Suzuki GSX-R Motorcycle Forums Gixxer.com banner

05 gsxr600, low rpm, lack of power

22K views 32 replies 11 participants last post by  TheGeek  
#1 · (Edited)
So i just bought a bike and now it suddenly has this problem

when i'm trying to accel under 3k rpm it hesitates, like it miss fires or something
but once its ovr 3k rpm it doesn't stutter anymore and rides fine

so this has become annoying as i hv ot rev it up before i can take off from a light

the valves do sound kind of noisy but it only has 14,100kms on it

the previous owner had it since new and rarely rode it

probably has been sitting a while

so my question is, should i go ahead and give it a 12k km tune up as he probably didn't and expect that hte problem will be solved or

is there something else going on?

also, i only got like 190 kms to the last tank

seems kinda low as my old 99 cbr600 got at least 300/tank with 50/50, ripping it/chillin it

it has a D and D slip on
 
#2 ·
When it's in neutral idling, what is the RPM? It also could need spark plugs if it's been sitting a while. As far as your mileage, 190 Kms which is around 120 miles for me, seems pretty normal if you are riding a little hard. 300 kms or 185 miles is unheard of. The best I've had was around 140-150 miles.
 
#5 ·
i'm pretty sure you have to find where the fuel pump pumps fuel right before injectors

and put the line into a cup or watter bottle

turn key which will activate the fuel pump to pressurize, basically if it pump a decent amt of fuel it's fine, if it's barely noticeable then its not pumping enough

but why would the fuel pump work properly at high rpms and not low rpms?

**************** my bike idles at like 1000-1200 rpm
 
#8 ·
At low RPM the IAP, AP, throttle balance, and TPS are the critical inputs.

Check your vacuum lines to the IAP sensor and check the TPS calibration. Sync the throttle bodies next, and then test the pressure sensors (which is difficult).

But, it could also be poor fuel atomization from dirty injectors or even poor compression.
 
#11 ·
The atmospheric sensor has no line on it... it's just open to the atmosphere. The IAP sensor is the same thing, but is connected with lines to sample the pressure inside the intakes. Take the differential between the two and compound it with the air temp (IAT) and you know exactly how much air is going into the engine, and therefore how much fuel needs to be sprayed.

The amount of fuel is calculated off a given pressure and known flow rate at that pressure for the injectors.

Screw up any one piece of the system and your mix will be off. The engine is most sensitive to this at low RPM.
 
#26 ·
AP - atmospheric pressure. Located under the drivers seat next to the fuse box

IAT - Intake Air Temperature. Gold colored probe inside the airbox. Connector is green on the bottom right side of the airbox

IAP - Intake Air Pressue. Looks just like the AP, but mounted under the airbox on the back right bottom corner. Has a hose leading down that tees off to each of the inake runners.
 
#32 ·
Geek, would any one of these sensors throw a fault code?, i have 2004 gsxr600 and it is also hesitating and loading up at the bottom coming off a stop and then seems to clear up in the higher rpm's.bike has 6800 miles on it.i read one of your posts and put it in diag. mode and i had no faults stored "_c00" looks like tps was off, i tried to set it tothe middle spot but it would not respond at first, then i went all the way clockwise with it to get a base and i observed the idle, it seemed a bit better but when i rode it the bike fell on its face off a stop and then it seemed a little better after around 3-4k. when i got back to my garage i checked the tps setting and it read"-c00" so it looks like its in the right spot now but i doubt it. its still tweeked all the way to the forward most spot. i will remove it and sweep it with a multimeter"dvom" and see if the signal breaks up.maybe a bad tps, but i have no fault?? would it log a fault,and how about the other sensors for iap,iat and ap? would they log faults? thanks
 
#27 ·
^ check everything the geek is talking about. If everything is fine, check your battery voltage. If your charging system is malfunctioning it could cause a weak spark and hinder combustion causing it not to burn all of the fuel available. Not saying this is your problem, just something easy to check.
 
#33 ·
All of them would in some cases. But they don't know if their getting inaccurate results. If the sensor has an electrical problem, they will always throw a code. But if you disconnect the line from the IAP sensor, it just thinks the engine is getting a lot of air and the bike will go super rich. I've even heard of debris being in the barb on the IAP and causing problems. They're just hard to test.