I've read a lot of threads about the common surging problem people have with VFRs, but I can't understand what would cause the surging to only occur in one gear out of the six.
Chain tension, O2 sensonrs, and/or throttle body sync should affect them all, no?
Does the fuel injection map change in different gears?
My surging is only at low throttle in 3rd gear. All other gears run fine.
[image: View Post]horwitzs, on May 30 2009, 07:41 PM, said:
I've read a lot of threads about the common surging problem people have with VFRs, but I can't understand what would cause the surging to only occur in one gear out of the six.
Chain tension, O2 sensonrs, and/or throttle body sync should affect them all, no?
Does the fuel injection map change in different gears?
My surging is only at low throttle in 3rd gear. All other gears run fine.
Thanks for any input.
The fuel injection map is the same for all gears. Usually surging is a fuel mapping or starter valve problem.
But, like you said, none of that is dependant on what gear you're in.
Perhaps it is popping in and out of gear and it feels like surging? Does it happen at low throttle openings at all RPM ranges? What changes have you made from stock?
Shouldn't be a worn chain... only 500 miles on it and I've made sure adjustment is not too tight.
And it definately isn't popping out of gear. I have a lot of riding experience on a variety of bikes so I know what that would feel like.
It happens at low throttle up to about 4k rpm... but only if I am holding steady throttle. If I let the rpm drop a bit and gently load the engine, slightly accelerating it doesn't happen, but if I ease off to hold a steady rpm it surges dramatically. And like I said, no problem at all in other gears.
Mods from stock are:
Staintune exhausts
PCIII
K&N air filter
O2 sensor eliminators
one tooth smaller countershaft sprocket
speedo healer
[image: View Post]horwitzs, on May 30 2009, 07:31 PM, said:
It happens at low throttle up to about 4k rpm... but only if I am holding steady throttle. If I let the rpm drop a bit and gently load the engine, slightly accelerating it doesn't happen, but if I ease off to hold a steady rpm it surges dramatically. And like I said, no problem at all in other gears.
That's what I figured, the common emissions check zone. Since it's the easiest thing to try, I suggest swapping FI maps.
[image: View Post]FotoMoto, on May 30 2009, 07:53 PM, said:
[image: View Post]horwitzs, on May 30 2009, 07:31 PM, said:
It happens at low throttle up to about 4k rpm... but only if I am holding steady throttle. If I let the rpm drop a bit and gently load the engine, slightly accelerating it doesn't happen, but if I ease off to hold a steady rpm it surges dramatically. And like I said, no problem at all in other gears.
That's what I figured, the common emissions check zone. Since it's the easiest thing to try, I suggest swapping FI maps.
I am moving in a week to my next job site in a different part of the country, so we'll see if the new climate changes anything with the FI. If there's no difference, I have another map I've held in reserve that I will give a try.
Mine is the exact same! I swear third gear is different! I've come up with a couple maps that help alot. PM me with your email and I'll send them to you, or anyone else. I've been meaning post them in the download section but I'm still fine tuning. I little input from someone else might help with that fine tuning.
[image: View Post]horwitzs, on May 30 2009, 06:41 PM, said:
I've read a lot of threads about the common surging problem people have with VFRs, but I can't understand what would cause the surging to only occur in one gear out of the six.
Chain tension, O2 sensonrs, and/or throttle body sync should affect them all, no?
Does the fuel injection map change in different gears?
My surging is only at low throttle in 3rd gear. All other gears run fine.
Thanks for any input.
End of thread · 8 posts recoveredWayback Machine snapshot 12 Apr 2010