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-   -   Vtec fuelling/throttle control problem - a new hope. (http://www.bikersoracle.com/vfr/forum/showthread.php?t=44763)

kaldek 10-05-2010 12:28

Well folks, a $5 inline fuel filter between my intakes and the MAP sensor has removed nearly all vacuum flutter.

Tomorrow I will be testing how this affects throttle response. Wish me luck!!

unfazed 10-05-2010 20:37

I have a 04 vtec with 11k miles purchased in Feb and after reading this thread and others I am wondering if I have is a bogus machine? Carefully searching for these various faults listed here I can't find any! I did 300 odd miles yesterday and I find the power delivery from 4k upwards very smooth apart from the rather indiscrete arrival of the vtec. There is certainly no snatch on take up. The only point is that below 4k the one gets the impression of the bike 'lumping' along somewhat but this is an identical characteristic to a VTR I previously owned so I put that down to the V cylinder arrangement. I am not a hardened VFR fan and also have an 08 FZ1 Fazer. So if my vtec is Ok it suggests others that are not my have individual curable problems and is hardly a question of luck as someone once suggested. I think this is a great bike. (I hope this is not tempting fate:))

kaldek 10-05-2010 23:21

Quote:

Originally Posted by unfazed (Post 1272834)
I have a 04 vtec with 11k miles purchased in Feb and after reading this thread and others I am wondering if I have is a bogus machine? Carefully searching for these various faults listed here I can't find any! I did 300 odd miles yesterday and I find the power delivery from 4k upwards very smooth apart from the rather indiscrete arrival of the vtec. There is certainly no snatch on take up. The only point is that below 4k the one gets the impression of the bike 'lumping' along somewhat but this is an identical characteristic to a VTR I previously owned so I put that down to the V cylinder arrangement. I am not a hardened VFR fan and also have an 08 FZ1 Fazer. So if my vtec is Ok it suggests others that are not my have individual curable problems and is hardly a question of luck as someone once suggested. I think this is a great bike. (I hope this is not tempting fate:))

The bike is extremely sensitive to starter valve sync. The thread I have over at VFRD is me trying to find a way to remove that sensitivity so that more bikes have better throttle response, particularly those that seem almost impossible to tune out the problem.

greenman2 14-05-2010 19:49

Hi Unfazed, when I bought my VFR I was down to a shortlist of an FZ1 or VFR. How would you compare the two machines. I like the VFR and admire its many qualities but somehow its not a bike I itch to ride, it just does the job very well.

unfazed 15-05-2010 07:51

I find the FZ1 and the VFR very different bikes indeed. Despite various reviews to the contrary I find the FZ1 very heavy on fuel and in my case not much more than 30 mpg. I bought the VFR as a work commuter bike and so long as the vtec is not 'in' is much less thirsty.
The second comparison I would make is in the performance. There is no comparison here as I find the FZ1 with its 20V R1 150bhp engine produces manic acceleration particularly after 8k revs. It is, of course, to be expected with around 50% more power. It's a good job I am too big for an R1!! Where the VFR has the advantage is that it has much more torque making the bike much more controllable (less braking) particularly at lower revs. ( It is all relative, though, the VFR having little torque compared with a CB1300 I owned earlier!)
My final comparison is a bit of a paradox. Although the VFR is branded as a (sports) tourer it is less suitable for long distance than the FZ1. After 250 miles my wrists, shoulders and back are near the limit whereas on the FZ1 its upright riding position is much more comfortable. I do have Yamaha's after market 'comfort' seat.
So that is my personal mini review:)

greenman2 23-05-2010 17:44

Thanks Unfazed. I'm surprised at the poor fuel consumption on the FZ1, though not the performance! Also surprised at the comfort. I find the VFR comfortable enough, but not armchair-like. I had a Tiger and a Multistrada and both were better then the VFR.

I get between 45 & 47MPG from the VFR on a regular 85m commute, mostly M4 and dual carriageway at 85-90 and think this is OK, though my 749 will do the same going 5-10 mph faster. I also bought the VFR as a commuter and find the torquey engine and excellent mirrors make it well suited, though it does need to be above 4500 revs to go at all well. I'm less happy with the handling, it just feels it's weight for me, not that well balanced at low speed.

unfazed 24-05-2010 19:41

Interesting point about 'feels its weight'. After just 2 weeks I dropped it the first time in many years of riding I had let a bike fall over when stationary. Fortunately it was in the garage where I had a strip of wood on the floor and it was more of an unresistable lowering. So no damage. But being used to heavier bikes couldn't understand why. Doesn't seem to be much leeway from the vertical position before gravity takes over. Perhaps its just me!

Rawhide 30-05-2010 01:17

gotta throw something into the mix here.
 
Are you aware that when you open the throttle you create a temporary lean condition. The oxygen sensor then adjusts the mix to accommdate this. When you shut it back it might go rich (not sure here to be honest) Anyway the condition can confuse the ecu because it can take the unit outside of its map. This was always the problem with Narrow Band sensors. And the reason why wide band sensors are now being used. I went through all of this with my golf, but the Honda CRX also makes use of WB sensors, some even have heating elements in. Does anyone know if the vfr sensors are narrow or wide. There's been alot written about this on the net, nernst cells and all sorts. What I'm wondering is, what conclusions can we draw from the varied throttle test?

Also, I've got this problem on my FiX. It may not be as bad as VTEC but it is still a pain. Has anyone got any suggestions? Apparently the carbs on the 750 were alot smoother.

Rawhide 30-05-2010 01:21

Quote:

Originally Posted by crazygreyguy (Post 1221761)
I tried everything with my 03 vtec - balancing SV's 16000 mile service, using expensive petrol etc and using a really good Honda dealer. Finally bit the bullet and dumped the Cat replacing with a motad collecter box. Problem solved! Runs as it should, can hold a steady throttle at any time in any gear at any rev range! Does sound a wee bit different, not noisy but how a v4 should sound. Can now use cheap fuel!! Expensive to have replaced though. Could be done by a competent home mechanic but remember the word competent:)

see what i'm getting at in the post above?

Ed_Case 30-05-2010 21:50

Quote:

Originally Posted by crazygreyguy (Post 1221761)
I tried everything with my 03 vtec - balancing SV's 16000 mile service, using expensive petrol etc and using a really good Honda dealer. Finally bit the bullet and dumped the Cat replacing with a motad collecter box. Problem solved! Runs as it should, can hold a steady throttle at any time in any gear at any rev range! Does sound a wee bit different, not noisy but how a v4 should sound. Can now use cheap fuel!! Expensive to have replaced though. Could be done by a competent home mechanic but remember the word competent:)

Will this not affect the MOT emissions readings/regulations?

Ed_Case 30-05-2010 22:01

Quote:

Originally Posted by Monkey Butler (Post 1228525)
First of all I must attribute the suggestion to someone from another forum found by googling randomly - johnny.chadda.se
The fully reversible "pair, flapper and snorkel mod":
1. lift tank and disconnect the pair control valve twin plug connector located at the rear of the air filter housing. Protect plug and socket as appropriate
2. disconnect the vacuum hose from the air filter housing intake system diaphragm unit. Plug the hose and the diaphragm port as appropriate. Secure the hose to prevent movement.
3. remove the soft rubber snorkel at the front of the airbox. Keep it somewhere safe.

Not being a mechanic myself, I work on the principle that if a part is there, then it does something necessary & removing it may cause another problem elsewhere (perhaps not obvious at the beginning). Is there any update on this mod Monkey Butler?

Ian Daly 31-05-2010 12:26

Quote:

Originally Posted by Ed_Case (Post 1276429)
Will this not affect the MOT emissions readings/regulations?

Bikes aren't emission tested, are they:dunno:

Ian

Ed_Case 31-05-2010 14:22

You're right, just checked, it's only the condition of the whole system & BSAU stamp that is required, no emission check, (probably only a matter of time though) silly me,:bang: should have checked before posting not afterwards..:toilet:

kaldek 21-06-2010 02:04

Vacuum dampers not an awesome idea
 
Hi folks,

I posted a couple of months ago about testing vacuum dampers. Anyway, the short answer is it's not a good idea. The long answer is my problem which I was twiddling with vacuum dampers to dix was ACTUALLY stuffed and fuel injectors which were leaking. Pretty much every test I did after that was a waste of time with invalid results until I had the injectors replaced (with units from an '06 model).

I tried a factory vacuum damping chamber from a Suzuki DL-1000 VStrom, and it made the bike stall because it not only damps pulses but also restricts flow and causes lag in the data getting to the MAP sensor. Pulling up at a quick stop with the clutch in would cause the bike to either stall or almost stall. Not good!

Having said all this, my '02 running '06 flow-matched injectors (with a PowerCommander V and Autotune) runs very well indeed. The bike has Motad headers, Staintunes, K&N filter, O2 eliminators and PAIR-valve block-off plates. I have not disabled the flapper valve.

greenman2 02-05-2011 21:03

I plead guilty to doing the Johnny Chadda mod. I've only had a short run out since but fuelling seems much improved. The instructions are very clear and it is fully reversible.

I can see the point about not changing Mr Honda's design, but it's based on an assumption that manufacturers get it right all the time and their standard bike will meet everyone's needs equally. Quite clearly this is not the case with fuelling on the VTEC, and Honda aren't the only guilty parties and it wouldn't be the first time trial and error by informed owners was able to sort out an OEM problem.

Update: done about 200 miles today on all sorts of road, no downsides at all. It used to be particularly bad when slowly filtering through traffic and I did enough of that today, pickup from 5,000 revs is much improved and I can ride without looking at the rev counter all the time- I didn't realise how much effort I have been putting in to riding around the problem.

offshorepaul 05-05-2011 05:46

Sorry about this question! I have a 08 vtec and it is affected by this problem this thread has been talking about. Low revs open throttle and bike runs away.
I have tried to read and understand the thread but am failing.
Quick one, can it be fixed, how much and by who?
Kind regards
Paul
:sofa:

greenman2 05-05-2011 20:59

Paul,

I would recommend the Johnny Chadda mod, it's easy to do, instructions are clear and it's completely reversible.

http://johnny.chadda.se/article/pair...l-mod-for-vfr/

Dave

offshorepaul 05-05-2011 21:48

Thank you very much Dave, Its all become clear!
I shall do this when I am next home. Great idiots guide, just what I needed!!
I hope it cures the surge at low speed.
Very kind regards
Paul

s3achris 05-05-2011 22:20

Just to add my comments. I did the Johnny chaddha mod last weekend (02 VTEC) with all the usual low rev problems the results are fantastic (also there is a thread called airbox mod with similar comments).

The only thing I didn't do was the snorkel mod - opinion seems to be that the intake noise makes the bike sound better (not a bad idea!) but this may have an adverse effect if ridden in very wet conditions. I have staintunes fitted so I don't really need any extra noise!

All I can say is that by disconnecting the PAIR electrical socket and blocking the flapper valve tube - you should have a new bike and the word 'revelation' will fill your mind........... Enjoy!!

moonster 08-05-2011 15:29

Quote:

Originally Posted by s3achris (Post 1322359)
Just to add my comments. I did the Johnny chaddha mod last weekend (02 VTEC) with all the usual low rev problems the results are fantastic (also there is a thread called airbox mod with similar comments).

The only thing I didn't do was the snorkel mod - opinion seems to be that the intake noise makes the bike sound better (not a bad idea!) but this may have an adverse effect if ridden in very wet conditions. I have staintunes fitted so I don't really need any extra noise!

All I can say is that by disconnecting the PAIR electrical socket and blocking the flapper valve tube - you should have a new bike and the word 'revelation' will fill your mind........... Enjoy!!

I can't believe it either!!!! I have a vtec 02 and although the fueling wasn't as bad as some have reported, it was still there.
I have only just got this bike and it was the first ride out today. I decided to cut short the ride and come home to do the mod' Well, I disconnected the pair valve socket and also the flapper valve tube and it is just amazing just what difference it makes. I too have staintunes fitted. I would not believe it if I hadn't done it myself!!! no more hesitation around the 4k to 5k revs
many thanks for the post I too now have the vtec I always wanted.:beer::beer::beer:

Tarmac Bob 08-05-2011 19:11

Same here, read the instructions with interest and a little sceptical about the scale of claimed improvement if I'm honest but I did the mods yesterday on my 02 Vtec and the difference is indeed remarkable - smooth fuelling all the way to 7200 and a much smoother transition when the extra valves open up. It'll be interesting to see what happens to fuel consumption over this next tankful.

Cheers Johnny Chadda!

moonster 08-05-2011 19:41

Quote:

Originally Posted by Tarmac Bob (Post 1322696)
Same here, read the instructions with interest and a little sceptical about the scale of claimed improvement if I'm honest but I did the mods yesterday on my 02 Vtec and the difference is indeed remarkable - smooth fuelling all the way to 7200 and a much smoother transition when the extra valves open up. It'll be interesting to see what happens to fuel consumption over this next tankful.

Cheers Johnny Chadda!

do you suspect the fuel consumption may suffer?:dunno:

Tarmac Bob 08-05-2011 19:48

Quote:

Originally Posted by moonster (Post 1322706)
do you suspect the fuel consumption may suffer?:dunno:

No I think it may improve from 40-43 on the basis that the engine no longer thinks its running lean and bangs extra fuel in - re explanation in the original Johnny Chadda article if I read it right. Mind you, I'm not very mechanically minded and probably more of a blind optimist :d::d::d:

Tarmac Bob 08-05-2011 19:53

Quote:

Originally Posted by Tarmac Bob (Post 1322709)
No I think it may improve from 40-43 on the basis that the engine no longer thinks its running lean and bangs extra fuel in - re explanation in the original Johnny Chadda article if I read it right. Mind you, I'm not very mechanically minded and probably more of a blind optimist :d::d::d:

This is the bit I clocked...

The reason for this is that the VTEC model had an O2 sensor fitted in the exhaust. What happens is that the PAIR valve is working pretty much from idle speed blasting fresh air into the exhaust system. The fresh air entering the exhaust is picked up by the O2 sensor which then thinks the bike is running lean (around 19:1) so sends a signal to the ECU to richen up the fuel mixture. The ECU is now pouring as much fuel into the engine as it can because the O2 sensor thinks its still running lean. The real fuel/air ratio being poured into the bike is now around 11:1 making the bike hard to ride and resulting in the snatchy throttle response we have all been talking about.

moonster 08-05-2011 20:09

let me tell you a story Tarmac Bob,
It all started a couple of years ago when I bought a '06 vtec. A lovely looking bike in candy red with 5k on clock. The fueling was very snatchy from about 4k to 5k revs................so after reading a lot of "cures" some from this site, I balanced the sv's, I bought a pair of remus cans, very slight improvement, next 02 eliminators, no signs here. K&N filter, power commander very slight change but still that surge on over run! by this time I'd had enough! and spent about a grand!!! so it had to go. 2 years on and I want another vtec ( poss' had a "bad" one before) so I buy this one and find a marked improvement on the last vtec. just this niggling hesitation around 4k to 5k revs, I could certainly live with it but I took a chance and did the mod...........thank heavens I did . I hope it stays this way!!!:beer:

Tarmac Bob 08-05-2011 20:15

Quote:

Originally Posted by moonster (Post 1322711)
let me tell you a story Tarmac Bob,
It all started a couple of years ago when I bought a '06 vtec. A lovely looking bike in candy red with 5k on clock. The fueling was very snatchy from about 4k to 5k revs................so after reading a lot of "cures" some from this site, I balanced the sv's, I bought a pair of remus cans, very slight improvement, next 02 eliminators, no signs here. K&N filter, power commander very slight change but still that surge on over run! by this time I'd had enough! and spent about a grand!!! so it had to go. 2 years on and I want another vtec ( poss' had a "bad" one before) so I buy this one and find a marked improvement on the last vtec. just this niggling hesitation around 4k to 5k revs, I could certainly live with it but I took a chance and did the mod...........thank heavens I did . I hope it stays this way!!!:beer:

Glad for you mate :beer::beer::beer: its a swine when you keep doing mod after mod to a bike to try an solve a problem and you never really get it sorted - you get rid in the end because you lose confidence in the bike. I hope - well actually, I'm confident that the improvements in smooth fuelling will be permanent and not lead to any other issues - because of the explanations given in the article about what's being done and why. Better fuel consumption would be a bonus to be honest.

s3achris 09-05-2011 22:03

Quote:

Originally Posted by moonster (Post 1322706)
do you suspect the fuel consumption may suffer?:dunno:

2 weeks into my 'new' bike and my theory is that the fuel consumption is likely to be better because I am able to ride the bike more smoothly, I can trickle along at lower revs, hold the cruise at 5k where it used to be at higher revs and without doing any calcs my gut feeling is that consumption is no worse than usual..................as a hobby rider, I can say that even if it's worse, I could live with this new set up.

My only regret is that I've had the bike unmodified for over 4 years and cannot believe how such a simple mod can make such a huge difference. The other thing that has changed beyond comparison is the total elimination of the vtec transition - it has totally disappeared. On Sunday, I was deliberately cruising along in top around 6800 (close to a ton officer) and I could not detect any surge or hesitation (the bike was up to temperature!)- just perfect..........!!!

I was getting close to getting rid of the bike because of this poor running - now I may never change!!

moonster 15-05-2011 14:45

just done 203 miles on 17.5lt of fuel = 53 mpg so I'm happy:)

dom_f 15-05-2011 19:10

Quote:

Originally Posted by moonster (Post 1323676)
just done 203 miles on 17.5lt of fuel = 53 mpg so I'm happy:)

I make that 51 but still good :)


Dom

moonster 15-05-2011 19:20

Quote:

Originally Posted by dom_f (Post 1323698)
I make that 51 but still good :)


Dom

Back to school for me then?:blush:

moonster 15-05-2011 19:31

52.7 mpg according to google conversion?:dunno:.............getting boring now!

greenman2 15-05-2011 19:58

On my regular commute I usually do 180 miles before the warning light comes on, firsdt run after the mod and I got 172, so maybe a small increase but nothing much. Am I bovvered??

dom_f 15-05-2011 21:06

Quote:

Originally Posted by moonster (Post 1323706)
52.7 mpg according to google conversion?:dunno:.............getting boring now!



Looks like it's me that needs to go back to school :blush::blush::blush:

diri32 16-05-2011 14:05

Hi all
 
Quote:

Originally Posted by greenman2 (Post 1322339)
Paul,

I would recommend the Johnny Chadda mod, it's easy to do, instructions are clear and it's completely reversible.

http://johnny.chadda.se/article/pair...l-mod-for-vfr/

Dave

Well this sounds like my dream of riding a proper vfr could become a reality.
I had to sell my vfr vtec back Dec 2007 for throttle control problems.
Is it safe to say, that I can trade my cbf1000 for vfr vtec?
Or am I about to make same mistake again for waisting my hard earned cash on a vfr?
Is Johny Chadda pair valve disableing the miracle cure every body was waiting?
thr vfr vtec i sold in 2007 had far worse faults, It was cutting out while riding/filtering, which made it unsafe to ride, so It had to go.
I will welcome any input on this guys.
My current bike CBF1000abs, I can say that quality is no match for the vfr anyday, including relailablity.
VFR VTEC is simply better Bike/machine in any aspect, My opinion. like difference between a Jag and Ford focus.
Kind Regards
Diria

diri32 16-05-2011 17:02

Hi All
 
This mod sounds very tempting, I am worried it will have no effect on bike after I buy it.
Then I am back to square one.

moonster 16-05-2011 17:58

Quote:

Originally Posted by diri32 (Post 1323823)
This mod sounds very tempting, I am worried it will have no effect on bike after I buy it.
Then I am back to square one.

would you like to expand on this?:)

diri32 16-05-2011 18:59

Hi
 
Quote:

Originally Posted by moonster (Post 1323831)
would you like to expand on this?:)


i am talking about chadda's mod.
I tried to post earlier but, Some how it is not listed.

moonster 16-05-2011 19:37

all I can add is that over the years I've had four vtecs in total and this is the only one which has run properly (only had 2 for very short time) and one I had to spend a grand to get it anywhere near ok. I wish I had known about the mod way back then!. the thing is ........I dont know the long term effect, if any, this may have on the bike.:eek:

moonster 16-05-2011 20:53

Forgot to add.........since the mod the bike now runs at 77degC as opposed to 82degC before mod. so...........must be running richer= cooler?
could this mean the ecu is running a "base map"?:dunno:

Topper Harley 11-06-2011 14:39

Gidday all,

New VFR VTEC owner here! I encountered the dreaded 'surging throttle' problem at lowish RPMs on my '05 VFR, and after doing some research online, discovered that I wasn't alone. I struggled to believe that my limited knowledge of engines was better than the very clever chaps (and chappesses) at Honda who designed the bike, so I am loath to go tearing pieces off and blocking things. So, I consigned to putting up with the problem and had adjusted my driving style to avoid it (don't go below 4000RPM, slip the clutch around slow speed corners, etc...).

Blocking off the PAIRs valves as described in this forum seems to have had a beneficial effect on the 'drivability' of many peoples VFR's, so it was something I would consider if the surging got too frustrating. But then....

I have only ever filled the bike up with 95 Octane (usually from a supermarket) and have covered about 3000 miles over 6 months. But on a recent motorbiking trip around Wales I decided to try 97 Octane - mainly to see if I got better range out of each tank. And something quite unexpected happened:

After about 20 miles I noticed that the throttle surging had significantly improved. I could also run the bike down to sub 3000RPM while in gear without it juddering or surging! And, after 50 miles on the better fuel, not only had the surging at constant throttle mostly gone, the power jump when the VTEC kicked in was far less noticeable. It felt like I was riding a new bike! Far smoother and more powerful at lower RPMs. It didn't really affect anything above 7000RPM, but it really helped torque and throttle smoothness from 3000 - 7000.

400 happy miles later I was forced to refuel on standard 95 (I was on fumes and there was no 97 available), and - you guessed it - all the previous problems immediately reappeared. Bugger.

So I'm interested to know: using 97 fuel makes my un-modified VFR run far better. Has anyone else experienced this quirk? I now only run 97 Octane and am very happy with the result. I've read some threads that state we should only use 95 fuel as 97 is just an expensive hoax; but I beg to disagree. Mine seems to love the stuff!

Anyway, just thought some might like to hear about my experience. I hope it helps.


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