98Gixxer750 powerloss

bcgixxer · 09-03-2007, 11:19 PM

Ok, so i have been having this problem for a month now and cant figure it out, after my bike warms up when i accelerate i get a big power loss around 5000 rpms. at first i thought it was bad gas, i always put 92 octane or more in my tanks. i even put some dry gas in with one tank fill up to make sure there was no water or anything. Back to the problem when the bike starts to lose power at 5000 it shudders and jolts between power and no power, however if i can get the bike past 6000 rpms it usually runs pretty good after that. this is really beginning to ruin riding for me. I dont have much experience with bikes i traditionally work on jeeps but this is my first bike and i dont want it to ruin my experience. any help would be good

Redstar11 · 09-03-2007, 11:22 PM

Does the problem always occur? Will it do it revving freely in neutral?

Veefer97 · 09-04-2007, 07:32 AM

Check the carb slides for freedom of movement. The midrange is controled by the slide needles. You may want to put in one shim under each needle and see if the problem changes. This will richen the midrange. If the needles are aftermarket they will have grooves. Moving the clip one groove is a large adjustment, the shim is exactly 1/2 the groove adjustment.

bcgixxer · 09-04-2007, 10:46 AM

Quote:

Originally Posted by Redstar11

Does the problem always occur? Will it do it revving freely in neutral?

yes it revs freely in neutral. it occurs after my bike has warmed up mainly, like if i take it out after starting it not giving it to much time to warm up it runs great at all rpms and there is plenty of power but after it warms up it starts the whole shuddering thing.

as for checking the slide needles, it is hard for me to work on my bike all my tools are located an hour from me at my parents house, and unfortunately working the parking lot of my apartment complex is crap cause I wouldn't have time to completely take it apart before having to put it back together. it might be a week or so before i can do that, but it should give me time to look at the service manual.

Redstar11 · 09-04-2007, 11:13 AM

I would definitely start with a carburetion problem. In addition to what Veefer recommended, try taping off a 1/3 section of the carburetors to restrict airflow. That will let you see how the bike is affected by fueling mixture changes. If it starts to run better, then you can surmise you have a lean running problem, or lean misfire. You can then take out the airbox and tape, to see if it runs better by leaning out the mixture.

bcgixxer · 09-04-2007, 11:53 AM

ok thanks guys i will try these things and if they dont improve ill be right back on here!!!!! this is a big help

Veefer97 · 09-04-2007, 12:28 PM

This is tricky but you can apply a bit of choke (enrichment) at the affected RPM. If the bike runs better then it is a midrange lean condition. Do it in a parking lot with no trafic.

768-Ryda · 09-04-2007, 10:50 PM

i think in 98 suzuki made the 750's fuel injected, what mods do u have done to the bike, also take a look at your fuel pump and check to see if the air filter needs to be cleaned are replaced, also run u some fuel injector cleaner thru your fuel system to see that will help and also check to see if plugs are needin changed

Redstar11 · 09-05-2007, 01:40 PM

98's are fuel injected. I was thinking of a 600 for some reason.

Veefer97 · 09-05-2007, 03:50 PM

Sorry, I was thinking carbs

Redstar11 · 09-05-2007, 05:48 PM

Pull out your spark plugs, and see if them indicate a problem in a particular cylinder.

bcgixxer · 09-27-2007, 10:05 PM

ok guys sorry it has been a long time on this one, but i have been busy with school.

ok 98's do have FI, so i was looking at my throttle body everything seems to be tight no loose screws any thing, no slack in throttle or anything. pulled the plugs they didnt seem to bad, a lil outside the specified gap range so i replaced them while i had them out, change the air filter, looked over the engine everythign seems to be right on it, but i am still getting the sudden power loss. the thing is it is usually around 5 or 6 thousand rpms but it is completely random, i dont know when it is going to do it, also it seems like the bike doesnt do it as much when it is cold out but i can defer there too.

please any more advice. love riding hate this.

Redstar11 · 09-28-2007, 10:41 AM

Check stuff like your sidestand switch. I have seen vibrations at certain RPMS cause the interlock switch to cut in and out, causing power loss.

RayOSV · 09-28-2007, 12:00 PM

Quote:

Originally Posted by Redstar11

Check stuff like your sidestand switch. I have seen vibrations at certain RPMS cause the interlock switch to cut in and out, causing power loss.

+1 to this. If you're getting random, complete engine cut-out, it sounds electrical with a mechanical/vibration cause. Does anything else electrical cut out at the same time? Gauges, lights, etc.?

Check the kill switch as well for corroded or loose terminals.

bcgixxer · 09-28-2007, 12:20 PM

you know i have been having a problem with my neutral light not coming on when i put it in neutral, and sometimes i have to push the side stand switch in order for the neutral light to come onn in order to start it. good tips ill look today thanks guys.