2008 TE running poorly - stalling, stumbling, surging,fixed:bad fuel pump

Over two weeks, with a 10 day trip in the middle, I pulled a chunk of my bike apart and got it back together. Reworked suspension (thank you Les) installed. Exhaust valves adjusted. Air filter cleaned and oiled. Trail Tech X2 installed. New Coolant. And all that involves - pulling the tank and so on.

Finally, I get her out for a ride to a friend's house. I rode her gingerly to the gas station a mile away. I can't remember if she ran well or not until that point. I was paying attention to the suspension and how hard it was to shift with the running shoes I was wearing (not ATGATT! oh dear god!). The suspension felt awesome already. I was aiming for every pothole, rut, curb, whatever. Supple yet firm - and not even set up yet.

I fill her up and head to the friend's house. Sputter. Stall. Sputter. She doesn't want to run. WTF? Finally she's going but won't accellerate without lots of chuffing and stumbling. Something is very wrong. I wasn't going very far and figured she'd swallowed something in those weeks and just needed to burn it through (how's that for scientific?). Nope. No go.

Runs like crap.

Suggestions/guesses:
1. Bad fuel. I drained the gas and put in a fresh gallon. She runs no better.

2. Checked spark plug to see if it had been fouled or ??? Looks mostly fine. A little extra carbon, but that's to be expected with how it was running.

3. Valves. It's been suggested that I did a piss poor job of adjusting the exhaust valves. Specifically that I wasn't really at TDC and that the decomp lever influenced my adjustment. Considering that I only turned the adjusters less than a 1/16th turn to tighten them up, I'm not inclined to think that's it.

4. Bad connector under the headlight or elsewhere. Someone over on ADV reported a somewhat similar issue related to a bad connector after fiddling with their headlight, but they had no idea which it might be. I didn't see any issues and it's hard to know if what they reported applies.

5. Fuel filter ???? Is there one on this beast up in the pump or ?? I could see a clot of bad gas and water causing this if it clogged a filter. But ???

I'm about to dig into those exhaust valves, but I really don't think they're the problem. Any guesses? I'm almost convinced it was some bad gas. Is there a fuel filter on this beast? I really can't remember how she was running before the gas station and may have attributed it to being cold.

I'm not happy.

Ran great. Less than 3,000 miles on it so far (new speedo a month or so ago so not quite certain of total mileage).

Ya, I'd take that tank back off and check all the wiring. Elsewhere in this forum one of our guys posted that he found loose coil connections and tightening them up really cleaned up the bike.

Re crimp the connectors on the coil wires so they are tight.

One more thing to try: pull the Air Filter out and see how it runs.

Thanks folks. I'm trying to resist the urge to find a trailer and haul it down to the dealership.

Doesn't run any better without the air filter. Checking all the connections now...

Damn, sorry to hear this 'stump the chumps' thing is still going on

....the fuel filter is attached to the pump, in the tank.

....since you had the tank off, and you probably already did this, but
check the quick disconnects to see if they are seated correctly, and the lower fuel line goes to the "IN" spot on the fuel pump, and the petcocks are on.......

Bike's at a good shop right now. They are, at last check, still stumped.

I pick up my bike tomorrow. It's running!
Trying to diagnose the problem, they'd done all the usual stuff - checked for error codes, checked the valves, camchain tension, that the fuel pump was running, etc. They'd swapped out the computer and related bits. And it still wasn't running. In a last ditch effort before swapping out the throttle body, they swapped out the fuel pump (by simply swapping tanks). And it ran "perfectly" (quoting the wrench). Woohoo! The old pump pumps plenty of gas but clearly something was wrong.

It's nice to know I didn't break my bike.

Woohoo indeed, great news!

I'm not sure how you tested the fuel pump, but just a thought - did the problems start immediately each time you started riding? I ask because I had a problem once where the vent in the tank cap on my Fireblade was blocked and the bike would start but then fairly quickly it couldn't suck fuel out of the tank and it would run badly and eventually stop. Each time it stopped I took off the cap to make sure there was still fuel in there, so it would then start ok but after a few minutes the problem would reappear, until I realised it would only run after I'd just removed the cap! Maybe the pump was running ok but having trouble sucking enough fuel?

If you could see the sides of the tank starting to suck inwards that might be a clue.

Since they changed the tank they may have ended up using the cap from the other tank. Of course, maybe it really is just something wrong with the pump itself and I guess it doesn't matter now anyway if they're giving you it back in full working order, I'm just curious.

I agree with Petem, check the cap and valve on the old tank.

I've had the problem on a bike before! Watching a tank deform can be a little dramatic, can't it?

However, venting isn't the problem in this case. The bike struggled to start, and ran better at WFO than not. A couple times I didn't bother to hook up the vent line and just left the bung uncovered - and it still ran poorly.

excellent call

I was just thinking the same thing after I read "fuel pump still pumps plenty of fuel". Fuel tanks have to vent even with fuel injection. Laws of physics dictate that when matter moves the space it leaves must be inhabited by something else, meaning: if you move the fuel out air has to displace it. At some point, once enough vacuum has been pulled, the pump will struggle to move the gas. My bet is it has that crappy one-way valve in the line, or the end of the line is stopped up, or maybe even the cap is stopped up. I bet they only tested the pump afte they replaced the tank and probably did so after opening it or with the cap off. A new vent line and or cap would most likely have solved the problem. Sorry I didn't see this before now. I might have been able to save you some grief as I've seen something like this before on other bikes, but since the "general" forum has been so widely redispersed into other forums, these type topics tend to get put into more specific places. Most of which, most of us don't tend to look unless we own a bike of that specific model.

Sorry I didn't catch this sooner. I might have been able to help, but at least you're riding again. I'm looking forward to getting my seis-dies.

Could have been the cap.

Tiny update:
The pump was replaced everything runs great. Same cap, same vents, etc.