ATV/Dirtbike Carburetor Jetting 101 Explained

KEEP ALL COMMENTS POSITIVE!!!!!
My breakdown on carb jetting

[@p.c.h.6721]

My engine wasn’t really working on the low, changed the needle by just one position and it was magical! Great video! Thanks a lot!

[@SparkysGarage]

Silvana H. Santos glad I was able to help

[@egn83b]

Big learning leap for a project engine I am doing. Have read a few books about carbs mainly automotive types but, This seems simpler and more straight foreword in the operation and more open source hardware. Thanks for the plug idea never took that into consideration in how the engine is working under load.

[@jamesmarze9850]

Thank you good information especially about the fuel mixture running leaner with more oil in it

[@SparkysGarage]

Im going to make a second part going in a little more depth and ill cover that.

[@georgeluther1409]

Sorry I was readin them backwards I have 270 Main and stock polite it runs good now and I bought a k&n air filture your videos really help!!!!

[@Taylor-Hanson]

This great video answers my previous question about jetting. Thanks again for taking the time to make such informative and interesting videos.

[@SparkysGarage]

Taylor Dean Glad I was able to help brother. Lots more to come

[@governor419]

Helpful video. Thank you. Needed a crash course in carbs/jetting and this was perfect.

[@hunterharkey1663]

Great video, needed some help with jetting and this is the video I needed!!

[@SparkysGarage]

+hunter harkey Glad it helped :)

[@quintonking1098]

Temp is currently 60 degrees and 600ft above sea level. Finally found that out so I hope this helps!

[@robothead1024]

great video! one of the best I've seen. what if I'm not getting start and everything is brand new?

[@SparkysGarage]

Thanks!

[@SparkysGarage]

lol, I wish they had vids like this when i started

[@Cav4ever]

I smell a video series 2 strokes for dummies lol i want the first series, another good one keep it up

[@p.c.h.6721]

Please help. I have my needle in position 5, super rich, that’s how my kart runs fastest. Should I change the pilot jet to a bigger one and then bring the needle down to position 3 or 4? Is my understanding that if the needle is in position 1 or 5, you should change the pilot jet to a smaller one or bigger one, so the needle position ends up in position 3, Am I correct? Please help, thanks 🙏

[@dblock2626]

I'm always stuck on something during this rebuild.. First I thought the hardest thing to figure out was shiftpawls and shit now I know this is gonna be the hardest thing.

[@connersnow298]

Awesome vid and edits and filming

[@SparkysGarage]

Much appreciated!

[@danieldemayo6209]

Awesome vid I learned a lot. You should do a vid on pros cons or fi vs carb.

[@Haithamsaadany]

outstanding video, I have a small question, regarding the bleeding holes on the pilot jet, when the holes are in the bottom means that a lean mixture and when they are up it means a reach mixture ?

[@SparkysGarage]

haitham saadany specifically for this machine and these carbs. The the air screw that covers the pilot jet controls air flow. Left or counterclockwise allows more air which is leaner.

[@vinnie1346]

Good job. Thanks for throwing that together.

[@DANKNUGREVIEWS]

hey man, i have a banshee with fmf gold series, the bike starts perfect. although the left side smokes alot and seems to be pushing more air than the right. previos owner said that that saide needed its carb cleaned

[@SparkysGarage]

340's should be pretty close to what you need. Throw those on and do a plug chop. You'll definitely need to up your pilot one or two sizes also. Thanks! :)

[@SparkysGarage]

Your decision. Extra cost, Extra speed. Pro's and Con's to both.

[@SparkysGarage]

Thanks so much man. Glad I was able to help a little.

[@scottbrooks3502]

Nice vid thanks bro tuned her up right :) crapy thing is I was on a ride and I felt a wobble my lugs were loose on one wheel look closer and my hubs tore up my rims I'm pissed : (

[@nboldman]

@Khiirraann290 the fine line between lean and rich where your perfect is better, but for my own personal reasons to make me feel safer i bump my jet up one more than the fine line which would make it rich.

[@SparkysGarage]

there is a huge list of things that could be the problem. Narrow it down, Fresh fuel. Clean the carbs. Check your jetting.

[@jeffreymonarrez910]

Great info man I really needed this for my banshee I might still need some help since I have mods on my quad

[@SparkysGarage]

Glad I could help

[@jeffreymonarrez910]

@@SparkysGarage when you’re talking about the air screw and saying “one turn out” is that a 180 degree turn or a whole 360 turn

[@jeffreymonarrez910]

I’m having a problem with my carbs I believe. I turn on my banshee and it starts reving rly high by itself at idle

[@SparkysGarage]

@jayshafer16 Advance the timing 4 degrees lower front sprocket

[@SparkysGarage]

One step at a time man. Jetting is simple.

[@SparkysGarage]

nboldman pretty much hit the nail on the head. A tad on the rich side isn't a bad idea... A fouled plug once in awhile is much cheaper than a new topend.

[@OGKILLa9365]

Screw this man I'm buying some 28mm Lectron carbs. Got tired of jetting this thing. It would be 85 in the morning, and get extremely cold at night and then it would run weird. Just gonna call it on the jetting and get the Lectrons, they're $1000 for the pair. Hope it's worth it

[@SparkysGarage]

@DANKNUGREVIEWS Do a compression check and check for leaks on both cylinders. Also clean the carbs. Check out my carb cleaning video!

[@shawn01707]

EFI is a great invention! If you are able to afford a quad new enough to have it this is why its worth it! More tiding and less rejetting

[@SparkysGarage]

Shawn p EFI is great. Expensive though

[@SparkysGarage]

Definitely throw some new plugs in it and see what happens. Post back and let me know.

[@gregmeloche2507]

Jet size on 04 blaster with big bore kits and full fmf exhaust.

[@SparkysGarage]

What intake and filter? Temp?

[@SparkysGarage]

By decreasing the compression of the engine. Larger domes.

[@Shawi7]

alright so i have a 270 main w/ 25 pilots needle is set either 3rd or 4th not sure however its the needle that came with my dynojet moose racing jet-kit. I run a k&n like yours w/ airbox led no snorkel toomey 5 pipes and as far as I can see its a perfect jetting set-up, the plugs have this nice tan-ish brown color runs great. I was wondering if i get rid of the airbox completely and install the pot k&n's with outerwears what should my main jet size be, 280&340 mains came with the kit i bought.

[@DANKNUGREVIEWS]

im sorrry man, im in a stuper on my banshee...i start her, she starts great.. but it seems like my left side smokes harder and pushes more pressure. and is even louder . but when i took it the the woods and a feild it was shredding like i think it should...its the only banshee ive rode.

[@devinmadsen2955]

I was on there but didnt see much but thanks alot man

[@DANKNUGREVIEWS]

it seems like the right side isnt firing consistently at idle..but when i give it some gas it starts firing.

[@asdf22129]

Hey man, thanks for the videos they have all been extremely helpful. I was hoping you would give me a little advice on my banshee i just bought. Its a 421cc, stage 4 head, stage 3 reeds, fmf exhaust, stock carbs, k&n filters air box removed, elevation (if it matters) around 800ft. I'm wondering which jets i should be running in it. 27.5 pilot? main? Thanks again for the videos and the help

[@305mcss]

Great video, Thanks

[@MegaDaDom]

What would you set the needle, main, and pilot at on a blaster with an fmf fatty K&N vforce 3 reed valve and open airbox

[@quintonking1098]

My Banshee was just rejetted with a 30 pilot jet, needle at the 4th clip, air screw at 1.5 turns, and 290 main jets. Mods are K&N Air Filter with no air box lid, FMF Gold Series Fatty w/ Powercore Silencer. Sunday it started bogging when it was supposed to hit the powerband. Plus my exhaust is only blowing smoke out of the left pipe when you tap the throttle, which I think is just a fouled sparkplug but do you think the powerband bog is a jet issue or air leak problem?

[@SparkysGarage]

You need to know what kind of head is on the engine. They are for sale on most major parts distributors. I think they are around 80-100 a set.

[@MotoBodega]

love the info bro keep it coming man

[@colemanwright8959]

What jet size is good for a 2005 660r raptor special edition with dg exhaust and k&N AIR FILTER.

[@topsecret6970]

great job man. one question what is your video on oil gas mixture called

[@SparkysGarage]

Ive seen that happen several times before... On a good note its a good excuse for some new wheels lol.

[@georgeluther1409]

I have a yamaha blaster i just rebuilt the top end,full fmf pipes, v force reeds ,I have a 610 main jet and a 350 polite jet. Can you help me it won't rev up like it use to can go as fast thanks

[@SparkysGarage]

Might wanna get some 330's 350's 60's 70's too

[@claytonhaske]

When changing jets for temperature change, do you go leaner, or richer with temperature drop??? Say you have a #100 jet @ 75°, what should you have for 35°??? Thanks, Clayton.

[@SparkysGarage]

claytonhaske You need a bigger jet (higher number) for colder temperatures. About 1 jet size bigger for every 20 degree temp change.

[@deathrain54]

my choke on my honda cr250r doesnt work and my bike doesnt idle. i even tightened and loosened the screw on the carb and it still doesnt work. do you know why?

[@jayshafer16]

what to do give u more bottem end and make it more snappy quicker throttle response

[@ToxicConfusionZ]

Good job man

[@SparkysGarage]

axleeater Thanks!

[@mr.re-store8857]

Hi
Great video :-0
Just one thing.. i think you said position one on the needle is the lower one towards the pointy end but i know from reading Mikuni tuning manual that #1 is the other end.

[@SparkysGarage]

It's been so long since I made this vid I don't remember the numbers. Just how they work. You're probably right.

[@BestBuzzHoneyBees]

Sparky...your vids are great. I was hoping you could assist me in trying to get my jets close in my banshee. I 've watched this Video a few times and I'd like to get your opinion on what my best option is.
Elevation is around 1200. Currently running full DG exhaust,trinity turbo mod head, K&N with stock air box...snorkel removed, vforce 3's.

[@SparkysGarage]

temp? Start at a 300 and a 27.5

[@BestBuzzHoneyBees]

SparkysGarage
temps when ridden are usually 60-90 deg.

[@SparkysGarage]

^those numbers should be about right then. Maybe a tad rich

[@anandblore10]

Sir I am using TVS Suzuki Shogun. Carb is Mikuni VM20. Stock pilot jet 20, main jet 100 and Needle jet size is 8 and needle position to 2. But for the performance upgradation, I installed pilot jet to 25, main jet to 110. After the trial I noticed that there was too much of fluttering and floods. Like the bike doesnt move freely in 2nd, 3rd gear and 4th gear. What should be the problem and how do I over come with this. Please reply or email at the earliest.

[@bradleymckinney83]

have a raptor 660 with full yoshimura exhaust , k&n filter with a modified air box, and a stock motor... should I buy a stage 2 or stage 3 jet kit?

[@DANKNUGREVIEWS]

thanks for all your help. do you think mabey a fouled plug could cause this? i switched the sparkwires and the same results..

[@mortym2982]

good video and got to ask you a question. ive looked on google and cannot find anything, so im hoping you can help. 01 kx65 with power core2 slip on, outlaw air filter and wiseco piston (stock) and carbon reeds (stock). its hard to start when cold and it wants to shut off when first accelerate. do you know what size jetting I need? thx

[@SparkysGarage]

I have no idea where to start on that for you. Most engines will not run will when they are cold. You should make your adjustments based on how easy it is to start, and how well it runs when warm. With these small displacement engines it is very hard for them to hold an idle when cold.
One recommendation is to buy one idle jet size bigger and one smaller. Try one, if it gets worse then but the one in that's two sizes in the opposite direction.
So lets say its a 25 (off the wall number). Then buy a 24 and 26. If it runs worse on the 24 then put the 26 in and try that.
Hope this helps.

[@MISTERR0BOT0]

very very helpful thank you

[@asdf22129]

Where would you start if it were for a 350cc. Maybe I can just go up from there?

[@SparkysGarage]

I would start at a 360 if the carb is stock and work your way down from there.

[@TheJonesPeople2]

I have a question, my 02 Banshee goes to through too many plugs than it should. I'll put in new out of the box BR8ES plugs in & after a few rides it starts to misfire and loose a little power. I stepped down from K&N pod air filters to a OEM airbox W/O the lid . I'm thinking I need a rejet what do you think? Thanks.

[@NobodyisEmo]

hello hope you can help me out!! i have a 99 banshee its got exhaust (toomey t5) reeds( vforce 3) open air box and k&n air filter fresh top end what main,pilot should i use from 70 to 80 degrees and 900 ft. altitude thanks for all the helpfull tips and vids

[@Khiirraann290]

nice video .. so whats better lean or rich?

[@alejandrosjoting6397]

Hopefully you can help me. 99 banshee was running and idles before I removed everything to paint the frame but I didn't do anything to the engine. I cleaned and rebuilt carbs with stock jet sizes , needle clip is on 3 but know it will idle for a couple minutes then die then wont idle without some gas. Banshee has torrs removal kit it has fmf gnarly pipes and fmf core 2 silencers, 32:1 mix, 2 K&N pod filters, carbs are synched maybe I can send you a short vid and you could let me know! Thanks

[@SparkysGarage]

Alejandro Sjoting Stock jets with aftermarket exhaust?

[@alejandrosjoting6397]

Correct 200.and 25 I bought some 310 and 27.5 but I havent had a chance to install yet

[@grenick85]

hey man I've been looking for help about jetting my banshee, we run the same oil 40/1, mine in mainly stock, bored .30 over with a long rod and full fmf pipes, k&n filter with no lid, riding in 70-80 degree weather? any idea of numbers for a main and pilot? right now my main is 260

[@SparkysGarage]

310 and 27.5 to start.

[@DKennison44]

Great vid man. I have a Question. I have a 2007 crf250r. It has horrible bog from closed throttle if I hammer it usually in like an idle or low first gear. If I roll on it will run like a bat outta hell. It only has a FMF slip on. And I redid the carb when I bought it. Did not know he did custom jetting. Now it has factory jets. Should I go up a few pilot jet sizes?

[@SparkysGarage]

DKennison44 Use the jet that is currently in it. Give it a full turn out and try it. If it gets worse then give it a full turn in. If it still isn't running right then up the pilot 1 one size and repeat.

[@appv12]

awesome video!!! Thankyou

[@SparkysGarage]

Glad you enjoyed it :)

[@SparkysGarage]

Only way to ride! :-P

[@devinmadsen2955]

Whats the best jets/jet kit and sizs for a 91 blaster 200, I have a fmf gold series header and turbine core silencer with boysen reeds and high compression piston, air box lid is off and im outting a kn air filter in it and gonna be running it in the winter 30-50 degrees, i run it at 32:1 right now, should i ad more oil for the winter or no? I watched the video but have no clue what it meant lol not to good with jets at all, id appreciate any help at all man

[@SparkysGarage]

Devin Madsen Do not change your oil mixture for the weather. Your best bet is to go over to blasterforum dot com and ask for jetting advice. Im really only familiar with the banshee and the blaster runs slightly different due to having a different cylinder size and exhaust design.

[@wagnerstrong]

I have a Yamaha Banshee with no air box Canon filters the bike runs out of top end too soon wondering if you could help it also has FMF pipes and the carb jetting is 280 Mains 27.5 Pilots and the needle clip is set in the middle

[@wagnerstrong]

k&n filters*

[@SparkysGarage]

FMF's are mid range pipes. I wouldn't expect a lot of top end out of them. The mains are what control your top end, try a size or two smaller if you aren't running lean.

[@11ste999]

Great vid

[@R6Ron]

if i go from 900ft to 1500ft should i go up a size on my main?

[@Joeak74]

Sparky, What altitude do you run your banshee at with a 27.5 pilot? Thanks.

[@andreablackburn4383]

i have a 22mm mikuni and my piranha 140 runs like shit its brand new what should i run for getting and air fuel mixture

[@SparkysGarage]

If its brand new and covered under warranty then take it back to where you bought it from. As for fuel air mixture check out my plug chop video.

[@DANKNUGREVIEWS]

Could you tell me what mm piston a .050 over is

[@juancastro8684]

I have a yamaha banshee currently with the air box removed, fmf pipes, but i want to install vforce 4 reeds and +4 degree timing. I just want to know that would be a good jet size to start with im also at 141" elevation and 100 degree weather almost all the time i ride my at.

[@SparkysGarage]

330 would probably be a good start.

[@SparkysGarage]

Not off the top of my head, I'm sure it can be found using a quick google search :)

[@bazure44]

well my banshee runs fine when i throw new plugs in it but ive been told i need to rejet because i have k n pods and i run my gas 50/1 is that too rich?

[@erosvielmas9949]

You think I should keep using racing fuel or should I go back to normal gas

[@SparkysGarage]

Glad the vid helped :)

[@SparkysGarage]

Prolly around a 350-360. Go bigger and work your way down

[@UniqueFreakk4You]

Ok so i never knew about rejetting, i always ran my yamaha blaster with no Cover under the seat that covers the air filter, but like 3-4 months ago i put on a fmf sst fatty pipe and a powercore 4 silencer (felt a slight change where it was more responsive when i pressed the throttle) and i plan on putting a k&n air filter what size jet screw thingys will i need.? if you can help. im 14 and just learning. and google hasnt helped me one bit. also my oil injector had broke, so manually mix my gas 32:1

[@SparkysGarage]

check out blasterforum.com Not sure on blaster jetting.

[@kyleheather0416]

SparkysGarage Ok i need help your video helped me alot but b4 i take apart my carb i want to be sure what i need to change i have a 2000 kx 80 has fmf gold pipe. Idol to 1/8 throttle is perfect after that it hesitates as i accelerate like its loading up on fuel and wot it takes a long time for the power band to kick in as i shift gears it falls out of the power band in every gear and has to work its way back into it i can't. Even lift the front tire of the ground. And it leaves alot of blue smoke i need to lean out the needle adjustment and main jet right ? Please respond

[@boom3boom2]

Hey man so my banshee is bogging down alot and won't hit powerband what do you think is the problem ?

[@kafepov7112]

I ha e a banshee with stock engine, stock carbs. I ordered pro circuit pipes, v force 4 reeds, k&n filter with pro flow adapter. The temperature here in Miami is mostly 80's and 90's and we're at about 8 feet about sea level. I was thinking 27.5 pilots and 330 mains. Any advice?

[@SparkysGarage]

Give it a shot and plug chop away!

[@erwingterry4953]

I have a 450 yfz do the pipe suppose to turn red it's been jetted it and it got a 3 mill

[@GametimeSlime]

Erwing terry yes, normal

[@SparkysGarage]

I am at around 1000ft if you're at 3500 feet then the air is much less dense therefor you need less fuel. Sounding like a 280ish should be about right.

[@GusgusA1]

I have multiple brands of quads. Could I get an assortment of each jet in each size? Are the jets interchangeable between carbs ?

[@SparkysGarage]

+GusgusA1 Most are not.

[@buckchapel1001]

Yes there are, you just have to get that brand of jets for that brand of carb

[@eacastillo00]

Sparky need help, my banshee has Toomey 5 pipes, k&n proflos filter and plate, .50 overbore engine, thing is i have bogging, more like a gurgling sound in 1/8 throttle, i checked my jets and the are all stock so i ordered jetts and needles i ordered 27.5 pilot, 280 main and ordered needles do you think my problem will get solved?

[@eacastillo00]

Also ordered a tors removal kit

[@SparkysGarage]

That jetting sounds very close to where it needs to be.

[@mikecallender7706]

When the temp drops do you go up on the jet or down on the jet ?

[@SparkysGarage]

When the temp drops you need a smaller jet.

[@mezz2710]

whats the go if i i have my fuel screw all the way in and only just starts to get a high idle, smaller pilot jet?

[@SparkysGarage]

Fuel screw all the way in means you cannot block anymore air, so you need to add fuel. Bigger pilot.

[@mustangmike04gt46]

great video bud. question tho.
got a 2014 trx 450r FCR carb with a Slip on Yoshi. stock main is 122. I tried 160,170 and 180 it ran the best. only concern is I have slight popping when down shifting. is it back pressure or to lean?
thanks

[@SparkysGarage]

+mustangmike04gt46 Idle jet is lean.

[@SparkysGarage]

+SparkysGarage or you have an exhaust leak

[@mustangmike04gt46]

+SparkysGarage
thanks for the reply bud.. yeah changed my pilot jet and cured the problem.

[@SparkysGarage]

Thanks :)

[@oherroprease207]

When the temp drops and you need to change your jet size, are you changing to a bigger jet or a smaller jet?
In other words does temperature drop create a more lean or rich condition?

[@SparkysGarage]

+oHerroPrease an air temp drop making air more dense and making a leaner condition. You need a larger jet for more fuel.

[@Cabral7o2]

Soo if I get a new air filter I have to change my jetting ????

[@SparkysGarage]

+Juan Cabral Not always, but most of the time, yes.

[@erosvielmas9949]

Hey I'm about to buy a banshee it's a Custom 421cc Cheetah Banshee but the problem is that it's Tuned to Run VP Racing C12 Leaded Fuel 108 Octane With 32:1 Two-Stroke Racing Oil how can change it back to normal gas get to me back ASAP thank you

[@erosvielmas9949]

And where are those located at and how much will it cost?

[@InksterLoyalty]

I have a stock banshee with k&n air filter not pods and toomey t6 exhaust about 600 feet above sea level in 60-80 degree weather what jets n need position do you recommend

[@SparkysGarage]

280-290 is a good start.

[@demetriusmedley9947]

Ok thanks man that's what I've been hearing

[@SparkysGarage]

Glad to help