1500 to 2500 hesitation/sputter

Depends on if VTEC is kicked in...:vtr2:

 

Hey, Bunky, dincha hear ?? Honda 100% eliminated fueling problems when they finally threw out those balky, old-fashoned carbs back around 1998. Now computers run everything in a perfect digital world.

Remember that a typical factory service manual has about 10 pages in the carb service chapter but evolved to about 45 pages to explain the complexities of injection. I know i don't need it !

 

Na, it's the tree hugging Hippies and their pollution laws that screwed everything up. Like I mentioned above I found my still standard '99 gen 5 mk 1 first single holed injectors had way better fueling than my 12 holed '03 build gen 6 injectors. Honda overreached itself by trying to meet California's projected very strict '08 emission laws when the gen 6 came out late '01.

I know at least one guy whose '98 gen 5 had 230,000 kms on his with zero problems with his injectors in that time, suspect most carby'd VFRs may have been kitted or cleaned by then.

 

I have the same low-rpm hesitation/sputter as neptech described (even with a warm engine), on a bike with ZERO mods. What do I do?

 

Quote from Bassie on VFRD

-Quote: What this mod does is simple, it tell the ECU that your Lambda-sensor is connected, nothing more nothing less.

A working sensor does provide a voltage to the ECU to what the ECU responds by using some sort of mapping.

Because the mod omits the voltage, the ECU will think the sensor is broken, it knows this after about 3 minutes.

You can smell this during starting as the ECU keeps pumping extra fuel that doesn't ignite well, as such the exhaust will smell a lot after petrol.



As the ECU notices that the "sensor" doesn't respond to it's regulation it assumes it's broken and starts a special optimized combustion-program that has static parameters.

This special program is optimal, and you know it as the power is there and the response is brilliant!

It's also this program that the power-commder uses to control the injection.



However, you do not need a power-commander, the optimal program is already in the ECU and works as expected.

There is instantly a lot of extra power and torque, if you wait 3 minutes after starting.



I have done this mod on a VFR800Fi 2000 and a CBR1000RR, and on both machines the results are great.

Also, this mod makes the ECU just respond to the throttle and not to the O2/CO2-level anymore, as it thinks the sensor is broken.



Yes when you start it smells bad, but it quickly returns to normal with an improved riding experience. -end of quote


The Problem I am having is it seem to stay on the rich side, smelling gassy although the engine does not run hot. No hotter than VFR's do....

 

I have a similar stumble/stutter, usually between 2500 and 3000. If I get on the gas, it goes away. If I get above 3500 or 4000, it does away.
I have covered the holes that the PO made in the airbox, and bought a snorkel to mount since there isn't one.
I have a PC2, but there's no telling how it was set up, and I'm probably not going to pop for a few dyno runs to do it.