KX500 WOT ISSUES

[jforbesautotech]

Hi, I have a 1995 KX500 that I bought from a buddy and needed cylinder work so I had a sleeve put in the cylinder. I got the bike running the other day and it runs good other than WOT, it just falls on its face at WOT.  I would just like to know what all would cause this problem. I am at about 3500 feet and the main jet is 168, dont know if it is starving for fuel at WOT or what. Any help would be appreciated. Thanks

[KXcam22]

Does it eventually die at WOT or instantly.  Could be many things. What have you checked so far? Cam.

[jforbesautotech]

It is pretty much instantly when you get past 3/4 throttle it just doesnt have anything and you can hear the motor struggling when you hit WOT. I havent checked a whole lot because I dont really know what to look for. I checked the reeds when I put it back together and they looked pretty good no cracks or anything and also checked the main jet and it is a 168. I just dont know where too look for the problem. I thought about putting a reed spacer and maybe new reeds but I dont know if that would do anything or not. Thanks

[cbxracer30]

Did the bike run before the resleeving? If not, how long did it sit? Whats the plug look like ? Put a new one in cheap B8es then check it. Did you change the fuel ? New fuel will help , also clean the carb ,a carb with water or excess oil in the bottom will shut off like that when you go to WOT. Check the carb first then go from there.Keep us posted. CBX

[jforbesautotech]

The guy I got the bike from said that it ran good and it only sit for a few weeks until I got it. I changed the plug when I put it all back together and also changed the fuel and cleaned the carb. I done all of this prior to riding for first time. I am running amsoil saber professional at 32:1 ratio. Thanks

[cbxracer30]

At least pull the drain plug off the bottom of the carb and check for water its 17mm careful not to spill it till you can look and see if there is any water in it. I've never run amsoil. Hows the plug look now? white or black?CBX

[jforbesautotech]

Pulled the drain plug and no water, and the plug looks pretty black.

[dans89kx500]

The guy I got the bike from said that it ran good and it only sit for a few weeks until I got it. I changed the plug when I put it all back together and also changed the fuel and cleaned the carb. I done all of this prior to riding for first time. I am running amsoil saber professional at 32:1 ratio. Thanks

Thats tough. The line: "ran good, only sat for two weeks," sound very simular to my situation. Two years and thousand dollars later.

Daniel in Vacaville

[Polar-Bus]

Hi, I have a 1995 KX500 that I bought from a buddy and needed cylinder work so I had a sleeve put in the cylinder. I got the bike running the other day and it runs good other than WOT, it just falls on its face at WOT.  I would just like to know what all would cause this problem. I am at about 3500 feet and the main jet is 168, dont know if it is starving for fuel at WOT or what. Any help would be appreciated. Thanks

It could also be the KIPS timing is off. That will make a KX500 pull like a 250...

[jforbesautotech]

Is their any way to know if the kips timing is off without pulling the cylinder. They seem to be moving fine .

[cbxracer30]

Take the exhaust off and take the KIPS arm cover off, look up in the exhaust hole and pull out on the KIPS arm and watch to see if they open the whole way.CBX

[BDI]

When a bike falls on it's face like that the first thing you should do is get out of the throttle and stop riding it. The second thing you should do is jet it up just incase it is to lean on the main. If the bike is to lean it will burn up and cost a ton of money. If it's not to lean you will know because the jet change will not help and you will know to look for somthing else. If you start looking at other things first and it was just to lean the chances are you are going to burn the bike up before you figure it out. If it is falling on it's face do to being to lean you should go up three jet sizes all at once. Then if that fixes it you need to figure out why it was to lean.

[jforbesautotech]

I am going to have to check the kips valve again I think because when I got the cylinder back with the new sleeve the center valve would not go in right because it was hitting the sleeve. I thought I ground it enough so that it would work right but maybe I didnt compensate for the heating. If it is sticking at times could it be causing this problem or would I notice the power loss at all engine speeds?

[BDI]

If it is your kips it will just go flat and stop pulling. If it is jetting it will fall on it's face and basicaly quit running.You can try everything else but if it is to lean it is going to cost you a motor if you don't try richening it up first.

[BDI]

I guess I should add on this that if it is to lean that would indicate that you have another problem like a bad main seal (just for example) because it shouldn't be to lean with that jetting. If the bike has been modified extensively that would change things, my bike will fall on it's face with a 175 main.