Understanding Carb Jets and Needles - Jetting 101 - Dirt Bike
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- Опубліковано 11 вер 2024
- This video gives some of the basics you need to know about jets and needles in your dirt bike carb. We talk about how they effects your performance. This is intended as an introduction into the topic.
Epic video! Jetting can be so confusing especially if you're new to bikes. Thank you again, today I've learned so much!
After 30 + years of riding and being around riders, jetting is the most universally misunderstood skill-sets of riding, regardless of the style or discipline of riding. The way to understanding is to understand the basic function of the carburetor and the systems that makeup the carburetor. This video is a great basic understand "101" period of instruction to get you there. There is much more to lean and discover but this is a great place to start and a great video none the less.
Great job..!
(There is much more to "lean" and discover) Learn and discover...... I think you mean. A Freudian slip. Nothing like the smell of two stroke in the morning. I hope I don't come across as a bit rich (can't help myself now)...... 30+ years here also, opps, closer to 40+ now. But yep "101' basics here, agreed.
I appreciate the clips of riding throughout for those of us with short attention spans! Really tho this is some good insight. I've been searching for info on jetting in layman's terms for my trip to Colorado. I ride now between 1000-1500 feet in illinois so there will be a big elevation difference. I've watched your video of how to change the main jet and needle and it seems very simple.
Yeah, make sure to lean that carb out along the lines of the specs for your carb and you'll do fine. If you don't adjust the carb before riding at the much higher altitudes here in the Rockies, your bike will be choking (literally) on the fuel and will run very "boggy".
Oldie but a goodie, and still quite applicable! Thanks!
Thanks for making a really clear statement on how to setup and run a MX 2T. I only wish I had seen this last year, since then i have destroyed 2 2T engines by running the wrong mixture I made the mistake of only changing the Oil to Petrol ratio and not understanding the need to consider the amount of air flowing through the Carb.
Your videos should be a fundemental part of 2T ownership! Please continue making quality videos
+Dirt Bike Channel Thanks for taking the time to do these videos. These jetting vids have been supper helpful
Bravo Company! So cool to see them in random places and communities. Right on my man!
Thanks for the info! I've worked on classic car carbs before, but have not done any bikes, and I'm now diving into that world. It is the same, but also different(huh?). This is a great explanatory vid!
That was hands down the best video ive seen on this subject yet!!! thanks again!!
Thanks man! Dude this finally makes sense now. I can finally set mine up properly.
this video solves all my problems. Finally understand jetting for my 2stroker.God bless you!
Glad to help Ivan! That is a nice looking bike you've got there. I love the orange frame!
One more question.. How do you know which needle is richer and which one is leaner??
Ivan Mihaljevic
The only way I know of is by looking in your user manual.
great video.u have alot of tips and tricks that really can help. one thing i dont thing u mention in this video though. that each komponent in the carb jets,needle, pilot air screw, Each affect different areas of the throttle. thats something u got to know when jetting and dont have a chart or a stock bike. and a tip for those who dont understand just jet the typical behavior of the different jets and stuff, The sparkplugg says ALOT about how your bike is running either lean or rich. :)
Can you find me a table like that for my yz250 in a link or somewhere to buy or download it?
I ordered a yz250X and will be back to a carb again. what are some characteristics of a lean running bike and of a rich running bike so I can be aware of this. Great video series.... Keep em coming!
Andrew Puetz This is a good video on this from a man who knows what he's talking about. ua-cam.com/video/zVzqqpgviyI/v-deo.html
absolutely fantastic video. I've watched a few videos but yours really helped me make sense of it all. Keep up the good work!
love your videos. great help. Very professional.
Thanks for noticing.
I really like your videos. Well done! We ride the same bike. I love it! I was on a 380 two stroke and was worried getting the new 300 would be a disappointment. Instead it has been better than expected, and just as snappy, if not more so. I ride in the woods of Oregon at about 1500-2000 feet. This video was helpful for when I plan a riding trip to Utah. My brothers and I like to get out that way every few years. Maybe see you out there sometime. Haha. Happy riding.
I'd love to ride Oregon some day. Isn't the 300 just amazing in so many ways?
It is incredible! So is riding in the Great Northwest. Come out this way and I'll show you around. Bring your bike and your recommend. Haha.
Jayson Rowley Which recommend would that be?
Temple?
Jayson Rowley
I figured that's what you were referring to :) It's always in my wallet, so it shouldn't be too much trouble to bring it... Us "temple going" brothers have to stick together, right?
I understand all about jetting now thanks very much.
I'm 9yrs late here but this info is golden
Thanks for the video! Im picking up a '15 250xc sometime this week and jetting has been a thing on my mind so this really helped
New bike this week??!! I'm jealous of you! Glad to have helped a bit.
It probably won't be ridden much until march :( its -5 right now in ohio haha
*****
Gives you plenty of time to get it ready!
Thank you, thank you. Exactly what I was looking for.
from Australia nice video mate really really helpful and full of details
+Abrahim Yehia Greetings from the north!
You to brother if i get stuck on jetting or other issues will let you know. Thanks once again buddy ☺
Thanks for the video. You did a good job of explaining that table (I too own a ktm 300 xcw) and the dynamics.
+Barry Spindler You are welcome.
My 380 Mxc is the most difficult ever to jet ,I'm in upstate Ny at sea level. I'm going to buy a 40 Pwk As and see if it responds better all around rite out of the box with the bigger carb. Nice Channel and Videos!
Thanks for the video, it explains jetting perfectly.
One suggestion is to perhaps not have background videos in the background when you are explaining things as it distracts your attention. Just some constructive criticism.
Can't please everyone :)
shabsZA NO I LOVE THAT! IF HE DIDNT DO THAT I WOULD'VE SKIPPED THE VIDEO BECAUSE I HAVE A SHORT ATTENTION SPAN SO SHUT THE FUCK UP
PlayrSlayerz rofl, careful not to loose attention whilst you changing gear - mase doos
shabsZA English, please
PlayrSlayerz Let's keep this family friendly folks :)_
Do you judge that the bike is too rich based on feel or the spark plug? I'm not sure how you're doing it in 5 minutes or less.
I love your videos man your extremely helpful and your such a good rider thank you so much for the videos they help a lot
Thanks man, glad you are getting something out of them.
Man...awesome video. I actually understand now. Although, numbering and such is different with my RM but the point is received well!
wow, very good information
I recognize allot of the clips in this video. They're some some of my favorite places to ride.
Alex Dorsey Where do you think they are?
I could swear the first few were by eagle mountain city center. I've seen you up there before.
Alex Dorsey
Nicely done Alex. Yeah a few of those clips were shot out there on Valentines Day 2015. Just a quick ride to get out of the house, you know.
That was sooo helpful thank you so much:)
Will this chart work for a 4stroke? I'm in kamas Utah elevation is 6000 through 7500 feet. ❤ your video. I've learned a lot from you
How does air flow into the bike affect how you choose your jetting, needle, etc. I made a few mods to my ttr-230 recently that allow for more air flow and open up the stock exhaust. Should I still go by stock recommendations by yamaha?
Should I still follow this chart if I have FMF pipe and silencer?
I have a 2013 Ktm 250xcw-w
I ride sea level to 5,500 feet typically. What jet size would be best for my carburetor on my yz250x?
What handguards are you using in this video? Would you still recommend them? Using them on the next 300xc you have?
Thanks!
Jim
I just put a 292cc Big Bore on my YZ. I will have to go leaner on the jetting to get the best performance with more cylinder area. Right?Thanks for this information about jetting.
Utah!!????!!! no way!! Now these videos are even more amazing to me cause its more relevant to me :)
x_LiZe_x Born and Bred in Utah.
Sweetness :) Same here. Just recently got into dirt bikes and your channel really helps clarify things out
+Dirt Bike Channel I feel like you can always identify a fellow Utahn haha I definitely had my suspicions when I first started watching your channel
Great video, everything was easy to follow. But I have a question...My bike (2002 cr125) runs good when you get on it, but loads up the plug when idling or when not riding it real hard. Does that mean I would need to run a leaner pilot jet?
where can i get that technical data sheet for my bike (1998 yz250)
Ok, so lets say your bike is running good across the board except when you just crack the throttle a hair and it bogs for just a second before it takes off. What would cause that and how do I fix it?
i would say you'r running rich and when you'r trying to put much gases, your throttle don't breath enough air to burn everything, so he is bukking of over-fuel ? but i'm no expert here
Where can I download this graph for my ktm 150
love your videos man
+Phuck Liberals Thanks brother.
just picked my new 16 300xc and am learning the carb.I ride in the pacific NW anywhere from 500 ft to 5000 ft mostly in the summer temps between 50and 80 degrees.I"m mixing my ratio 50:1.I"m almost done with my first tank and I'm sure I'm running rich as I'm getiing spooge from the exhaust.I"m running factory needle and main jet settings.Question is, if I wanted to lean just a little bit to minimize the spooge but not too much to increase chance of blowing motor,Where should I start first?raising needle clip first or changing main jet or a combo of the two?Thanks! Great channel btw.Your new vid on the 300xc was the reason I picked one up.Absolutley love it so far.Coming off a 14 350 EXC
+tombba I'd start with leaning out the needle position one or two positions. Sometimes you will get "spooge" simply because you are riding slow (like when breaking in the motor for a tank or two). Most of the time though, it's an indication that your fuel mixture is too rich. It's not a bad thing to run a bit rich for a tank or two in the beginning though. I'm really glad that you are enjoying the amazing machine you just bought.
good advice.I tend to lug coming off a 4s.I understand the needle pos. controls 1/4 to3/4 throttle pos.should be the first place to start I assume.so I"ll raise it to 3rd pos. from 4th pos. and see how she does.thanks
What's a good needle for a 210 jet? Thanks for the videos!
Where can i get a copy of the tech sheet you are using? Very informative video too...Thanks
+Andrew Wilson Which tech sheet? I am just using the manual. You can download a free copy of KTMs website.
+Dirt Bike Channel Cheers mate! Found it.
Now this is a good video with information!! Starting to understand a bit more about jetting.
How do you have that chart for your carburator? I cant find anywhere for my Keihin PWKS 38. Can you please help with that?!!
Thank you.
Nice video, thanks!
Treta video. I recently changed my exhaust system. The bike was running fine before. But now, with the new exhaust, is bogging at low rpm. I'm thinking about setting my jetting to help getting more fuel in. How can I accomplish that? Different needle? Of same needle in different position? Do you have any suggestion?
Ricardo Garcia Do you have an owners manual? Many times they will give a jetting table for various altitudes. That is usually a good starting point.
+Ricardo Garcia i know it a long time ago :P but that issue u had point toward that your idlejet is to smal. put in one that probably 2 sizes bigger and it will probably be fine. u kind of have to try and see wich jet is best.
I have a KTM 200 EXC, which I'm getting road approved. The seller gave me an original 7kW pipe, which is of course restricted. My question is, can I just leave the jets and needles as they are currently set (for the unrestricted pipe), or do I need to change them? If I need to change them, where can I find exactly which ones to use? Thanks!
You will probably need to reject it, you can try to look up online or in the manual to find what the original jetting was at and set it accordingly
*rejet
This made things so much more clearer! Thanks I just have one quick question, the bigger the jet (for example 185) is more rich than a 180 right? I have a 04 yz250f with a 185 main and a 48 pilot. The stock is a 180 main and a 42 pilot. Would this new jetting (not the stock one) be more rich or lean?
+MrChaosflying Bigger numbers let more fuel through them. That means richer.
So, did the bike come with all the needles and jets, or was that a separate purchase?
+rc pilot They some with some stuff, but you generally need to make a separate purchase to have all the things you need for your elevation.
+Dirt Bike Channel where did you get them at?
+rc pilot Rocky Mountain ATV/MC
+Dirt Bike Channel ok, thanks
Could you do a video, of how to remove the KTM 300 carb and how to make the changes to it as you describe in this video.
Waleed Najm We have a video showing how to jet the carb. There is no need to remove it.
Where's did u get that paper chart?
Where can I find this sheet?
Hey quick question i too live in northern utah so i want to know how to run my jets and needle at higher elevation i have a 2002 yz250 with a PWK38S Kehin carberator just wondering where i could find a chart like this for my bike i looked all through my manual and could not find one. Thanks for all the help, and you have an awesome channel lots of good information.
Hi Logan. I also have a PWK38S Kehin carberator on my bike (GasGas 2013 EC300 Racing), and cant find a chart for it..... Did you find one since? Hope you can help with that...
Have you tried the NECJ suzuki needle in your KTM? I liked it a lot and I use it year-round and just change clips. I ride in Cedar City and St. George (Hurricane, Washington, etc).
modestmoose83 I haven't tried that needle.
Good Video! But I have a question...I'm riding from 250 to 700m, so i'm gonna use the chart for 300 to 700m (i think that 50m are not problem), but in my area the temps are changing non-stop...they are from -15 to 40C (from 5 to 104F)....my question is can i stuck with the settings for -6 to 5C for the winter mounths and 25 to 36C for the summer time? Is it going to be a problem?
just test it ;)
you dont gonna get max power but if the bike runs good you dont have to change it everytime unless you are racing and need every hp ^^
Thanks for the answear!
where do you get those sheets
Does going higher on the needle make it more lean or rich?
Raising the needle clip position makes it leaner for 1/4 to 3/4 throttle position basically. Easy option is to buy a lectron carb.
Malky 52 you can buy me one if you’d like 😂
Cool video. what I'd like to know is when do you adjust needle clip position and how does it effect to bike.
+MK116Alex That will lean or enrichen the fuel air mixture. We talk about this in the video (if my memory serves correct).
+Dirt Bike Channel sorry about that. perhaps I was daydreaming a bit. :-) So if I need to make it a bit more rich due to local temp change should I go up one more notch and see how that works before actually changing any jets? I also noticed that since it's cooler now that the bike tends to surge at idle.
I KNEW HE WAS FROM UTAH. He just looks like a Utah guy lol. How he highlighted the carb settings for St. George and The rockies haha
Thanks for the great content. I just bought a 2017 250 XCW. I am used to idiot proof EFI on the 4 strokes so no experience with carburetors. I found the manual page with carb settings that you showed on the video. My question is whether I should always follow all 5 settings in each box or if you can "mix" with different jets, needles without harming the engine? Apology if this is obvious to others but I am new to non-EFI. Thanks.
You can mix and match for sure. The manual is also very rich in all the settings. Feel free to go leaner than they show there. I ALWAYS have to go leaner than the jetting chart in the manual to get them to run correctly.
PLEASE do not just "jet" your carb for the fun of it... You only need to "jet" your bike when you:1. Change altitude (500 ft or more) for long rides. 2. Modify your engine and exhaust system...
..... Since you stated you have no experience with carburetors do your self a favor and leave it alone!!!!.or become friends with your mechanic and forget about your money!!!
If you start fouling spark plugs find some one that can read your plug to tell you if you are using too much oil or the main jet is too big. (there is a BIG difference) If you can't find someone that know how to do this,,, try a new, GOOD, 2 stroke mechanic..some one that has experience in building 2 stroke racing engines that last,, they should be able to "read a spark plug"!
When installing a new pipe does it require a different jetting spec or is that not always the case.
Also, where did you buy you're needles and jets from been looking for a good set.
Typically speaking, if your bike is jetted properly, you won't need to change the jetting after installing a pipe.
Thanks for the Tip. Great video shows me more in depth about jetting.
Dave roger I just order the specific jets and needles that I want from Rocky Mountain ATV/MC. They should have each individual one you need and their shipping is really fast. I use my manual to figure out which ones I want based on the altitude and temperature around where I'll be riding. Don't buy the JD Jetting Kits. They are a rip off and you don't get much at all.
Thanks, just ordered mine not to long ago.
Does any of this apply to 4-srokes?
Sorry, im new to carbs
Yes, all of it applies to 4 strokes too. Same principles apply, I just love talking about 2 strokes all the time.
+Dirt Bike Channel Hi, do you know where I could print up the jetting page you are referring to in this video? it would be very useful to have. Thanks !! and great job on your vids, there spot on and very informative !!
KTM manuals have them in the back of the manual. You can download them from their site.
Cool, thanks for the reply !! Right after I left the comment I thought to myself that its probably in the manual...just asked cause I plan to get a newer 250 xc soon.
Subbed to your channel !! it's a good one !! do you happen to have a vid showing all the upgrades you did to your 250 xc ?
what would you get a 01 cr250 or 2016 yz250?
I'm assuming your asking him but, if I were you I would get the new yz 250 because you don't know what your getting with the Honda. If you have the knowledge to fix 2 stroke bikes then go for the Honda because it will probably be cheaper.
+Evan Radke I'm actually going to buy the new yz250x thank you for the reply though the reason for my decision is that the Honda is hard to find parts for since they are no longer being made by Honda .... I like buying new dirtbikes anyways because I know how I service my bike
How's that "new" YZ workin' out for ya?
So jetting has nothing to do with the type of riding you’re doing?
snapascrew unless your racing mx you should lean it out for more power where your pinned all the time , if your just casual riding for fun etc id jet according to your situation and preserving your life’s bike
I thought the fuel mixture screw did all this for you???
Hey Kyle, currently working on understanding jetting for my new 300. I'm about to head to Moab next weekend and was wondering if you had any recommendations on jetting. My chart also is totally different than yours for the 2016 300xc even though we seem to have the same model carburetor. Any ideas? Jeff Slavens recommended a 155 MJ for Moab, which is completely off the charts in my manual. Makes everything pretty confusing. Check the chart for my 2016. Page 125. Help is appreciated as always. Thanks for being awesome and answering my questions!! www.ktm.com/globalassets/product-manuals-pim-data/dok_bike_bed_16_3213330_en_om__sen__aepi__v1.pdf
+Chadillaac Email my at kyle@dirtbikechannel.com. I may have some suggestions for you.
+Dirt Bike Channel could you help me i have a snowmobile engine i am trying to jet. if you don't want to help i totally understand because its a totally different thing. my engine is running to rich. like what it does is start up and run for about 10 seconds then shuts off. i tried a higher ratio and that didn't work. Like gas comes right out of the exhaust. im just lost please help thanks.
I live at sea level can you help
What state do you live in? the area you're riding is calling my name!!! look AWESOME
99 Percent of the stuff on this channel is in Utah.
my 125 doesn't sound right. when its in high revs the engine sounds like it s gonna break. Think it's the carb?
i also had a ride of my friends bike. also a 125. it had twice as much power as my bike and sounded good.
Add some oil to that gas! lol
If you like your engine in the RUNNING condition = DO NOT attempt to "jet" you engine.. unless you KNOW how to read a spark plug correctly.. by this I mean, YOU can tell if the timing is off a lot, you can tell how your oil mixture is (too lean or too rich) or the jets are too small or too large... if you can't tell that your oil mixture is correct - PLEASE do not attempt to "jet" your engine..unless you like your mechanic and not your money...
If you are going riding in high altitudes and are going to ride in an area that is over 500 ft lower than your current altitude you must get the carb jetted richer!
Rule of thumb: 500 ft. altitude drop means lowering the needle one clip position(raising the needle)
over 500 ft. and every 1000 ft. drop in altitude is ONE FULL main jet size larger(along with the jet needle clip position)..usually after two clip positions lower you are at full rich with the needle and main jet changes will work.
What do you not understand?.. the entire concept of jetting?... Please explain what you do not understand...
BEWARE.. there are TOO MANY backyard "mechanics" that may have rebuilt their two stroke dirt bike, it runs and now they are an expert... they like to post video's on you tube to make you think they know what they are doing and most important to them - getting likes and comments from people who know even less than them! I laugh at some of these kids that do this very thing... it's funny,,
I will be glad to help you anyway I can..
There are some video's on you tube that are done by people that are true mechanics.. and they are good, knowledgeable, and smart mechanics... (most really great tuners just keep their knowledge to themselves!!)
Mechanic - someone that still changes tires..
Tuner - someone that works on race bikes..and lets the owners change tires..(I NEVER changed tires or fixed flats!)
I used to build two stroke racing engines that I guaranteed to last one race when I do a complete motor and I break it in. I still do a little port work..getting too old to do much anymore..
If your "mechanic" does not know how to read a spark plug to tell whether or not your oil mixture is rich or lean?.. find one that does... and there IS a way to read the oil mixture on a two-cycle spark plug!!
Anonymous Name hey I bought a brand new yz250x , broke it in , during my short break in ride after heat cycles the bike felt like it was running great . I haven’t ridden it since but I’ve added a lot of goodies . One being a fmf gnarly and silencer , what I want to know is will adding that exhaust call for a rejet ? I’m about 800ft above sea level
Yeh bravo company. I like stag myself lol
My Bravo Company upper sits atop a Stag Lower :)
THEY HAVE EFI NOW BUT I CANT AFFORD IT LOL
Damn.....I found your constant cut-in of your riding to be extremely disruptive in trying to concentrate on your instructional material. Found it so damn irritating that I could not make it thru....no new info here....anybody can follow a chart and make a few adjustments. Sorry....have really appreciated some of your other vids. Oh, hell, forgive me.....I've got PMS today.....
I recently bought a new 2015 KTM 250sx and right of the bat it didn't sound right in 1st and 2nd gear, it's almost like I wouldn't get the response I should have off a 2 stroke until I hit the power and in like mid 3rd gear so would doing this change things?
Power band*
It is certainly possible. However I noticed you mentioned it is a new bike. I'd certainly take it in to the dealer(especially if its under warranty) and let them know it doesn't sound right. If you have experience with small engines, let them know! They are more likely to dive into the issue.