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Discussion Starter · #1 ·
Hello, My name is chris and I own a 87 Kawasaki KX500, that has a couple of problems. One problem that seems to happen more when I first start the bike is that after I start the bike (which the bike starts good) is sometime the motor starts to race (RPMs gain alot) like if I opened it up wide open, for know reason. It is like I turned off the gas and let the carp. lean out. But the bike will die after about 5 sec.s or so of that. And after I restart the bike it will run good. And for some reason when the bikes RPMs are that high the kill switch doesn't work. But the kill switch works ok at idle, and at other RPMs. This as also happend when I am riding it, and it does the same thing it will die after a couple of sec.s. Sometimes it will run though 2 tanks and never happen. I have replaced the kill switch and the bike still will not turn off with it at that high RPM's. I am thinking that the problem as some thing to do with fuel not air for say, I am thinking since the bike does die after a couple of sec.s that is because maybe the fuel as been sucked out of the carp. with know more fuel being suppied to it, like if some one turned off the gas from the tank. I have check the carp. out. I have cleaned the peck-cok screen.I am thing about replacing the floats and the valve that allows the fuel into the bowl. My next problem is not really a big problem, but one that I would like to solve. Ever time I give the bike gas and raise the RPMs, the RPMs gain quik, but when I release the gas the RPM's drop almost to a idle quik but right before it gets to the idle it stops dropping so quik as it was. If you can under stand that. I have watch the carb. slide go up and then drops right back down, with no problem. I was hoping to see the slide slow down right before it should but it didn't. So any body with any ideas please reply.

In a summury I have three problems.
1)Bike will open up wide open for about 5 sec.s or so
2)Bike can't be killed with the kill switch at them high RPMs.
3)Bike does not come back down from a idle as quik as it went up.

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411 Posts
Although you have used some terminology that I'm not familiar with it sounds like you have an air leak. On older bikes the rubber intake boot can dry out and crack. I've also seen old 'carps' that have worn out and air leaks in around the slide. That's for problems #1 & 2.
Problem #3. If the bike is running a tad lean it may be dieseling at high rpm and that's why you can't shut it down with the kill switch. The spark plug or bits of carbon or crap in the combustion chamber get hot enough to ignite the fuel mixture independant of the plug firing. To test this pull the spark plug lead off at an rpm when the kill switch isn't doing it's job. If the engine quits then you have an electrical problem. If it keeps running, then it's dieseling. Maybe you can try a colder sparkplug. Either way the shot of adrenaline from grabbing the live wire is worth the effort.
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