Inconsistent Surge And Loss On Power On Highway

[SlimWhitey]

Right, so, now I've got an actual running issue with the bike.

Going down the highway, or just cruising around in general between 5 and 6,000rpm, I get a surge and loss of power. Inability to accelerate. Does not happen consistently, just comes and goes.

It has, on one occasion, happened above 6,000. But has not happened since.

No FI light. If I drop down to about 4,000rpm, it goes away, and I can accelerate back up where I want to be. During the surge, I have a real loss of power, no ability to rev the bike (full throttle might as well not exist) and The bike just generally acts like it's out of fuel or sputtering.

Ideas? I don't know enough about the engine/driveline to diag it without other knowledge. A quick google search has not yielded much (although perhaps I am searching the wrong things).
Any guess I have is a shot in the dark.

[SlimWhitey]

mm, should note: currently reading the pinned topic called "surging surging surging" to see if it has anythign for me. however, looks like it is all about the 6th gens.

[MaxSwell]

While I've never experienced your specific issues, one easy and free thing to try is to lift up your seat and find your ECU. It's under a plastic cover right under/ahead of your taillight. A couple of times I've corrected a difficult to diagnose problem by unplugging and replugging the large connectors of the wiring harness to the ECU.

Good luck.

[SlimWhitey]

Will try it.

Wish I could get a scan tool for a bike. makes Diag way easier.

[Auspanglish]

Check the common earth bus connector in the front subharness... there's a thread on here titled "Urethra" or to similar effect... I'll try and link you to it...

Here: http://www.vfrdiscussion.com/forum/index.php/topic/66045-urethra-i-found-it/?hl=urethra

Then you gotta check the large grey and blue connectors and do the earth wire fix there too... there's another thread on here somewhere. (Sorry this may be 6th gen specific)

Then I would check to see that the O2 sensor plugs are connected the right way around... apparently they are sometimes switched around out of the assembly line... you'll need to download the workshop manual and go over the wiring diagram and check the colours of the wires and connectors and their correct (or otherwise) positioning.

You could also try cleaning out the PAIR valves.

Make sure your battery is properly charged and in good condition. May sound odd but it is an electronically fuelled bike so the electrical system has to be in good maintenance. ON the same track, check your stator output and R/R diodes. Just in case. Follow this How-to:

http://www.vfrdiscussion.com/forum/index.php/topic/15-electrical-test-rr-stator-and-battery/

[KevCarver]

Check out the Reg/Rec and the connectors. See if they are crispy and melted. On the tail subframe, left side.

[SlimWhitey]

i'll take er apart tomorrow after work and give the r/r a visual go over. gotta get hold of a multimeter for some of this it seems as well.

I doubt the o2 sensors are switched, however. I've ridden it for about 10,000km and it started doing this about 1,000 ago. although today I rode it 450+km and it didn't skip a beat.

I had the PAIR valve cover off the back valvetrain cover while doing the valves (so I did not need to remove the airbox) and at the very least, the back looked alright. not excessively bad, wee bit of carbon buildup.

I was told to check the TPS while I was at it. gonna look into that tomorrow.