VFR800 Vtech hesitates

Hello, been having intermittent "hesitation" issues with my 2007 VFR800 Vtech.
This culminated in the bike breaking down recently. This was found to be due to a very loose battery connection. Removed , cleaned and refitted battery connections and all was well. Super smooth.
Now the bike is hesitating again (intermittently) at 5500 and again at 8500. This is worse when the throttle has to be constant, at 30 or 40 mph.
Bike has been regularly serviced including injectors balanced, and has done just under 20k miles and run the bike on Shell V-Power fuel most of the time.
This hesitancy has been a problem for some considerable time and I thought I had it beat when I found the loose battery connection.

 

Have you tried fitting 02 eliminators? It totally transforms the bike for me!

 

Hi and Welcome to the MadHouse:welcome:.

When you get time please swing by the "introductions" section of the forum to say Hi to the rest of the folks on here. You may want to update your forum profile (Forum Actions/Edit Profile) to include the specs of your bike and an approximate location city/town is fine -that way they will appear automatically beside your posts and if you need help you may find someone living nearby is willing to drop by and advise especially if you have a well stocked beer fridge. PS remember to post up a photo or two of your bike or you may find folks raggin on you.

:focus:

I understand your desire to keep your post concise - but I suspect you know but have left out pertinent information which might help others - often thousands of miles away to offer sensible input. So could you give us a bit of general information on this bike and its recent performance. Have you just purchased it? Do you know that it was working well for a period before this issue arose? Have you made any modifications to the bike which might be pertinent - fitted a power commander - pair delete...

Inevitably at this stage its mostly guess work as to what is going on... so these suggestions may be well off.

Once you refitted the battery terminals you say the bike was running fine for a while - so how long - are we talking hours or many months? The fact the bike has been running OK for a while suggests it is more likely to be something electrical (a loose sensor connection) rather than mechanical fault with the vtec system.

So assuming you have checked that the battery terminals are still tight, I suggest you watch out and note down any other symptoms which appear when the bike is running rough - dash board lights etc - if you have a volt meter fitted are the volts dropping below 13 at any time with the engine running as this might indicate charging system problems? I guess you know that vtec is disabled until the bike reaches a minimum safe operating temperature so if the problem is only evident with the bike cold let it idle for a bit and see if it sorts itself out once it gets over 80c. Obviously if there is a fault with the temperature sensor/wiring it would have similar effects.

Good luck and let us know what you find.



SkiMad

 

Steve, No, what are they and where do I get them?
Are they easy to fit?
Thanks

 

SkiMad
Thanks for the reply. I'm new to forums and need to get the bike sorted now!
Background:
We've had the bike about 8years, from about 5k miles. It's not modified in any way.
All was fine for the first three years when it began, from time to time, hesitating.
Been checked at a Honda centre and no faults found. At the last service I insisted that the mechanic road test the bike - all was fine.
After a couple of hundred miles it started playing up again.
This has been the scenario off and on.
Last year we put 4k miles on the bike including a tour of Scotland. Journey there was fine but we had the problem again whilst touring around and on the way home. I have dosed the fuel with Forte injection cleaner from time to time.
It's the fact that it is intermittent that make it annoying. It's on it's last chance as we no longer enjoy riding it.
Checked voltages at rest, tick over and charging and all okay.
Engine is warm when problem occurs.
Yesterday again I took it for a run. About 24 miles round trip. 30mph, 40mph, lanes and dual carriageway.
The bike was warm as we had just completed a run.
All was fine on the outbound run. Then had the hesitancy at 5500 and 8500 rpm, then it cleared. It hesitates at other times.
I'll try and find the "O2 eliminators".

 

All they are is 330 Ohm resistors which are inserted in the socket for the plug from the O2 sensors in the exhaust. But unless you have a Power Commander (and if you do, it would have come with these), I don't see how they would help you.

Is there any chance that all that is causing your intermittent problem is bad fuel? Does the bike sit for extended periods? Do you normally buy your petrol from the same station?

Just a thought...

 

Maybe time for new plugs. Also check coils that are at the plugs on newer bikes. I found the 10mm bolt on one coil loose on my 2003. Possible water in the tank? Constant speed gas doesn't slosh around. Don't worry about O2 eliminators at this point.