Superduke 08 dies when rolling of throttle at high revs

Post 1 by b0bl00i, 22 May 2009, 13:16

Hi lads and ladies.

My darling is not feeling well. Although this problem happens at random and is not easy to replicate.

When i accelerate as hard as i gets, full throttle on 2nd or third reaching almost rev limiter, i roll of throttle to begin slow down, using engine brake.. the bike dies sometimes which results in the back wheel locking up badly Nice, but not very safe...

I sometimes get the bike to start immediately using the stater engine but sometimes is takes up to 5-6 seconds to get her going.. What could cause this behavior? The Mechanic didn't have a clue and didn't take me very seriously i believe.

Have you guys experience it?

Post 2 by smackman, 22 May 2009, 14:02

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Post 3 by Pig Benis, 22 May 2009, 14:38

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Post 4 by cjc, 22 May 2009, 18:05

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Post 5 by b0bl00i, 23 May 2009, 07:47

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Post 6 by b0bl00i, 23 May 2009, 07:49

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Post 7 by overthetop.ca, 23 May 2009, 13:23

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did you ever find out what the problem was/is ? I seem to be having the same problem right now .

Post 8 by Zenbiker, 23 May 2009, 21:29

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Post 9 by overthetop.ca, 23 May 2009, 23:24

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full tank of gas,couple of back fires , but not all the time ? no kinky lines, and filter is good? akra map with akras ? no alarm.

Post 10 by Zenbiker, 24 May 2009, 11:39

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Hmmm. The fact that it occurs after maximum fuel demand is interesting; I'm running the same setup (Akra map, Akras, but also a PCIII). Best guess: sick fuel pump, ECU glitch not turning fuel back on after closing throttle, bad TPS, loose ECU connectors.

To follow on a stream of consciousness; engine requires max fuel flow under WOT; then goes dead lean (20:1 or higher) on closed throttle. Plugs still firing on every cycle. Open the throttle back up, ECU kicks pump back in, takes a few moments for injectors to repressurize and send fuel to intake stream, intake to hit chamber, combustion to occur (snatch). Why the delay; on the fuel side, lack of fuel in the lines/cavitation at the pump=delayed delivery; on the electronics side, something affected by physical/electronic demands - weak plugs, weak coils (ahhhh, maybe not so much, I'd expect them to crap under WOT); engine still turning under own momentum, but then dies and locks up?

Whiskey Tango Foxtrot?

Motor is still turning even with throttle closed. So why does it lock up?
No stutter, just "takes a while to catch" when throttle is applied or stalls and locks up rear wheel .

Ahhh, I can't put a finger on it, 'specially twixt the electronics and fuel delivery side of it. Anybody else have another angle? Like a tipover kill switch? Finger of God pointing down and punishing you for Hooliganism? (Actually, I'm more into the Hand of Satan just being a bastard view, with the Hand of God keepin' yer ass in one piece, just sayin...)

I dunno, guys, this is the best I can come up with on a Sunday morning with only one cuppa...

Or how about a clogged fuel tank vent? And for you Swedish riders, maybe some lutefisk in the tank? I mean, that could clog the works, to be sure...

Post 11 by Zenbiker, 24 May 2009, 11:46

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Post 12 by b0bl00i, 25 May 2009, 13:45

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Post 13 by Zenbiker, 25 May 2009, 20:19

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Post 14 by overthetop.ca, 26 May 2009, 01:40

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Post 15 by Motohooligan, 26 May 2009, 02:05

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Post 16 by Zenbiker, 26 May 2009, 11:20

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Post 17 by Lowrance, 26 May 2009, 12:17

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Post 18 by overthetop.ca, 26 May 2009, 12:51

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Post 19 by smoky, 26 May 2009, 14:08

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this has happened to me maybe 5 times total, and not in a while, so i kind of gave up on it, but at one point i was going to add some fuel in the PC map at "0" throttle and from 2000 to maybe 4000 RPM. not sure if PC would override the ECU cutting fuel off at closed throttle...
as it has not happened in a while, i did not have a chance to test this, but if one of you guys has a PC, maybe that would be worth a try? simple to do, just as easy to reverse ...

Post 20 by Zenbiker, 26 May 2009, 16:21

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Throttle position sensor, throttle position sensor, throttle position sensor...
On the PCIII you can set zero throttle position; will have to dig up that procedure , its on another computer.

Post 21 by Zenbiker, 26 May 2009, 16:39

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Have experienced the same thing as b0bl00i described multiple times, each time when I'm accelarating hard out of a corner. Very anxious to find the cause of the problem as I don't like it that much when the back wheel is locking up.

Post 22 by b0bl00i, 26 May 2009, 19:43

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Post 23 by b0bl00i, 27 May 2009, 09:35

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Post 24 by overthetop.ca, 27 May 2009, 09:36

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Post 25 by Zenbiker, 29 May 2009, 17:33

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Keep us up to speed, OTT; from the sounds of it, I expect my bike to do this next.

ZenBikers List Of Reasons A SuperDuke Would Stall:

1) Bad Clutch Switch (brilliantly deduced by MotoHooligan)
2) Restricted Intake - can't breath, can't run
3) Restricted Fuel Delivery/fuel starvation - can't eat, can't run, can take the form of electrical/electronic gremlin and/or stupid stuff like kinked fuel line, clogged fuel line (see: Lutefisk), clogged tank vent building up vacuum as fuel pump sucks out the fuel, and other things that I can't think of.
4) TPS sensors out of calibration sending ECU over the edge
5) Girlfriend is from Jamaica and practices Santaria and has placed blood curse on you for a perceived or actual infidelity.
6) Ignition component failing - seems to happen after heavy duty cycle
7) Loose electrical connector - why only after hard acceleration

now transitioning to stream of consciousness
Seems to have something to do with hard acceleration. What happens at WOT? Fuel pump demand spins up, plugs fire more frequently, engine rpm climbs, oil pressure rises (hopefully), electronics heat up from resistance/heat possibly leading to temporarily open condition, fuel tank temporarily pulls vacuum if demand for fuel volume exceeds vent capacity; let off throttle, bike goes into lean mode for pollution control, ECU cuts fuel to the injectors, bike is hot, tight parts sieze momentarily.

OK, question: you're on the throttle hard on a hot bike. You get off the throttle and the bike stalls. What effect does opening the throttle have? How do you have to restart the bike? Does it ever restart as in a bump start after the rear tyre locks up, or do you have to either by necessity or desire have to come to a stop and hit the starter button? Do you have to cycle the ignition?