Does anybody else experience a brief loss of power when transitioning to VTEC?
It does not happen all the time, and does not seem to be related to which gear or what speed, but when going past the VTEC threshold I seem to sometimes have a very brief reduction in power before picking up sharply as the RPMs rise.
It is very jarring when it happens, and does not inspire confidence while riding.
That’s not right, mine feels like a 2 stroke hitting the pipe when the VTEC cuts in, no pause in acceleration
Agreed... No hesitation, just a sudden burst of power, though it can be a bit abrupt if it happens mid curve.
I'll never understand why they put vtec in a motorcycle, it's just a wrong idea from the start.
Thanks everybody, looks like it'll have to go into the shop. Any idea what could cause the hesitation?
EDIT: I'll check the oil level tonight to see if that is good, seems like it could cause the issue
Edited July 9, 2019 by 2015vfr4 hours ago, 2015vfrlooks like it'll have to go into the shop.
good luck finding a shop capable of fixing something complicated.
Is that straight from starting and riding off when engine is cold or mid run?
1 hour ago, finkIs that straight from starting and riding off when engine is cold or mid run?
Last time it happened I had been riding for over 10 minutes, in 5th gear accelerating on the freeway, at the transition, brief loss of power (bike jerks/hesitates for half a second) and then more power as the revs climb.
Whacking the throttle open in a high gear at relatively lower speeds will do this.
7 minutes ago, Egg on LeggsWhacking the throttle open in a high gear at relatively lower speeds will do this.
Throttle is being applied, but this does not happen when the throttle is first applied, it happens exactly when the vtec transition occurs, and only when the vtec transition occurs, so I'm fairly certain that it is tied to that system somehow
1 minute ago, 2015vfrThrottle is being applied, but this does not happen when the throttle is first applied, it happens exactly when the vtec transition occurs, and only when the vtec transition occurs, so I'm fairly certain that it is tied to that system somehow
OK, let me put it another way, if there was a system fault it would happen all the time. I can make my bike do it at will by being in the wrong gear.
Bear in mind I am new to this form and I have a 2015 VFR800 I just purchased (with only 3450 miles) trading in a 2017 CBR500R. When I was doing all my research on the 2014-15 VFR800's, all the official reviews that had dynos all noted a slight drop in HP just as the VTEC kicked in and then took off. You could see it right in the charts. Also, I purchased a Delkevic 8" slip-on exhaust and the dyno chart they provided showed the exact same, slight drop in HP before rocketing upward. The chart graphs were similar in shape regardless if it was a slip-on or a full exhaust. So based on all the reviews I read on this bike, I am going to say this is how Honda solved the "explosive" kick in complaints of the extra valves from the previous generation to make the transition smoother.
I am by no means an authority on this - just my two cents.
^^^^^. What he said. You can’t just go from two valve cross swirl to 4 valve without disrupting the induction pulses. Most Dyno charts show that dip in power at Vtec transition point.
Yup, mine does this, and most noticeably the first time after starting (even if the engine is warm by then).
I'm pretty sure I read more than one review before I bought, that said the same thing.
Overall the VTEC transition has been greatly improved on the 8gen when compared to the 6gen. Is there any chance you could test ride another 8gen as a comparison. Can honestly say I'm not experiencing what you've described on my own 8gen.
I checked the oil and level is right between the lines.
The power loss is severe enough to jerk me forward when it happens,
4 hours ago, 2015vfrI checked the oil and level is right between the lines.
The power loss is severe enough to jerk me forward when it happens,
That is definitely not right
My friend Makota San previous job was Chief Engineer Honda R&D who
invented Honda's VTEC... he calls VTEC "his baby" and recalls his boss
being super skeptical of the idea working at all...
Owners have their doubts too even naming VTEC Vacillating Torque Engine Compartment... granted it worked
on heavy cars but it's more of a unwanted bump in the powerband on a light bike...
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Makota San down on cannery row...
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Personally, I'm in the pro-VTEC camp. My only real criticism (6th gen experience specifically here...) is that it would be a more usable system if the VTEC transition point was on a curve... If I'm at 20% throttle, I probably don't need the extra valves until higher in the rev range. The one time I really don't like it is when I'm just easing into the throttle coming out of a curve and I suddenly pass the threshold and without warning I suddenly have more juice.
I forget who I swapped Mr.RC45 for their VTEC VFR north of Eureka Ca... I was so surprised to feel the hit in Honda's famous linear power ban that I thought I was bumped from behind... it was like I was back on the old cammy hit I4s...
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2015vfr, 7/10/2019 at 1:51 PMLast time it happened I had been riding for over 10 minutes, in 5th gear accelerating on the freeway, at the transition, brief loss of power (bike jerks/hesitates for half a second) and then more power as the revs climb.
I'm willing to bet you're not giving enough throttle input. The less time your rev counter spends in the transition zone, the smoother it becomes. Change your shift points accordingly.
No problem here, ever on two VTEC VFR's. The argument that VTEC doesn't belong on bikes has gone on at least 8 million times now. It just doesn't matter any longer....
Adapt, adjust, and overcome.
3 hours ago, SEBSPEEDI'm willing to bet you're not giving enough throttle input. The less time your rev counter spends in the transition zone, the smoother it becomes. Change your shift points accordingly.
My thought exactly, same with quickshifters
2 hours ago, BentNo problem here, ever on two VTEC VFR's. The argument that VTEC doesn't belong on bikes has gone on at least 8 million times now. It just doesn't matter any longer....
Adapt, adjust, and overcome.
Well said.
Saoirse, 7/10/2019 at 12:32 AMI'll never understand why they put vtec in a motorcycle, it's just a wrong idea from the start.
Agreed, I just hear an increase in the noise and not much more. It makes the valve adjustment more complicated. I don't really care I like this bike anyway. 😊
BusyLittleShop, 7/12/2019 at 11:09 PMI was so surprised to feel the hit in Honda's famous linear power
To the op, sorry I haven't any suggestion other than to ensure that all is well with the bike. The transition on my '09 varies depending on gear, and on how quickly the revs are climbing. My one, short ride on a '14 didn't offer any insight into its VTec behaviour. And frankly, I was more interested in its off-on throttle response, and how that compared with mine.
The VTec is all sizzle and no steak, and is a primitive system compared to its implementation on Honda's cars. The '98-'01 VFR800 have the same performance without the annoying (at times) hiccup in the middle of the power band. And without the equally annoying twitchy throttle that also plagues 6th gen VFRs
It is clear from Honda's 2002 VFR press blurb that the goal was lower fuel consumption and lower noise, and VTec was their chosen method.
I like my '09 VFR a lot, but despite VTec and not because of it. Fwiw, I've racked up 80,000 km on it, and another 120,000 km on my 5th gens.
I gather owners either didn't want VTEC or since the VFR is other wise perfect all a rounder they just put up with it... not enough owners say they love VTEC for Honda to justify lower fuel consumption...
I just wish they would have figured out a way to do it with gear drive cams!
VTEC and gear drive are not mutually exclusive; the cams don't care how they are being spun. My take on the loss of the gear drives is it made the engine cheaper to build and reduced engine noise.
Absolutely... They could have, and I would be willing to bet that money made the decision, not engine noise. Still, in the end, they didn't...
As long as we're way off the OP's topic, did I hear about someone building a hybrid gear driven VTEC from two VFR engines, or did I imagine that?
Terry, 7/29/2019 at 6:16 PMthe cams don't care how they are being spun.
HRC cams cares...
Granted most street 4 strokes use a simple chain to turn the cams whereas Honda's
race bred V4s employ gear-driven cams for the simple fact gears provide the most
accurate and reliable form of cam operation regardless of RPM...
Every time I hear that cam gear whine I know good things are about to happen...
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Marvelicious, 7/30/2019 at 5:46 AMAbsolutely... They could have, and I would be willing to bet that money made the decision, not engine noise. Still, in the end, they didn't...
As long as we're way off the OP's topic, did I hear about someone building a hybrid gear driven VTEC from two VFR engines, or did I imagine that?
Mark Harris on the UK VFR forum put a pre-VTEC 800Fi engine into his 6th gen a few years ago, still has the bike.
2 hours ago, fatshoutyblokeMark Harris on the UK VFR forum put a pre-VTEC 800Fi engine into his 6th gen a few years ago, still has the bike.
Not what I meant... I think there are a few of those that have been done. I'm talking about driving a VTEC head with gears. Much more difficult and I think I probably imagined it.
squirrelman, 7/9/2019 at 8:08 PMgood luck finding a shop capable of fixing something complicated.
Exactly. This is the problem with today's high tech motors, the mechanics are low wage.
Hi - did you ever resolve this ? Mine has done it since new - I get a strong judder/stutter/jerk as the vtec kicks in. Worse when wet - not clever if it kicks in on a wet bend or wet overtake. Been back to the Honda shop several times and they can't find a problem. Thanks.
DanVFR2014, 9/15/2019 at 2:24 PMHi - did you ever resolve this ? Mine has done it since new - I get a strong judder/stutter/jerk as the vtec kicks in. Worse when wet - not clever if it kicks in on a wet bend or wet overtake. Been back to the Honda shop several times and they can't find a problem. Thanks.
No, just happened again today. In 4th gear, moderately heavy on the gas after a freeway transition, jerked me forward into the bars. Unpleasant and does not inspire confidence in the bike.
I have not taken it into the dealer yet.
2 hours ago, 2015vfrNo, just happened again today. In 4th gear, moderately heavy on the gas after a freeway transition, jerked me forward into the bars. Unpleasant and does not inspire confidence in the bike.
I have not taken it into the dealer yet.
That just should not happen. I wonder wether you have an issue with the VLC solenoid (Valve Lift Control solenoid), could it be internally sluggish or, the one wire electrical connector for it gone high resistance? As it is only a one wire device it requires good Ground bonding to the battery negative!
Assume you are running correct viscosity oil? (Just a long shot!)
During 4 valve transition the ECM will very quickly adjust timing and fuelling as the VTEC valves slip into operation, would imagine the timing of the valve engagement and synching that to what the ECM is doing with fuelling and ignition to be critical for a smooth transition.
Seeing its out of warranty and If it was my bike I'd certainly have a good look at the VLC Solenoid one wire connector and try driving the valve independenty with a 12v source listening to the valve click every time voltage is applied (as per service manual)
Other than that, I'd probably head off to a reputable Honda dealership, one that would be prepared to consult with Honda Japan if the dealership doesn't have the answer.
Not sure if this helps but good luck with getting it sorted.
My current 2014 8gen most definelty has the best overall VTEC transition than my three previous 6gens.
All this talk of the VTEC taking you by surprise WTF ....transition is 6,700, it doesn’t move around
3 hours ago, ThumbsAll this talk of the VTEC taking you by surprise WTF ....transition is 6,700, it doesn’t move around
I often look at things other than my tach.
2015vfr, 19 September 2019 at 3:57 PMNo, just happened again today. In 4th gear, moderately heavy on the gas after a freeway transition, jerked me forward into the bars. Unpleasant and does not inspire confidence in the bike.
I have not taken it into the dealer yet.
Is there any chance you could get to compare your bike to another 8gen. Perhaps there might be a VFRD member near you that may be able to help you out, shouldn't matter wether it's a 2014 model onwards. Think this is the only way to conclusively know if you have an issue, although, based on what you say, it doesn't seem right.
Also DanVFR2014's comments "I get a strong judder/stutter/jerk as the vtec kicks in. Worse when wet". Think he also needs to compare his to another bike, especially as he states the "Honda shop" can't find a problem!
Another more scientific option may be to have your bike Dyno checked and present any findings to the Honda dealership.
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