Scary throttle response.... sometimes

Hi all,

New member here but long time lover of VFR800 (sounds a bit wrong :witless

Bike rides a dream. Accelerate from standstill or rolling start through the rev range without skipping a beat.

Bike = VFR800 FiY (2000) - Completely Stock - This is a NEW problem
Problem Scenario
Running at constant throttle between 4500 and 6000 rpm, doesn't matter which gear.
Let's keep things simple and say I'm riding at 75mph in 5th gear.
With a constant throttle the speed starts to slowly drop away. After a drop of 5mph I apply a little throttle.... nothing.... a little more.... nothing.... a little more and WHOOSH! Off like a scolded cat!
Needless to say if this happens mid-bend its extremely unsettling (that only happened once mind you, wary of it now)

Garage didn't come up with anything useful ("try running a better fuel mate" :numbness. Have done the basics, air filter and plugs (needed doing anyway).

Ideas please?

 

Welcome. A little more info might help, what year is your bike? Few pictures will help you from getting razzed!

Just looked through my 2003 manual and the Programmed Fuel Injection has to be the most complicated part of the bike, there are sensors, speed sensors, air sensors that feed info to ECU.

 

Hi awsbikes

Welcome to the MadHouse. :welcome:When you get a chance swing by the introductions sub-forum and say Hi to the folks and when you do include at least one picture of your 800. (You can upload pictures using the icon two to the right of the envelope and following the prompts).

Hopefully others will be along shortly to help you trouble shoot this one - although my first thought was it may be the throttle position sensor connector has worked loose giving intermittent signals or the sensor is starting to go south after 14 years service. It may be worth checking to see if there any MIL(Malfunction Indicator Light) warnings as if there are faults registered it may help troubleshooting the problem? - try this - http://www.youtube.com/watch?v=MpHK7gMx2WY

Take care




SkiMad

 

I'm not sure about the 5th gen but my 6th gen (2004) had the same "jerky" throttle response when running constant RPM's. I did several mods at once so I can't point to any one fix but I basically got rid of all the environmental stuff. I got rid of the evap canister, pair valves, catalytic converter, opened up the flapper on the airbox. I then added some Leo pipes and a pciii with the O2 sensors disabled and a custom map. The throttle response is smooth a silk now and no more surging.

I know your bike is a 5th gen but here is a link to a discussion for 6th gens about poor throttle response and the effects of some mods to fix the issue.
http://vfrworld.com/forums/showthread.php/21585-VFR-VTEC-2008-Throttle-issue!-(another-one)

 

I've checked out the video and will look for codes.
Hopefully this will give me more to go on.
Many thanks SkiMad!