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KX60 jetting, Idle screw doesnt work

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just bought a 96 kx 60.

it doesnt wanna go full throttle.

its either starving or getting to much gas

stock jetting is 30 pj 200 mj

right now the bike has a 30 pj and 175 mj

i plan on going back to stock and going from there...

besides the carbon build up, the plug is a little wet to, im thinking the float level is a little off..

another thing is that the idle screw doesnt really work at all.

and these bikes dont have air screws.

it seems like im running lean, rich, and my float levels off?

any suggestions?

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i already cleaned the pilot circuit,

if i lower the pilot jet, will it make the idle screw work?

and should i go to stock 200 mj or try a 185?

Edited by dylans503

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Call your local dealer and verify the stock main jet size. My nephew races in the 85 class and the biggest main jet I've had to run was a 145, and that was after adding a pipe, Vforce3 reed cage and LLLOOOOOTTTTTSSSS of porting. Your 200 Main jet seems really, really high to me,

Might take a look a this as well if your having to get into jetting issues.

http://www.dansmc.com/carbs2.htm

Let start there.

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Wow. Interesting.

Before we start please verify these things. Is the air cleaner clean? Do you have fresh plug in? Is th the plug gapped correctly? Do you have good gas in the tank mixed to the proper ratio? Are you sure you're mixing the gas the same way the previous owner did? ( in other words, you're not mixing at 32-to-1 and the previous owner was at 50-to-1).

Above all good? Okay then, next.

Well, you stated that the motor won't "clean out" or "run" out at WOT. Correct? Does this mean that you can't get on the bike and run it through the power band and the motor ever clean out? It always falls on its face?

If so, does it sound like a "boooog" or a "bla -bla-bla"? In other words, does the motor sound like it wants to wined out but cant (bog) or does it sound like it wants to fall on its face (bla-bla-bla)? Is there any popping or back firing? Popping is usually lean, back firing is usually rich. However, sometimes it's the other way. I know, it confusing, and it sucks.🤣

Lets confirm there are no air leaks. Start and run the motor around 1/4 throttle. Take some carburetor cleaner and spray it around the entire intake path. Start from the air cleaner boot, then around each side of the carburetor, then the reed-cage on the head, and then around the head and base of the cylinder . Please go ahead and take the cover off the magnetos and stray the cleaner towards the back of the stator/magnetos. the Does the motor rev up? If so, we have a air leak and we're running lean. If not, lets try something new.

If you've confirmed all the above to be good the I would take the carburetor out and clean it. Get some Chem-tool from any auto parts store (the one gallon, $20.00) and totally disassemble the carburetor. Make sure you take ALL the rubber and plastic parts out because the chem-tool will eat these parts. Soak them over night and clean them with soapy water and high pressure air the next day. Go ahead any buy new main and pilot jets ($12.00) Reassembly, reinstall, try again.

Again, lets start here.👍

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wow thanks for the write up!

lots of great info,

but ive already done all that (except for check for an air leak )

. soaked the carb and all, new plug, gas, and clean air filter.

the bike sounds really throaty when you rev it out, and it doesnt have that smooooth WHACK 2 stroke whinedy hit.

no popping or anything.

ive been using 40-1, which is what the owner ran.

when i first go it, it wouldnt really wanna get enough rpms to hit the next gear and it would just kinda chug along and wouldnt go into the power band, it would just rev high.

but after i went through it all its running alot better. just not tuned in yet.

only thing thats left is the jetting, and at stock pilot, and 25 main jet sizes leaner then stock, im thinking thats whats it.

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Our 60 runs fine with a 200 main, I don't recall what the pilot is off the top of my head, I'll check if you really need me to.

Oh, and you want 32:1 pre-mix, these things are known to self destruct. I'd go back to a 200 main and 32:1, unless you're running at really high elevation, then perhaps a 185-190 main is warranted.

Since your idle screw is hosed, check for anything else that's been messed up. Let me know if you need anything, we've got a carb with a missing float valve that as far as I know is otherwise complete.

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Agreed, I think the 32:1 would be a better mix, too. Those little 60's are worse than 85's when it comes to having no low end, OK mid, and rip your head off top end's. In other words, they produce no real house power until there running at 10,000 RPM+.

You stated it sound "throaty" and it seems to want to "rev out" a little uncontrollably and produce no real power at certain points of the power band, that defiantly sounding lean.

This is a little of a long shot but,.... We had a KTM 65 for a while and when the crank seal behind the magneto started going out it would lean out and acting the way you're describing. Hence, why I lead you to start check for leaks before jetting. Luckily, the KTM was such a P.O.S. that we didn't have to split the cased to fix this problem, just remove the magneto and pull the seal, then replace. Not sure on the KX, I think you would have to split the cases.

Anyway, was just trying to verify there were no other issues (air leaks) before you jumped in the "jetting boxing ring".

Was the previous owner racing the bike? You stated the pilot jet was leaner than stock. We do this too to get our younger riders to ride higher in the power band and to stay out of the lower throttle positions. Little harder on the top end but when you're training a younger racer to race it helps and I think it worth it. However, it does make the jetting more responsive (most of the time in a bad way) to temperatures changes. This will also create some of the idling issues you've described.

When you "blip" the throttle with the bike in neutral does the motor come right back to a idle speed or does it get caught in a higher RPM range and slowly come back down to an idle range? If so, your pilot is too lean. If you do the same and the motor drops below a idle speed then comes back up this is usually a rich condition at the pilot.

hope that help, bro!! Let us know how thinge are going!!

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when i blip the throttle it kinda does a combo of all 3, its hard to tell.

also, the plug thats in it is a br7hs or somethin, stock is br9eg i think

i put a br8es in.

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You really want to get the right plug in there. The 'h' would have the plug recessed 7mm which could create hot spots where the threads are exposed on the cyl. head. At least with the 'e' plug, it's now the correct reach. Good thing it wasn't a 'z' which would probably cause the piston to hit the plug.

The 'g' is a fine center electrode vs. the 's' which is 2.5mm. I don't know if having a larger center electrode would make much of a difference, but I'd theorize that it would be more prone to fouling plugs with the standard electrode instead of the fine electrode.

The one step hotter plug I really doubt would make much of a difference, but you really want to get the right parts in when you are having problems with a machine. Experiment when it's running right.

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Well, Smacaroni knows much more than I when it comes to the difference in spark plugs. Wow, that was great!! However, from my experience, the finer electrode fouls out before the large electrode. The finer electrode burns hotter however, the large surface area of the larger electrode will take more abuse. Therefore, harder to foul. Again, just from my experience's.

Again, agreed. When jetting you want to take out as many inconsistent variables as possible. (ie., fuel mix, plugs, clean air cleaners, temperatures, ect., ect.) I've personally never had a bike have or need a drastic change in jetting due to the spark plug. I have had them smooth out or give a slight increase of power to an existing jetting. But, the more consistent variables you can run the easier it is to run consists jetting. I would think that a stock plug or maybe one hotter would be more than fine.

To me, it sounds like your running lean. Try setting your main jet first, then your pilot jet, air jet and idle screw (mainly for idle only anyway), then finish with your needle jet. This should get you really close however, be prepared for some slight bleeding between these jet zones. Some fine tunning could be needed.

In a nut shell. Get the motor where it will clean out at high RPMs. Then get it to idle. Then fix the midrange. Fine tune from there. This is how we do it.

Hope that helps, bro!!

Edited by motodogg01

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thanks for all the help man, i appreciate it!

i just got a br9ev and a 200 main...and some new grips..lol,

im mixing some 32:1 right now, and i just put a 12 tooth turner sprocket on i got from motosport for 10 bucks, couldnt resist!

ill report back in a few

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they might have given me the wrong main jet.

put it in and it ran fine for a minute, rode it, sounded a little better,

so i put 32:1 in it and the new plug. started to run like crap,

then crappier, put the plug i had in it originally, still ran like crap.

its like the main jets not even there and wont go past half or so throttle, but when it is revving under half throttle its real smokey, hmmmmm....

maybe mechanical error?

ill give it a go and re try tomorrow.

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Is 40:1 what the manufacture states to run? If it is, then yes, you will have to re jet to run 32:1. If it just started smoking like that then its the 32:1 mix. Not a big deal if your re-jetting.

Go back to the stock jetting. Main, pilot, clip position. Everything. Then go back to my previous post and start there. Considering we can't verify if it's lean or rich over the Internet try going down (or up, which ever is needed) at the main jet first until the motor will run out. Then your pilot jet, air jet and idle screw (mainly for idle only anyway), then finish with your needle jet. This should get you really close however, be prepared for some slight bleeding between these jet zones. Some fine tunning could be needed.

If you can't get the jetting close enough to run out the motor reasonably smooth then you probably do have mechanical issues. It sounds like it would be more of a top-end issues at this point than a crank seal. When our 85's burn up a top-end they wont hold a jetting. No matter what I do or which way I jet it doesn't work.

Edited by motodogg01

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32:1 is what kawi says.

i ran 40:1 again and it still ran crappy.

so i went back to the shop,

turns out they gave me the wrong 200 main jet!

so they gave me a 190 jet made for my carb this time, and i bought a 25 pilot, but wrong pilot...👍

with the 190, its running SCARY fast! deffinately still lean. ill have to try a 195+.

right now im putting 32:1 back in.

Edited by dylans503

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32:1 is running awesome!

the 190 seems a tad lean still

probably gonna get a 198 mj and 28 pj monday

or should i go to a stock 200? i dont want to spend money and time switching out jets really (broke teen with no car)

pilot jet still seems rich.

Edited by dylans503

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i dont want to spend money and time switching out jets really (broke teen with no car)

Welcome to the "jetting boxing ring" I spoke about a few posts ago. Jetting is a lot of trial and error. Sound like you're starting to get a handle on it though!! That's cool!!

When jetting and you think you're close make small adjustments and only change one jet at a time. "Try" to keep the jetting zones separate. Therefore, go from the 190 to the 195 to a 198, ect., ect. Also, if you get it jetted perfect now (lets say temperatures around 60 degrees) you'll have to fine tune your jetting up or down as the degree changes up or down more than 20/25 degrees. FYI.

Remember, the main jet before jetting the pilot. Needle last.

I found this post below on another thread and thought of you. It's referring to a KX100 however, the part were it talks about reading the spark plug and running that test is what I thought might help you.

he had one till about 3 weeks ago. We just sold it.

If you're not a fast rider, but soon will be, I guarantee it, you won't have any interanl issues. Just remeber, very frequent trans oil changes. Also if you're not on the pipe alot and get your jetting dialed in, Be sure to run 32:1. It'll keep the bottom end well lubricated.

I can suggest jetting but only you will be able to tell. Get some NGK BR8es plugs, they're cheap and the bike runs great on them. Take the pilot down 1 size and the main down 2. Start with a new plug and run it for about 3-5 min from cruisingt around to some wide open, up throught he gears, run. Pull the plug, take a looksee. Should be a nice chocolate brown or even still black but not gas-soaked wet. If it's a light tan or white, Take the pilot back up one and run the same plug to see if it richens up. Same procedure. If it's good then part 2...

Install new plug, run around for a minute or 2 and get to a place where you can get to atleast 3rd gear wide open, 4th or 5th is better. (be careful).

Do a WOT run. As soon as you arer about to let off the gas, pull in clutch and immediately kill the bike and let it coast to a stop. Pull plug, should be tan to black. White = go up 2 on main, tan = 1 up, brown to dry black = good. Wet = down 1 on main. If you start to foul plugs, stay on the pipe more

Oh and be sure to check out the FAQ section at the top of this 2 stroke section. There's some good info there, especially the jetting.

Edited by motodogg01

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I would argue that you want to get the pilot straightened out first. It's hard to jet a bike on the main when it won't idle.

Plus, the KX60 has a main jet access hole that makes swapping mains fairly easy.

Otherwise, follow motodogg's advice.

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Yeah, it does make it difficult at times for sure.

I pushed the main jet first because the motor wouldn't clean out. That told me that there was possibly a bigger issue some where outside the pilot. In my experience's, fixing the problem with the motor cleaning out first usually address the pilot issue in the process. Remember, there are two issues. 1. The motor wont idle. 2. The motor wont clean out. Which is the bigger issue? I say, "The motor not cleaning out".

If the motor wont idle because it's lean or rich at the main then "fixing" the idle by richening or leaning pilot would only be a temporary fix. The motor still wont clean out. It's still rich or lean at the main. Right?%@*

In my experience, addressing the main first and getting the motor to clean out then addressing the idle (pilot, air-screw, idle screw), then the midrange (needle jet) is a easier attach in this scenario.

However, there are several ways to skin a cat and I'm no true" professional" by any means. I'm really no more than a "shade tree" mechanic that's been working on these two-strokes for about thirty-years, or so. Currently, we have a few boys racing in the 85cc class so jetting is a regular issue (in-doors/out-doors/summer/winter) That's why I love this website so much. I learn something new everyday.

With that being said, and from my experience's, this is the may I would attach this situation and why.

I hope that helps, boys!!

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so i took back the 190 main and got a 200.

and i got 27.5 pilot.

i may have to put the 13 tooth back on cause this thing gets up!!!

the idle is still hanging though, should i go back to the 30 pilot?

or am i still to rich?

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