First 2-stroke bike

[Xtremesports445]

Well, i think i've found the bike for me. It's a 2002 kx 125(w/a racing clutch and procircuit exhaust). I have some questions about it, since it will be my first 2-stroke bike. I rode the bike around a little just on some asphalt, and i was wondering how easily it should pop a wheelie. Should i be able to just give it gas and the front end pops up? Also, this is a big step up for me going up from a ttr125 to this. I was wondering what things i need to be careful about until i get used to the power. I did already ride a little bit, and that thing was fast! :yikes: A welcome change from the ttr. One more thing, what premix ratio of gas to oil should i use? I think he was using 24:1, but i've heard up to 40:1 is fine too.
thanks for the answers. anything else i should know is welcome

 

[KX02]

I used to have a 2002 KX125, very reliable bike. You have to be fairly aggressive to wheelie 125's, you'll get to that later. I would run it between 40:1 and 32:1 and use a good synthetic oil. Enjoy the bike!

 

[Stryke]

DEFINATLY 40:1 the manual recommends 32:1 ive talked to many pro riders and they all say 40:1 is better, some guys even use nearly 50:1 However 40:1 is very safe and probly best route. 24:1 is to low and the motor will run like crap with 24:1. Keep adding 40:1 and it will soo flush out the oil and be 40:1 completely. :cool:

Opti 2 high performance oil with a combination of 91 octane runs just beautiful in the kx125 at 40:1.

 

[ellandoh]

DEFINATLY 40:1 the manual recommends 32:1 ive talked to many pro riders and they all say 40:1 is better, some guys even use nearly 50:1 However 40:1 is very safe and probly best route. 24:1 is to low and the motor will run like crap with 24:1. Keep adding 40:1 and it will soo flush out the oil and be 40:1 completely. :cool:

Opti 2 high performance oil with a combination of 91 octane runs just beautiful in the kx125 at 40:1.

which pros have you talked to and can i get some autographs??

32;1 is best for a 125 especially if youre riding like a pro , and said pro is mixing his own fuel

 

[Stryke]

^^^Have some respect, and yes btw i have talked to many pro class riders with 125s they all run 40:1. BTW its pretty simple to walk over at the pits and ask, "what type of oil gas mixture do u use in your 125?" THEY WILL TELL YOU. Thats how i found out what to use b/c when i used 32:1 in my 125 it was spitting way to much smoke and i was fouling plugs, more that when using 40:1.

 

[ellandoh]

now i believe you even less, name some names, or maybe an event , something. tell us the mechanics behind your theory on the 40;1 deal . temps altitudes conditions terrain etc.

if i could find a pro that still rides a 125 the way it was designed to be ridden, i would lay a bet he'd be more likely to use 20;1 than 40;1

 

[FruDaddy]

I rode the bike around a little just on some asphalt, and i was wondering how easily it should pop a wheelie....I was wondering what things i need to be careful about until i get used to the power.

First thing to be careful about is trying to do wheelies. 32:1 - 40:1 is OK, i think that for petroleum based oils you should shoot for 32 while synthetics perform better at 40. Personally, I run Motul 800 at 40:1 in both KX65's and a KX250. You will have to jet the carb accordingly once you decide, unless you decide to stick with the previous owners oil and ratio. I think that 24:1 wuld be too much oil for the combustion process, and 50:1 would burn parts way too fast.

 

[Stryke]

now i believe you even less, name some names, or maybe an event , something. tell us the mechanics behind your theory on the 40;1 deal . temps altitudes conditions terrain etc.

if i could find a pro that still rides a 125 the way it was designed to be ridden, i would lay a bet he'd be more likely to use 20;1 than 40;1

I never got any names, just walking downj the pits and chatting with a few ppl is enough to gain sum tips. Is it that hardx to believe? Your a joke im betting u think a pro is only AMA Ricky Charmicheal skill and you can never meet anyone. However if u have gone to any local motocross race your gonna find "pro" riders who do know the best oil to gas mixture. Being a pro doesnt mean your rish famous and rare to find. Im willing to bet that out of the 1000s of motocross races every day in the us there is atleast 5-10 good enought riders that can easily call themselves pros and or B+ riders. BTW your pretty narrow minded, and why dont you just stop mouthing me off already, b/c finding someone who is pro, intermediate etc.

 

[ellandoh]

you obviously have no knowledge of your own on the subject, and if you decide to believe anything you hear you shouldnt be passing off your pro secrets as gospel. i have a feeling the pro riders your talking about put what their dads buy them.

do a search on this board, youll find pros, youll even find their spark plug chops with fuel mixtures, youll find that a pro can jet their bike to run on most any mixture he wants and none of them can find a reason to go higher than 32;1 for the added protection as well as other factors, give advise when youre reasonably sure you have some GOOD to contribute. or go hang in the general discussion section

 

[FruDaddy]

you obviously have no knowledge of your own on the subject, and if you decide to believe anything you hear you shouldnt be passing off your pro secrets as gospel. i have a feeling the pro riders your talking about put what their dads buy them.

do a search on this board, youll find pros, youll even find their spark plug chops with fuel mixtures, youll find that a pro can jet their bike to run on most any mixture he wants and none of them can find a reason to go higher than 32;1 for the added protection as well as other factors, give advise when youre reasonably sure you have some GOOD to contribute. or go hang in the general discussion section

ellendoh, usually I have no reason to dispute your posts, but it seems that you are being unnecessarily argumentative, while Stryke may have recieved all of his knowledge by speaking with nameless local pros, you are not even disputing his statements. His info is gained in the same manner as 90% of this board, by asking someone that seems to know more. And your statements just back his up, "youll find that a pro can jet their bike to run on most any mixture he wants ". Aren't you just saying, pick one and jet accordingly.

 

[ellandoh]

Aren't you just saying, pick one and jet accordingly.

125's appreciate the oil to be 32 ;1 or richer when ridden properly

i take it you read post #3 , and believe it :whoa:

 

[Stryke]

I look at it this way, 32:1 u will be spitting out 10x more smoke. Your engine is not gaining any benifit over using 40:1, your wasting your money on oil, and more oil and less gas can only mean less power. Think about how the motor works if u had less oil in the gas it would run faster. I ride with one of my friends as well, his bike runs 32:1 b/c he only does what the manual says. We ride together all the time and my top end has lasted over a year longer than his. We both ride the same. Secondly 40:1 will not wreck your motor, in fact 40:1 may even be to much depending on what oil you use. I can see if u use some cheapo no name oil its gonna be hard on the motor but 40:1 with high performance oil is probly safer than some 32:1 other brand.

If the oil itself recommends u to use it at 40:1 use it at 40:1 and if it recommends it at 32:1 use it at that.

 

[Xtremesports445]

Yeah, i made a mistake, i don't think he was actually using 24:1, it's just what i thought he said because he was kind of hard to understand. he said he used 12 ounces and 4 gallons, and i did the math it came out to be about 1:42.6

 

[FruDaddy]

i take it you read post #3 , and believe it :whoa:

Yes, I did read #3 and hove no reason to doubt the he has spoken to one or more local A riders (in my area they get paid to win) and listened to what they had to say.
When choosing an oil ratio, I believe your best bet would be to buy a bottle, put away the owners manual (they all seem to say 32), and look at the back of the bottle. The oil manufacturer wants your bike to both perform and last while using their product so that you will continue to buy the same stuff, and they know what works with their products.
As a general rule of thumb, petroleums seem to like more oil (32:1) and synthetics require less oil to do the job (40:1), but even that's not an absolute.

 

[ellandoh]

go get yourself some amsoil saber and run your bike at 100;1 like they recommend on their bottle. youll save alot of money then :nod: being an A rider doesnt guarantee you can put air in your tires

to the original poster if you are going to ride a 125 and are not yet pushing the bike hard 40:1 is good for you but when and if you start riding it with confidence and pushing the bike or plan on riding the bike in sandy conditions you'll be doing yourself a favor by going with 32:1. either way if your bike smokes or bogs or has any other issues you can put a band aid on it like the others in this thread by playing with the oil ratio or you can learn for your self to do it right , very quickly and easily below.


Spanky's jetting guide:

A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. If you have never jetted your bike correctly, you will almost certainly gain some performance at some point in the bike's powerband. A cleanly jetted pilot circuit can be the difference between having to clutch the bike out of a turn or not. The needle can make all the difference in the world for the power of the machine in most situations, as it controls the throttle range that most riders spend most of their time using. A correctly sized main jet could mean the difference between being able to rev out high enough to not have to shift one more time at the end of the straight, or the power falling flat on top and requiring you to make that extra shift.
Are you fouling plugs? Many people will tell you all sorts of band-aid fixes, from running less oil, to running a hotter plug. Both are incorrect fixes for plug fouling. It's all in the jetting.
The only way to know what jetting changes you will need is by trial-and-error. No one can give you jetting specs, because every bike is different, every rider has a different style, and jetting is totally weather dependent. Unless the person telling you what jets to use is riding an identical bike, on the exact same track, at the same time, his recommendations are meaningless.
Jetting is fairly simple, and is a useful skill to learn if you ride a two-stroke and want it to perform at it's best.
It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving.
Before you start to rejet your bike, you need a clean air filter, a fresh plug (actually you need several plugs to do plug-chop tests for the main jet), and fresh fuel. One important detail: Make sure the engine is in good mechanical condition. If your engine has a worn top-end, fix it first. Trying to jet a worn out engine is a waste of time. The same goes for reeds that don't seal properly, and a silencer that needs re-packing. Worn reeds will mimic rich jetting, and worn rings will mimic lean jetting.
Before you start the jet testing, install a fresh plug. Set the float level to the proper specs, an incorrect float height will affect your jetting all across the throttle range.
Warm the bike completely, and shut it off.
As already stated, start with the pilot circuit. Turn the airscrew all the way in, then turn it out 1.5 turns to start. Start the engine, and turn the idle screw in until you get a slightly fast idle, or hold the throttle just barely cracked, to keep the engine idleing. Turn the airscrew slowly in, and then out, until you find the point where the idle is fastest. Stop there. Do not open the screw any farther, or your throttle response will be flat and mushy, and the bike may even bog. This is only the starting point, we will still have to tune the airscrew for the best response.
Now is the time to determine if you have the correct pilot installed in your carb. The airscrew position determines this for you, making it very simple. If your airscrew is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet.
Once you have determined (and installed it if it's necessary to change it) the correct pilot jet size, and tuned the airscrew for the fastest idle, it's time to tune the airscrew for the best throttle response. Again, make sure the bike is at full operating temperature. Set the idle back down (the bike should still idle, despite what you read in the Moto Tabloids), and ride the bike, using closed-to-1/4 throttle transitions. Turn the airscrew slightly in either direction until you find the point that gives you the best response when cracking the throttle open. Most bikes are sensitive to changes as small as 1/8 of a turn.
The airscrew is not a set-it-and-leave-it adjustment. You have to constantly re-adjust the airscrew to compensate for changing outdoor temps and humidity. An airscrew setting that is perfect in the cool morning air will likely be too rich in the heat of the mid-day.
Now, it's time to work on the needle. Mark the throttle grip at 1/4 and 3/4 openings. Ride the bike between these two marks. If the bike bogs for a second before responding to throttle, lower the clip (raising the needle) a notch at a time until the engine picks up smoothly. If the bike sputters or sounds rough when giving it throttle, raise the clip (lowering the needle) until it runs cleanly. There isn't really any way to test the needle other than by feel, but it's usually quite obvious when it's right or wrong.
Last is the main jet. The main jet affects from 1/2 to full throttle. The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan.
Once you have a little bit of experience with jetting changes, and you start to learn the difference in feel between "rich" and "lean", you'll begin to learn, just from the sound of the exhaust and the feel of the power, not only if the bike is running rich or lean, but even which one of the carb circuits is the culprit.
The slide is also a tuning variable for jetting, but slides are very expensive, and few bikes need different slides, so we won't go into that here.
Keep in mind, even though this article is intended primarily for two-strokes, four-strokes also need proper jetting to perform right, although they are not quite as fussy as their oil-burning cousins. The only real difference in the two is with the pilot circuit. Two-strokes have an air screw that you screw in to make the jetting richer, and screw out to make the jetting leaner. Four-strokes, on the other hand, have a fuel adjustment screw that you screw in to make the jetting leaner, and out to make it richer.

 

[robwbright]

Unless I'm mistaken . . .

32:1 = a bit less wear on the piston, ring, cylinder than 40:1 - all other things being equal.

I suspect that pro riders probably have the time and money to rebuild their motors more often than the normal person and that they do rebuild them more often.

I doubt there is really that much difference in wear between 32:1 and 40:1, but I plan on staying with 32:1 for increased lubrication. Plus, it's easier to measure 4 oz per gallon as opposed to 3.2 oz per gallon. ;)

And no, I don't have excessive smoke.

 

[FruDaddy]

being an A rider doesnt guarantee you can put air in your tires

Funny, I almost added that I wouldn't ask RC or Stewart for an opinion about lubrication.
Oh, but I do love seeing Spanky's guide com out of hiding. :cool: Who is Spanky anyway?

 

[ellandoh]

spanky , is a mysterious legend , i hear even the great one knows not where to find him!


by great one, i'm speaking of a Mr. Chuck Norris :)


i found that on motocross.com, have no idea who Spanky is, but he deserves credit for such an easy to understand write up. i have since modified the technique a little for what works best for me but it is a great starting point.

 

[highmileage]

^^^Have some respect, and yes btw i have talked to many pro class riders with 125s they all run 40:1. BTW its pretty simple to walk over at the pits and ask, "what type of oil gas mixture do u use in your 125?" THEY WILL TELL YOU. Thats how i found out what to use b/c when i used 32:1 in my 125 it was spitting way to much smoke and i was fouling plugs, more that when using 40:1.

1) This is the first clue of you not knowing anything about 2 strokes and fuel ratios. If you were properly jetted for 32:1 there is no problem to begin with. Going to a richer fuel mixture (40:1 from 32:1) is not going to solve wet spark plugs and smoking issues (rich conditions) by adding a richer fuel mixture...unless it is jetted properly for that richer fuel mixture...

2) Smoking can be as much a function of the oil used/oil type as some smoke more and burn dirtier than others. Some oils burn cleaner, have less spooge, and are less predisposed to separating than others....this is not particularly a ratio issue solely.

3) All mix ratios (20:1 to 100:1), IF NOT JETTED PROPERLY, will run like crap and can be harmful to your nice engine...50, 65, 85, 100, 125, 250, 300, or 500cc....no matter. Clean jetting can be had at 20:1 or 100:1 with the right oil, right gas, and right jets.

4) The easiest way to jet a 2 stroke cleanly is to decide on a fuel/oil ratio (keep it consistent both the gas, the ratio, and the oil) and then dial it in for elevation, temperature, humidity, and for barometric pressure...Keep good notes in a jetting notebook on air screw, pilot, needle, clip position, and main along with ambient climate conditions...period.

5) Jetting is an active tuning and maintanence act...not a "set it and forget it" type of thing. You can have the most wicked motor ever built, but jetted improperly it isn't worth its value in scrap metal.

 

[DirtDawger]

I agree with highmilage. Pick a qaulity oil and jet your bike accordingly. In my years of mixing fuel I prefere to run 42 to 1 Yamalube. All my bikes have run this mix from the ole ladys KX 100 to all my various 250's. I use this combination because it burns relativley clean with minimun power valve gumming.

Since 2 stroke oil is not as combustible as gasoline adding more oil is in effect leaning the bike. Less oil is a richer mixture. Thats why you can't jet a bike on one mixture then start fooling around with different oils and different ratios and expect to get objective results.

 

[Miek]

I never got any names, just walking downj the pits and chatting with a few ppl is enough to gain sum tips. Is it that hardx to believe? Your a joke im betting u think a pro is only AMA Ricky Charmicheal skill and you can never meet anyone. However if u have gone to any local motocross race your gonna find "pro" riders who do know the best oil to gas mixture. Being a pro doesnt mean your rish famous and rare to find. Im willing to bet that out of the 1000s of motocross races every day in the us there is atleast 5-10 good enought riders that can easily call themselves pros and or B+ riders. BTW your pretty narrow minded, and why dont you just stop mouthing me off already, b/c finding someone who is pro, intermediate etc.

How to properly jet the 2002
I have an 03 KX125 and am going to go a step leaner than Team Green reccomend but I run 50:1
Here's the gospel according to Kawasaki's Team Green 40:1 go to teamgreennews.ca and check out the tech section this is likely for Cali but hey its a good start even for Fredericton New Brunswick. As far as asking the Pros just head on down to the nationals and ask any Pro (at least in Canada) Cooke, JRS, Klatt are all pro level Canadian Riders that can and have competed against American's If you haven't heard of them yet, just open up RacerX or wait it wont be long

 

[Skinnghi]

My Hondas got a 380 jet, needles on the second setting, and I run 40:1. Perfect for me, all I did was move my needle and lean it up a bit.

 

[2 strokes for life]

I some times use 100:1. No smoke from my raer end. Like a 4 stroke but better power.

 

[2 strokes for life]

I mostly use 50:1.