KX500 engine races...

[ben]

One thing my 2001 KX500 just started doing is when I start it the engine races, and then I quickly turn the choke off, and it still races, but not quite as much.  Once it gets warmed up, it will eventually idle, but when you blip the throttle it races a bit and takes a while to settle down to an idle.  I first thought it might have an air leak, but with the engine running, I sprayed brake cleaner on the cylinder base gasket and head gasket, and the engine RPM didn't change at all.  I popped off the plastic flywheel cover and sprayed brake cleaner in there to see if it was sucking air through the crank seal, and once again the engine RPM didn't change.  
 
The next thing I am going to do is to take off the carb and clean it, as well as inspect the reeds.
 
Any other ideas?

Thanks!

--Ben

[mikesmith]

I would also guess an air leak,maybe you should pressure test it and you soap and water to check for leaks.The slide isnt sticking is it?

[ben]

Thanks for the response.  I'm pretty sure the slide isn't sticking.  I took the carb off last night and cleaned it thoroughly, and I checked the reeds and they looked fine.  I put everything back together and it is still doing the same thing.  I tried playing around with the idle screw and it doesn't seem to change the idle at all.  I'm thinking I have an air leak, I just don't know where.  I'm a little disappointed too - this KX500 has very little time on it.

Anyways, how do I go about pressure testing it using soap and water?

Any other ideas?

Thanks!

--Ben

[Rick]

How is your plug reading?

[mikesmith]

You would have to block off the intake and exahust air tight and then pump in like 7psi,then spray liquid dish soap dilluted with water on any areas that could leak,like gaskets and seals to find any bubbles from a leak.But before you do that how "little" time is on the bike and have you just recently done any work on it like a top end ect?I think Rick wants to know hows your jetting and is the air screw set right?

[ben]

Well, I took an interesting approach to solving this problem.  Last week I took off the carb and cleaned it real well, making sure the pilot jet was not clogged.  Everything looked okay but when I bolted it back together, and started it up, the engine continued to race.

Rick, the plug is black, but I know it is running lean - I just don't let it run long enough to turn the plug a light tan or white.

So on Saturday I did what any KX500 owner would do, I went out and bought another one!  I found a 99 that was in VGC and had some nice extras with it, both on and off the bike.  I got it for $1575, which I thought was pretty good price.

I took the carb of the 99 and put it on the 01, just to make sure the carb wasn't the problem.  The 01 engine still raced with the 99 carb.  I guess it has to be an air leak somewhere, so I am going to try a pressure test in the near future.

So now I have a one KX500 that runs great, and I can take my time fixing the other one, and still get my KX500 rush once or twice a week.

Is there some sort of open bike support group I could attend? This is my 6th KX500 over the past 10 years.  "Hello, my name is Ben, and yes, I have an open bike problem..."

--Ben
2003 Yamaha YZ450
2001 Kawasaki KX500
1999 Kawasaki KX500

[Folke]

I think you have to change seal-oil in the crank