This is highly technical and you have done a great job to look around correctly. As you have inferred the fault seems to be fuel starving at the highest point when it is required to PUMP into where the shortage of fuel seems to starve off the engine.
Seems that the settings for fuel flow must be altered to suit your requirement, the change of throttle body did make a change suggesting that flow was better than the first one.
The low fuel pumping--- 1040 instead of 1200+- is also a point to consider. If the fuel pump calibration can be increased this might help.
Otherwise I think you are doing the right thing , start with the fuel pump bring up the pressure to exceed 1200.
Good day.
Hi.
before checking the fuel pump further, i must ask if you have changed the air filter and fuel filters.
i have had MANY ocassions where these simple filters have been overlooked and they can easily cause the symptoms you are describing, even when they look perfectly clear.
also change the spark plugs as these can also cause these symptoms.
i will be honest and say that a 10% drop in the fuel flow should not prevent you being able to wheelie at 5k in 1st and i think the problem does lie elsewhere.
filters are the first suspect, then plugs.
after doing these it would also be worth taking the bike on a 50-60 mile run to get everything up to temperature and burn any soot etc from the exhaust.
if your other bike is identical, it may be worth swapping the fuel pumps over and seeing if you get an increase in power, or a drop in power on the other bike.
i think after that you would have two choices. the first (and recommended) being to get a computer diagnotsic check done on the bike to find out if there are any faulty sensors etc on the bike and sort out as needed.
the other would be to swap components and sensors with the other bike one at a time until you find a component that affects the performance of the machine.
i hope this advice helps, but please feel free to ask again if you have any further questions
hi.
if it was only the higher revs that were a problem, then i would think about a faulty pump not feeding enough fuel to match demand. a quick burst of power at low revs should not be a problem though in that case as there should still be enough fuel in the lines for a quick burst before the pump lags behind.
it may be worth trying to find what pressure the pump should run at and have that checked.
i cannot find any figures for running pressure of the pump at the minute, but if the pressure is low then that may cause some of the issues you have mentioned.
i think that the cable adjustments on the exup motor and valve need to be checked first though, as that can make a HUGE difference in performance.
you are obviously in the right area for the cable length as it starts smoothly and runs quite well, but to get the top end power, you could try adjusting the cable by about 1/4mm at a time, until you get no more improvement. if the first few adjustments make it worse, adjust the cable in the other direction. if 4 or 5mm in either direction do not make a difference, then return the cable to its original position.
it is difficult to give lengths on cable adjustments for those units, as there is quite a wide variation of lengths, depending on exactly when you want the valve to open, either for full on power, or for a power/economy compromise. most of that is down to your preference when you are using the machine.
it cannot be too far out or the computer would show a fault as well, but this is the area that i would be checking first.
good luck
hi.
not really worried about the pump. pressure test would have been more reassurance than anything else. the cable length on the EXUP unit is far more likely to cause those problems, as it also affect the position of the valve. i have found this link which should help. I found it quite useful myself. i am not sure what bike it is on, but it shows how to set the valve up properly, and explains quite clearly how they workhttp://www.cartestsoftware.com/fz1/exupm...
hope this helps
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If hte fuel pump is that out of specification then I would recommend replacing it. That far out of range would cause something like that to happen.
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2002 Suzuki GSXR 1000 fuel pump puts out 1,040 ml fuel in 30 seconds. Manual specs is: "approximately 1200 ml in 30 seconds".
Is mine out of spec enough to cause the bike to sputter at about 7K RPM and not have the normal strong pull when you punch it at the lower RPM's.
Brand new air filter and plugs.
The high speed fuel filter is a cartridge that is built into the pump, not a simple inline filter. It can be replaced but costs more than a good used pump. The manual does say "approximately 1200 ml", so that is way I was sceptical that 1,040 ml would be a problem.
The other bike is 2K miles away, in another state. It has 28K miles on it and runs scarey awesome.
The bike has an internal computer that does not read any error codes, for what that is worth.
When I got the bike, used, a few months ago the Fi light was on and the code was for the EXUP valve. The exup motor did make grinding noises and did not actuate the valve. I replaced that servo motor, it seems to work now and the error code went away. I wasn't sure about the cable adjustments on the servo motor, so just kind of guessed on that.
The manual has specs for pump pressure but it recommends special tools (lines) that keeps the connection to the injectors so it is in series with the whole system.
So you are changing your mind a bit about the fuel pump as possible culprit ?
Tom
That is funny because it was the 1st thing I wanted the independent mecahanic to check months ago.
I will mess with it.
It sounds like, as long as it opens all the way it will run good at high revs.
I'll let you know what happens for future reference.
Tom
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