Maintenance & Technical > KX500 Original
Jetting!!! Again and again and again!
KXcam22:
Kawadude,
If your interested we could probably start looking at the jetting on your bike. For a start it would be a big help if you could post your riding conditions, elevation, temp, humitiy etc, the jetting you started with, and the jetting you have now. Also inlcude the bike year, and the engine modifications you have made, pipe porting reed etc. Maybe a description of how the bike runs. When Gowen gets his new needles, I think he will have his sorted out pretty quick. It's very close. I am not possitive that his settings will work for you as is, but what we have learned should be a huge help. Let me know. Cam.
gowen:
Cam, I ordered a CGJ as they do not make a CGI. It will be here tomarrow and I will have an answere to you by Friday night, hopefully. I'm assuming this will do the trick.
I've decided I will never go according to paper again. Meaning, I will never jet my bike according to a FMF's spec page or the service manual. :-)
This is FMF's chart for my KX500.
170 Main, 62 Pilot, 2nd clip, & 1.5 on the air screw @ 32:1 50/50 pump/race fuel, Sea Level - 1500, and at 70 degrees.
This is what my KX is at now.
155 Main, 38 Pilot, 3rd clip, & 1.5 to 2.0 on the air screw @ 50:1 50/50 pump/race fuel, Sea Level and somewhere in the 70-80 degree mark.
Anyway, lets get Kawdude's KX fixed up.
gowen:
Cam, I came up with an idea, I will record my bike at 1 1/2 turns VS. 2 1/2 turns.
Note: 2 1/2 turns idles the best @ a 38 Pilot.
First Clip: 1 1/2 Turns. Just fired up let run for 10 minutes before clipping sounds:
All hits on the throttle are nothing more than 1/4th throttle, one 1/2 throttle hit, and then a small 1/8th hit later on in the clip.
It seems to only do it in the 1/4th range to the 1/2 range.
Second Clip: 2 1/2 turns on the air screw. Seems the same! It did not help it at all.
Let me know what you guys think.
http://www.matchmakerautoservices.com/kx500/oneandhalf.wav
http://www.matchmakerautoservices.com/kx500/twoandhalf.wav
You can click to listen or right click and click "Save Target As" and put it on your desktop and listen too.
EDIT: Cam, listening to the sound clips, I'm thinking it is out in the Clip position. According to Sudco's chart, the diameter controls mainly the idle to 1/4th. The clip is the 1/4th and up. and the diameter is the 1/2 and up. According to the sounds 1/4th and 1/2 are the main place for surging.
Also, it ONLY surges on the return to idle, it DOES not surge while using the gas.
kawdude:
The surges on mine are on the let off also. Are you just cranking and letting the throttle retun to zero. That sounds just like mine. The second sounds lean to me. Too lean...no idea!
gowen:
Kawdude, yes, I'm just chopping the throttle. Hit and let off. Here's the frustration:
I worked on it this evening. Starting with the needle. I got my CGJ in. Installed it, and it was the same, same surging. Soo, I decided to go back one to CGH, still surged. Went back to the stock needle... Still surged. I then decided that it was not the diameter. So, I installed the CGK I was using before. I then dropped the clip one to the 4th notch.Still surged.. Same as the recordings. All the same. I have yet to try choking the carb to see if that clears the surges. The only way I've cleared them is by richening it to NO idle.
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