concerns and that they have received other logged input from other owners with similar concerns.

Jeff at Honda Canada said he very much doubted that there is anything wrong with any of the ECU’s. He went on to say much the same as last year; that Honda is meeting very tight future emission standards, while producing very high performance engines, and that it is a difficult balancing act.

Jeff did say that the use of premium gas in Canada has an additive that can coat the 02 sensors and make them lazy or ineffective, and that may be a cause for some problems. I told him that the 02 sensors only contribute in the limited conditions of steady state closed loop cruising, so as to lean out the mixture, and that ineffective 02 sensors would not affect performance under constantly changing throttle inputs as the EFI does not go into closed loop unless it is steady state throttle.

If you wish to communicate with Jeff to log your concerns he can be reached:
Honda Auto, M/C, P/E & Marine Customer Relations
Jeff (3393) 1 888 946 6329
 

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Discussion Starter #19 (Edited)
You can read my research into this subject and what I did here -:

http://www.vfrdiscussion.com/forum/index.php?showtopic=30237
I have a PC III and O2 elims and did a really precise SV sync as well as remove all slack from the throttle cables. My bike is better but does not equal the linear throttle of many other bikes.

From what I can tell you are saying that removing PAIR will have no effect if O2 elims are in place. Perhaps that’s why I never notified any improvement when I disabled PAIR, so I left PAIR enabled but…….are you aware that the O2 sensors do absolutely nothing most of the time, and only come into effect during closed loop, steady state, steady throttle cruising operation and not at other times? The O2 sensors on the VTEC do not act as they do in a modern auto engine where they are relied on much more often. Also the VFR ECU is not a “learning” ECU.

I get the impression from your posts on VFRD that you might believe the O2 sensors are enabled (i.e. closed loop) much more often than is the case (as is the case with modern auto engines.
 
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I have a PC III and O2 elims and did a really precise SV sync as well as remove all slack from the throttle cables. My bike is better but does not equal the linear throttle of many other bikes.

From what I can tell you are saying that removing PAIR will have no effect if O2 elims are in place. Perhaps that’s why I never notified any improvement when I disabled PAIR, so I left PAIR enabled but…….are you aware that the O2 sensors do absolutely nothing most of the time, and only come into effect during closed loop, steady state, steady throttle cruising operation and not at other times? The O2 sensors on the VTEC do not act as they do in a modern auto engine where they are relied on much more often. Also the VFR ECU is not a “learning” ECU.

I get the impression from your posts on VFRD that you might believe the O2 sensors are enabled (i.e. closed loop) much more often than is the case (as is the case with modern auto engines.

First let me say Hi and thanks for the reply.
A little bit about myself, I have been a tech, working for BMW (cars) for the past 35 years. I have owned this 05 VFR for just over a year This year I got to thinking that I should be able to get the thing to be a bit more smooth on take off than it is. It is awesome on the highway etc but it really is hard work around town. Anyway this is why I am experimenting and asking questions.
I was not aware that the o2 sensors only work in closed loop at certain times.
I have never heard of this on any ECU cat system that I have come across before as for the cat to function properly the engine has to run in closed loop all the time. I will monitor the o2 sensors while riding to see what happens!
Today I got out and tried the bike for a good long ride with the pair valve blocked. The response from closed throttle at slow speeds is a lot better however the throttle is still jerky at say 3000 in second when riding along on a steady throttle (if that makes sense)
Also I thought that on deceleration without the pair valve that the mixture would be rich in the cat and I verified that as I get a sulphur smell when going down hill with throttle closed.
From this you can say that if the pair valve is to be disabled for any length
of time the cat would have to be removed. If not I can't see it lasting too long. Honda it looks like add additional air from the pair system to pass emisions on deceleration. To me right now it looks like we would have to remove the cat, add the resistors, remove the pair, sync the starter valves and remap using a pc III. It looks like you are almost at that point anyway:laughing
I am going to install a lot of test equipment and try to see whats happening?
I don't see why it's the way it is, alright the vstrom I had was not as highly tuned, the Ducati ST3 is a v twin, but the speed triple is highly tuned and passes emisions AND the mapping is spot on!
 
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