Stubborn R6

[Kurlon]

I've been working on a semi-basket case 2003 R6 off and on since February. Race bike, crashed, was put away wet and then a young racer snagged it to revive but ran into two small problems: 1) No mechanical training and 2) No budget due to breaking his shoulder blade and thus no lawn mowing. So I got it. Some of the stuff was pretty easy to sort back out, front brakes self locking due to a dirty, dirty master cylinder that was plugged up, etc.

Where I'm flailing is with the motor. When it arrived it would start, with heavy coaxing from the throttle. It would run rough, throttle response was delayed, as in seconds, kinda creepy. Hit the throttle and it'd bog, close it and a second later it'd build revs all of a sudden. Whacky crap. Tank had either diesel in it, or the worst aged out gas I've ever seen. Yanking the PC3 eliminated the odd throttle lag. Leak down test showed one cylinder clearly had multiple valves hanging open, borescope showed serious carbon / crap buildup in all four. Pressure plus a hammer cleaned the crap off the valves, swapped the two shims that needed tweaking after, rebuilt the fuel pump, cleaned the throttle bodies, injectors were all professionally cleaned and balanced, plumbing and wiring cleaned up, new airfilter to replace the decaying 'thing' in the airbox...

Still doesn't run right. It fires up cold, idles beautifully. It'll snap to on small throttle movement. If you give it a full twist at low RPM (6k and below) it'll bog / stumble / misfire and not build revs. Ease it up around 8k with light throttle, whack it and you get full song of it's people. I've no place to road test, so this is all on the stand, in neutral or 6th for max 'load' doesn't matter. It's running SO much better than when it arrived, but clearly something is still out of whack. It's got a slip on exhaust, I don't think it's a full system, I've added slide stops, other than that it's stock. I have a PC3 which I've updated to current, it was literally on the first shipping revision, I had to get a rev box to update it... I have the Graves sample slide stops 03 R6 map loaded, it expects a full exhaust and I think a different air filter, but the bike behaves the same with or without the PC3 connected. The map really doesn't tweak much.

It might just be in desperate need of a remap, but I can't imagine it running so badly off the stock ECU with as few mods as it has. This has me hesitant to toss it on a dyno just yet only to find out that mapping isn't going to cure it. I suppose it could be a 640 monster motor in disguise... but I'm not holding my breath on that one just yet.

What's the hive mind got for suggestions on what to check next?

leakdown - good
compression - good
valves - adjusted, timing as per service manual
new plugs and coils
new OEM air filter
injectors Pro-Flowed
throttle bodies sync'd at both idle (bleed screws) and 1/3rd throttle (butterflies)
fuel pump rebuilt
Supply side fuel line replaced
TPS and other sensors appear to be good based on diag mode readouts
Cleaning, so much cleaning of everything...

And yes, the ground is solid.

[Paul_E_D]

I thought you just found a bad injector? I understand that the TPS were prone to failure on these bikes. Might be worth finding one you can test for comparison.

[Kurlon]

One injector did fail, and has been swapped. (Glad I got a spare set!) I've got a second complete throttle body rack from an 05, didn't use it 'cause I didn't want the larger TBs, but it's got a TPS. I'll try swapping it in.

[RyanNicholson]

I'm by no means a mechanical expert but I know the coils tend to shit the bed on those... a common issue as I recently learned in another thread on here. I had a few go on the 2nd gen R6's I've had. I also ran into issues with a secondary valve actuator after a particular bad crash that left me with similar symptoms to what you're describing. Shame you can't really load test it, as I was losing major power higher up in the revs because of it, which made diagnosing pretty easy.

[Kurlon]

No secondary valves on my machine that I'm aware of, those didn't show up until 06 on the 3rd gen IIRC?

Swapped TPS, no change in behavior. I need to track down a later service manual as the TPS adjust procedure is giving bogus results. Using the diag mode on the dash I can dial it right in. Using a multimeter as prescribed I'm seeing 4v where I'm supposed to see .6v, wee bit off there. I suspect a typo. Resistances check out on both TPS.

[RyanNicholson]

No secondary valves on my machine that I'm aware of, those didn't show up until 06 on the 3rd gen IIRC?

You might be right... this was 10 years ago or so, so I might be mixing up issues/memories.

[Paul_E_D]

TPS settings are usually around .4 to .7V 4V is whacked.

[Kurlon]

TPS settings are usually around .4 to .7V 4V is whacked.

Yeah, and to make it fun the only way to test is jam test probes into the harness and I'm thinking they're crossing in there or something. PC3's voltage reading for the TPS is what I'd expect, and as noted the bike's diag mode shows valid values so I'm ignoring the voltage test until I can make a clean test harness.

[Kurlon]

Plan C is to throw an expert at the bike and see what happens. Suggestions on who to take it to?

[loudbeard]

Plan C is to throw an expert at the bike and see what happens. Suggestions on who to take it to?

Oh man. Whoever it is they're *definitely* going to charge you a higher labor rate. You'd be better off to walk in somewhere and just say "my bike don't run good."


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[Kurlon]

I don't want to pay a regular shop to play "doctor" on the bike for days on end while flipping through the service manual's trouble shooting guide. I've got that covered. I wanna pay a tuner with experience and fully expect that to not come cheaply.

[loudbeard]

Don't take yourself so seriously. This should have been the most obvious joke possible, don't tell me you've never seen this.

[Pigman]

Scott at SVM....would prob be your best bet

[Kurlon]

Don't take yourself so seriously. This should have been the most obvious joke possible, don't tell me you've never seen this.

Hah, yeah, I think I've been the cause of that sign being posted in some shops.

[Kurlon]

And, just to make sure I'm not crazy, slide stops pulled, PC3 pulled, 6k RPM and she'll climb no further at WFO. Ease it up via partial throttle past the dead zone and she'll scream.

Anyone need 2nd gen R6 parts?

[Tekime]

If it ran fine, was then wrecked, and then sat for a long time, I'd be checking every line, vacuum line, breather, etc to make sure something wasn't damaged, knocked loose, put back in the wrong place, etc. From what tiny bit I've heard about the R6 the TPS can be a bitch to dial in even if it's good, I have no idea how to set it up though.

So basically I have nothing to add but hey, it's the Internet. Hope you get it fixed it up man! Reminds me of my first Jetta waaaayy before I started with bikes, spent a year and a half with similar issues, changed a hundred things, turned out to be a stupid vacuum line.

[TIMMYDUCK]

And, just to make sure I'm not crazy, slide stops pulled, PC3 pulled, 6k RPM and she'll climb no further at WFO. Ease it up via partial throttle past the dead zone and she'll scream.

Anyone need 2nd gen R6 parts?

Perhaps the fuel pump is on it's the way out or the fuel filter is partially clogged ?

[Kurlon]

I rebuilt the fuel pump, and cleaned the pump foot mesh. If it was on the way out I would expect the bike to fall on it's face and not be able to be coaxed up past 6k RPM?

Tekime - That's what I've been doing, I've had it torn down to just the motor hanging in the frame and have re-laid down the wiring harness and all plumbing. EFI sucks BTW, so many hoses and wires and hoses and wires... my FZR is so simple in comparison.

[Kurlon]

So, apparently the answer was: Run it in open practice. Running like a top now, weird hesitation/stumble never showed up on track and now it won't do it on the stands either.

Even scarier, all bikes in my possession are currently running correctly.