Maintenance & Technical > KX250 / KX125
Getting the jet needle out of the throttle valve?
500HORZ:
Hey Friartuck,
Do you know the stock needle part number, and what is the slock slide number - it's on the bottom of the slide near where the needle comes thru - 6, and 7 are common.
I've got an 86 kx500 and a 99 PWK air Striker - it has a #7 slide and CGH needle, 50 pilot (may be a tad lean) seems to be working fine. I plan to move to a 52 pilot and want to know what needle works best in your experience.
Also, have you done plug chops on the main jets, they seem a tad lean to me, I am running a 175 and the plug looks good, maybe a touch rich, ...
thx.
Friar-Tuck:
500,
Are you asking for a 99 500 PWK ? Stock OEM is #7 slide,60pilot and a N82M 3rd clip. I have been told that a CGG is a sudco/keihin replacement #. I did not call sudco to confirm this however if you need one they can give you verification or another #.
I have a #7 slide in my 500.
98% of the guys run the stock N82M and like it. There is alot to be said about what kind of riding you do, how you ride, elevation and weather.
I have to tell you right off I am a chronic tinkerer.
The bike ran great with a 170 main 2nd clip and a 55 pilot 55-60 degrees between 3500 & 4000'
However I had to ride consistantly faster than I was comfy with, and constantly shifting to keep the bike in what I felt was a good rpm range.....Soo... I started moving things around. gearing, and then jetting.
Some things to consider 90% of our riding is singletrack, hills and skidder trails. 3500' to probably 7000'.
The fire roads we have here your lucky to get it WOT in third let alone 5th, and even the power lines are you are lucky to hit 3rd. Yes my jetting is lean by any standard.
However I am Old, Slow, and have no business riding this bike... But I love it. I can crack the throttle and pop up the front end at will and I'm about 240-245#'s. Lug it down in 1st now and I can almost idle along. Well, if I turn the Idle up a few turns I'm sure I could.
(I also have a bp7es plug in right now to see how that looks next ride, the 8 was rather wet last time out)
If someone at or near sea level on a 70deg day tried to run this set up out in the flats the wouldn't get very far before the bike gave up.
I also have 13/51 gearing and it's actually the first time I had the bike in 5th without running along the highway. I can now roll along at 10-15 mph through the trails at about 1/4 throttle. Where as prior to this I was constantly shifting 1 2nd and sometimes 3rd.
My best friend had a 99 500 and the only difference between his and my set up was he runs a 168 main and 14/48 gearing. And he rides a heck of alot harder than I do.
I hate to keep refering to my old CR but I had the darn thing dialed in great for myself. No plug fouling no spooge and the inside of the silencer was coffee ground brown.
I still am working to that on my KX and am getting close.
mustangfury:
Ok i got the new main jets and put the 158 in.
I am now running:
Main jet 158
Clip position 3rd
Throttle Valve #5
Pilot Jet 52
Fuel mixture 40:1
Oil Bel Ray H1R
I rode the bike around in my 1/4 acre yard for about 10 minutes and kept it between 1/4 and 1/2 throttle most of the time with 3/4 throttle for a quick dash down my sidewalk here and there. The cylinder got hot enough to where i could feel it was getting warm. It did not get super hot or anything like when i am going WOT but it just got warmed up.
At first the bike spat oil just the same but I definitely noticed a difference as the bike was warming up. At the hottest point it was still spitting a little. Once i got it up to a so so temp I shut her down and wiped up all the oil so i could start looking while it was hot. I started her up and gave her a short ride. There was not a lot on the rear fender, almost none on the swing arm, a few small drops on the rear caliper, and just a little accumulating at the back tip of the silencer. After she cooled down I pulled the plug and attached pictures show what it looked like.
I know it was not completely hot yet but I don't go up to my uncles farm often and it is an hour and a half away. My girlfriend has a 30 acre farm though and she is only about 35 minutes away so i am hoping to go up there soon to get the bike nice and hot (like tomorrow or sometime this weekend). I don't have many places to ride where i live, so I like to take advantage of a big field to do tuning when i can. I was just wondering what would be the next step to take depending on what the plug looks like after I ride her some more, and should i rider her at full throttle and get her up to a full ride temp for a bit seeing there is still oil on the plug?
Thanks. let me know what you think. Your help has been great!
Friar-Tuck:
Hey Stang,
Sounds like things are moving in the right direction. By the wet, dark oily appearance of the plug, You still probably have the oil that was previously in the crankcase working it's way through the engine. It will take some time to get the whole system cleaned out.
Here is an article worth reading through on plugs: http://www.strappe.com/plugs.html
The same guy on oil pre-mix ratio: http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf
If you can find the time to read through these two articles it would be great.
I misunderstood about the pre-mix ratio. I thought you wanted to run 32:1. that is what the FMF & Pro-Circuit bikes were running when they put out the jetting recommendations. It is up to you as to what you want to run, just stick to one ratio until we get the bike sorted out. After you are happy with the state of tune, then you will at least have a baseline to work off of. Then we can pursue any other changes you would like.
The next time you get out to the farm to do some riding, I would repeat what you did around the house and get the bike up to operating temp. Run her up to 3/4 throttle for a bit and check your plug again.
Make any pertinent notes we need to address, like "bike seems to bog at half throttle" or "doesn't pick up very clean" "throttle response in the mid range is slow" .etc.
By repeating the warm up and plug check you will verify we aren't hurting your bike and cleaning it out.
Next, =)
Is there a stretch of road or field where you can run the bike wide open 30 seconds to a minute?
What we are gonna try to do is after you got her up to temp is a plug chop. Run the bike wide open for 30 sec to a minute and kill the engine. Hit the kill switch and pull in the clutch.
What we want to accomplish is see what the bike is doing wide open. By not letting the bike Idle or decelerate using the engine compression we won't wash off the evidence on the plug.
Tuck\o/
mustangfury:
I do want to run 32:1 but I still had the 40:1 in the tank at the time. when i take it out to the farm i will put the 32:1 back in it.
I do have a section where i can run it wide open for 30 seconds. I will be going to my girlfriends today so I should be able to try it out.
The bike overall ran a lot better yesterday when i tested it. The throttle was a lot more responsive through every powerband. This is definitely helping.
Also, the weather conditions yesterday were 60 degrees, no precipitation, low humidity.
The forecast for today is 69 degrees, no precipitation, 30% humidity.
How should i set the idle? Should idle be set as low as possible but steady, high as possible, or in the middle? I have the air screw at 1.5 turns out like stated and that works good. I was just wondering where to set the idle screw at.
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