How To Tell If Pilot Jet Is Rich or Lean [Jetting Symptoms]

[@MotocrossHideout]

Learn how to easily tune the air/fuel screw for the pilot jet circuit in just a few minutes: 2 stroke - motocrosshideout.com/carb/ 4 stroke - motocrosshideout.com/fuel/

[@williamlambie57]

A xpro titan 250 I bet it just can't handle it

[@zachzat1581]

@@williamlambie57I bet it can

[@EarthSurferUSA]

At 2:50, talking about a hanging idle. You mentioned the needle jet circuit (A higher rpm range than the pilot jet), and I think you meant the air screw, that helps control the fuel/air mixture for the pilot jet and the idle.

[@MotocrossHideout]

@@EarthSurferUSA Thanks for pointing that out. I did in fact mean the needle jet circuit. It's not nearly as common because, as you say, the pilot jet controls idle-1/4 turn throttle. However, I had a CRF150R that had a hanging idle when I was tuning the needle clip position until I set it to a richer position.

[@516chris]

1:12 that’s exactly what’s happening to me right now. I’m going to continue to watch the full video and probably will answer my question but should I up the jet or lower it?

[@MotocrossHideout]

Bad MPG? It's usually from a pilot jet that's too big (rich) or the float level is too high. However, how you ride the bike has a HUGE role when it comes to fuel mileage when trail riding. If you're constantly revving at a high RPM in lower gears, your MPG will be lower than average on any bike. Hope that makes sense :)

[@B7litz]

@@MotocrossHideoutis it possible for my carb to not have a air/fuel mixture screw? I can’t find one and think I just need to change the Jett to a different one

[@MotocrossHideout]

@@B7litz It's possible, especially if you have a "knock-off" bike/carb.

[@billyschannel997]

Great video and explanation

[@MotocrossHideout]

Glad you liked it, Billy.

[@nastysoda9212]

Thank you! I jsut switched to 100LL fuel and it's running rich, will bring the pilot jet down a size and see tomorrow

[@MotocrossHideout]

Yep, going to a higher octane gas will naturally make it run richer because it burns slower. Let us know your results! I'd recommend grabbing my free air/fuel screw tuning guide as well ;)

[@TalhaKhan-pi5tk]

best video yet fr fr

[@samcolletti4230]

Good to know on the blub blub symptom. Trying a rejet. Thanks

[@MotocrossHideout]

Let us know how it goes :)

[@str8mac842]

Real good video thank you I learned something today for sure

[@MotocrossHideout]

Awesome - thanks for watching!

[@Altanabstick]

Can you explain the difference between rich sputter and lean surging?

[@MotocrossHideout]

kzbin.info/www/bejne/i2rdq6egZp1pnpY

[@OG-sp4vs]

Just letting you know your videos are great very helpful now tell me if I'm getting this correctly im working on a DKW two-stroke 125 starts up perfect no problem there when I hit the throttle it bogs out so what you're saying it could be my pilot jet too rich? Thanks again for the videos

[@MotocrossHideout]

Glad you find them helpful :) Check out this video for more info on bogging: kzbin.info/www/bejne/i2rdq6egZp1pnpY

[@horvathhcsongor5664]

Hey there. My bike runs fine and everything but on full throttle it doesnt revs up to max as fast as it should. Main jet maybe?

[@rpilk26]

Same here

[@Dastardly_X]

Good one , Thanks 🤘

[@batu-mustika]

big bore need rich pilot jet or standard factory size pilot jet?

[@zachzat1581]

My bike runs perfect up to half throttle bogs out// misfires// backfires a little bit after half throttle to full throttle if you could do a video on main jet bog it would be great

[@austexledford]

Top endddddd

[@TheOfficialAnti]

Did he ever make the video ?

[@zachzat1581]

@@TheOfficialAnti idk

[@angelamartim8337]

Hey! Can you actually change the air-fuel ratio (or map) of a 4-stroke car engine too?

[@MotocrossHideout]

Yes, usually with an aftermarket tuner, depending on the car/system. It's usually not helpful/worthwhile unless modding the engine/exhaust/intake.

[@angelamartim8337]

@@MotocrossHideout Please bare with me as I'm not an expert and also from Brazil so I'm a bit confused about terminology here. By "aftermarket tuner" you mean a "professional scanner" ? Like those big devices that are plugged in the OBD2 system of a car? Are these two devices the same?

[@MotocrossHideout]

@@angelamartim8337 No, not a scanner. If your car is running poorly, I would take it to a trusted mechanic.

[@angelamartim8337]

@@MotocrossHideout Alright.

[@UpgradeAddiction]

you said that at both low throttle input, if it bogs, it could be Lean or Rich.. that doesn't help much.. lol @0:55 and @3:00

[@josipcrnkovic3296]

Yeah exactly what im thinking lol

[@MotocrossHideout]

Yes, but the sound and feel is different when it's rich compared to lean. Rich is a "sputtering" hesitation while lean is like the engine is dying or hitting the kill switch. Does that help?

[@jvnnis]

sick video!

[@andrews6739]

Excellent info! Too rich on my motorized bike.

[@EricTostes]

My bike runs ok when I turn the throttle gently. But when I turns is fast, the bike don't go. Looks like the clutch issue, but it is not, I have changed the clutch last week. Do you know if it can be carburetor?

[@MotocrossHideout]

Sounds like a possible jetting issue. Perhaps the main jet is too small, causing it to bog. kzbin.info/www/bejne/i2rdq6egZp1pnpY

[@gowengetter4599]

Completely agree with you mate. Good explainer video

[@MotocrossHideout]

Much appreciated, Gowen. Thanks for watching.

[@chrisrose2898]

Good stuff my friend! Thanks

[@MotocrossHideout]

Thanks, Chris!

[@bethanymarch-tf4bx]

Would the idle screw stop smoking when running or will the smoke still be there

[@MotocrossHideout]

Adjusting the idle screw will not stop a bike from smoking, if that's what you're asking.

[@bethanymarch-tf4bx]

@ so what do you think it could be if it’s smoking when started no oil in the barrel but it’s leaking from the exhaust on the head

[@MotocrossHideout]

It's a 4 stroke? If it's only smoking on start up and stops when it warms up then it's probably a valve seal that's leaking.

[@bethanymarch-tf4bx]

@ mine smoking all the time I think it’s the piston rings if it’s still smoking after I fix that then it must be the valves cheers do you have any other videos on how to fix them

[@MotocrossHideout]

@@bethanymarch-tf4bx Fixing the valve seals? No, sorry, not right now I don't.

[@infinitepawer]

WIll main or pilot jet ever become damage to the point that need to be replace ?? I wonder should I replace my 10 yrs++ jets or those jets will always fine as long as I keep clean it every once in a while ?? Thanks

[@MotocrossHideout]

What kind of damage are you referring to? :)

[@endastlur4788]

Hey man. Nice video you got here. I just recently got my first dirtbike. The engine is a Lifan 125cc 8,9hk four stroke, and the bike is one of these small chinese types mid size. It has been sitting from time to time since it was bought new at 2011. It has very low hours layed down on it, maybe a couple at most. It runs realy nice at all rpm but it hasitates when I go full power and go through all the gears on the straights. So every time I shift up and hit the throttle it kinda sputters or hasitates for a brief moment. It lasts not even a second, but it's easier to notice at higher gears. I suspect that it is a carb thing, but before I put the carb of I'm curious to what you think about it.

[@MotocrossHideout]

Congrats on your first dirt bike! Here's my video on a rich bog vs lean bog: kzbin.info/www/bejne/i2rdq6egZp1pnpY Yours sounds like it's running rich. I would try cleaning the air filter first. If it still hesitates, the main jet might be a little too rich if it sputters when you give it full throttle.

[@endastlur4788]

@@MotocrossHideout Thanx man. Your soundeffects are spot on 😁 I actually did screw the air/fuel screw both in and out, and other issues showed up that clearly was rich/lean rellated. But the sputter remained. Next thing will be checking the airfilter and probably also pull the carb of to see how it looks after sitting all these years. Thanx once again man!

[@infinitepawer]

Hi my bike original pilot & main size = 36 / 82 and engine will still running even if I turn the pilot all in so is that mean I need to up my pilot size ?? Thanks

[@MotocrossHideout]

If you're referring to the air screw, yes, if it runs best when it's all the way in or 0.5 turn out, then you need a bigger pilot jet.

[@davidleslie1957]

My 2 stroke is hard to start when cold when finally started and warm it starts on the first or 2nd kick. Also wont idle it wil stop. Wil a bigger idle jet fix this

[@darkogligorov3181]

I have 50cc 2 stroke scooter i cant adjust the card if i set it hight the idle goes hight and not come back if i set it low its go a litl hight then come back and its shot off so betwen that i cant fint it so what to cnange. Its a new carb and new piston. So maby is a jeting or what you think?

[@MotocrossHideout]

Hard to know without more info. Sounds like it might be lean on the pilot jet/air screw or possibly an air leak.

[@darkogligorov3181]

@ i put biger jets now its run good its has a good idle. But on the litl throtle like its hesiteting then you give a litle more then its going. I notice i was like litl close to half throtle its was going a good then give a whole throtle and it hesiteting like 2 and a half second then its punch it. Is it the air filter i didnt cleen it like 4-5 monts or its lacking more fuel or somethink like that??

[@bronco_4.3]

My sp400 will idle great but if you give it barley any throttle it revs up then if you go anymore it cuts out will pop sometimes any ideas?

[@SpACeCruizeR2o3]

Too rich or jet is clogged most likely gotta get that carb off start from the beginning check the gaskets ect spark plug and cdi wires

[@Altanabstick]

Hi! I have a 98 WR400 with a 450 carb. It did not respond to the mixture screw and did not die when fully seating the screw. I changed the pilot jet from the stock 48 to a 45 to a 43 to a 40 to a 38 to now a 35, HUGE change. Now it responds to the idle screw, 2 turns out seems best. It does not sputter when lugging the engine in high gear but it sputters bad with just a bit more revs and a small throttle opening. Wacking full throttle feels perfect. It backfires quite a bit from half the rev range back down to idle. I am confused. Can a 35-38 idle jet be right? And should I also lower the needle to remove the sputter when cruising?

[@MotocrossHideout]

That sounds smaller than it should be. What is the float height set at?

[@Altanabstick]

@@MotocrossHideout I lowered the needle to make it lean, and suddenly it wouldn't start anymore. I have the suspicion that the needle doesn't close off the orifice at the mid position, causing the needle to influence the pilot circuit. It started fine at idle 35 needle 0 but won't start at idle 35 needle -2 leaner. I am now at idle 40 needle +1 richer and it fired up again. Still need to ride to test whether the rich stumble has become worse or better. I have the feeling that the needle doesn't close the orifice at the mid setting, which influences the pilot circuit. Making the needle -2 leaner closes off the orifice and because of that it won't start. After I am done testing the needle +1 richer position I want to revert to idle 48 and needle -2 leaner to see if that starts and removes the rich sputter at small throttle openings. If that is the case I theorize that the needle doesn't close off the needle tube at richer settings which influences the pilot circuit by adding fuel through the needle orifice. The float hight seems to be parallel with the bowl gasket

[@MotocrossHideout]

I would recommend measuring the float according to what the OEM service manual says. Sometimes parallel isn't always right, I've found. Also, if you have the stock needle, I would probably go back to the stock position and then figure out the pilot jet and fuel screw setting first because that's the most critical for starting, idle and up to 1/4 throttle. If the pilot jet is more than 1-2 sizes bigger or smaller than stock, then I suspect there's another issues causing it to be too rich or lean, if that makes sense.

[@Altanabstick]

@@MotocrossHideout That makes sense. A 35 pilot does not make sense. I will check float hight conform manual tonight. Btw, just tried riding with a pilot 40 and needle +1 richer and it was a stutter mayhem, 35 and needle at 0 also had bad jitters but has been the best so far. I have no idea what my rich issue could be. Next step is a new sparkplug, checking the float height. If float height is normal I am going to try the stock needle at -1 leaner with 40 pilot, and 35 pilot, and 48 pilot. I'm kinda lost

[@Altanabstick]

@@MotocrossHideout Checked float height, 8mm conform spec which is parallel with the gasket. Reinstalled everything with needle -1 leaner and pilot 48. Kicked to life without choke. Strong smell and eyes were burning. Installed 42 pilot kept needle at -1 and went riding. Starts with choke, ran best with idle screw seated and stutters at small throttle openings. Shut off after 10 mins, didnt start again and had to walk 40 mins home. Gas was flowing out of exhaust when kicking. Back home, turns out overflow is clogged, gas came pouring out of intake manifold. Seems my float needle is shaking or something and doesn't work when bike is running. Going to test with transparant tube on overflow to see gas level in carb while bike is running. Gas level right now (using transparent tube to measure) is about 10mm above gasket at the main jet. Is this too high or not? It is currently not overflowing.

[@D_gas_bob]

What if it starts and runs fine, but has rapid backfire when decelarating?

[@Cookiemonster2m]

lean i allways thought it was rich but its lean with one of the jets

[@D_gas_bob]

I got it working ok, but air screw is 4 turns out, when it got hot I had low speed flutter. I noticed the plug rich as well, I went back to stock and reduced the pilot and the original main, flutter gone and air screw at 1 1/4. I'm done, hard to pull carb, frame in the way... Great video.

[@nohesinick5492]

Sounds like anti lag for a turbo 😂

[@Porter-555]

My cousin had this problem and his was the electrical on the carb this may not be the problem

[@OldMinecraftIsBetter]

Lean

[@germanthiccboy4139]

So if my bike is both my bike will bog and will not idle, it will can take forever to start and be extremely hot immediately

[@MotocrossHideout]

Sounds very lean - either carb/pilot jet is too dirty it needs to be richened up.

[@germanthiccboy4139]

@@MotocrossHideout it’s a brand new carb so should I make the number go up or down ?

[@MotocrossHideout]

@@germanthiccboy4139 Richer = bigger. Before that, I would try adjusting the air/fuel screw. Grab my free guide in the description so that you can know if the pilot jet needs to be changed.

[@jonathanheiny7300]

Also check for air leaks around manifold and carb

[@shaakirmir6722]

Hey bro need advice, I got a 125 2 stroke with oil injection. My bike smokes quite a lot on startup and leaves a black trail of oil out the silencer with every ride. The oil pump settings are factory and I’m coming to the possibility of the pilot jet being too rich?

[@aleksanteri1234]

Recently my tempature light came on, and then it just turned off. i looked at the spark plug and it was running way too rich. I have no idea how it started running so rich all of a sudden (started to spew oil everywhere from the exhaust) maybe my choke is stuck, or some seal has broken and allows oil to my motor that way?

[@kylepapke9357]

Currently trying to tune my mikuni vm22 on predator 212 and if I slowly get into throttle it dies immediately but if I snap the throttle a few times to get me to around 10 mph it wants to go then, have new main jets coming in the mail tomorrow and I’m debating on getting a new set of pilots screws as well Any recommendations are greatly appreciated 😅

[@MotocrossHideout]

Hmm, sounds like maybe the pilot is too small (lean) if it dies at 1/4 turn throttle.

[@caliman823]

I'm in the same boat. I have to put the needle in the richest setting so it doesn't bog and die on me. I have polit and main jets ordered. Just going through the process of learning to tune carburators.

[@Alejandrof2006]

My 2001 yamaha blaster 68mm big bore stroker 3mm starts first kick hot and cold but when i give lil throttle starts to bogging

[@caitlinnovak9497]

Hello, my bikes bogs down at low throttle and then higher rpm’s it comes back to life and it’s blowing smoke, is it showing signs of too rich or lean??

[@MotocrossHideout]

What does the bog sound/feel like? What bike?

[@DaRealG2Productions]

I finally got my bike started but for some reason the exhaust starts to glow red from overheating and im not sure why? I looked it up and it says my carb is too lean but i have a aftermarket carb and im not sure where the air and fuel jet screws are exactly. Any advice or tips?

[@MotocrossHideout]

It could be lean, but liquid-cooled 4-strokes can overheat quickly if you let them idle too long. The fuel screw on a 4-stroke is typically on the front half of the carb and underneath (near the front of the float bowl), but it depends on what bike you have. The screw is small and usually requires a flat blade to adjust it.

[@evankufahl2309]

Hey I just picked up a kx112 and it starts 1st or second kick when cold and hot but sputters pretty good right before the powerband and then smooths out. What do you think could be the issue? Also it doesn’t like to idle (even when hot)and sort of seems like it hangs but I’m new to two strokes and can’t really tell. Any idea what’s going on? Thanks!

[@stepanrais5534]

rich main jet ?

[@dyingzombies3073]

I currently have a vm22 carb with a air filter on a predator 212 with a 98 main jet even with a 115 main it shoots blue flames when accelerating but not at idle and no matter how much it is tuned has blue flames how can I fix this ?

[@MotocrossHideout]

First two thoughts are: There's an air leak (around the carb or the exhaust), or the float height is set too low.

[@Ifeelgreyt1738]

Hey man, I have a 1998 yz125 and I wanna trail ride it but I don’t know what fuel ratio to run it in and it’s really rich right now wondering if you can help me or give me tips.

[@jaydenriley6739]

Yz's usually run 32:1 and if it's rich them wind out the air screw a bit till she runs right

[@MotocrossHideout]

Yep, Jayden gave some great advice! If you need help with tuning the air screw, grab my free guide here: motocrosshideout.com/carb/

[@vijayam1]

Brilliant one as always!

[@franzgutowski2980]

I got my bike to idle and start well, but it bogs and seems to want to take off but does not. Is that rich? I have the idle knob all the way in and the idle air screw 1.5 turns out. I am at stock jetting but at 5000' elevation. Any guidance would be appreciated. TIA

[@MotocrossHideout]

Idle knob all the way in is a sign that jetting is off. Probably too rich on the pilot/air screw. Higher elevation makes bikes run richer due to less oxygen in the air. Did you grab my air screw tuning guide? :)

[@franzgutowski2980]

@@MotocrossHideout I put pilot and main jets 2 sizes smaller. 50 and 128 respectively. Bike still idles and starts up fine, seems ok at 1/4 throttle through the neighborhood but won't get up and go still. Stock jets were 132 main and a 55 pilot which matches what was in the book. I did turn out the idle knob now. It's not maxed lol. I was thinking of adjusting the clip on the needle one up (leaner). I did request the guide but it didn't come through my email. I saw several places that said a jet up or down is good for about 1500-2000' of elevation and at sea level it's recommended to go one size larger so at 5000' I thought 2 sizes smaller from stock would get me in the ballpark. Am I on the right track? I did have another generic carb (Miura) that came with a 115 main (it was stamped 115) and the bike would rip on top. The pilot jet had no stamping on it. Maybe leaner yet? TIA

[@MotocrossHideout]

@@franzgutowski2980 Yeah, I would probably go leaner. Just make one change at a time. Start with the pilot jet/fuel mixture screw. If it keeps getting better than you're on the right track. As for the tuning guide, check your spam folder, otherwise let me know!

[@franzgutowski2980]

@@MotocrossHideout Hi, thank you for your patience and guidance. I went 2 sizes smaller on the main jet and it's still popping and bucking; the shop I went to buy the jets said to put the needle back to the middle. It was about the same so I slid it back to the top. It's better but still bucking and popping. I was going to get 2 more smaller. What do you think? How much difference is going 2 needle notches? I think it's 1-2 jet sizes it seems like. I also noted that I am opening the throttle to get the bike started. Should I go a bit smaller on the pilot too? The transition from 1/4-1/2 throttle seems to stumble. Is that pilot jet or main? TIA

[@MotocrossHideout]

@@franzgutowski2980 First, only focus on and make one adjustment at a time. I would work on the air screw first since that's the most important for starting/idle/low-end throttle response. Is all of this a new problem or has it always been like this?

[@HDkillerstar]

My bike starts after 5-6 kicks, idles great but once warm I have hanging idle (takes a second to get back down) and then tends to bog on the first blip...high rpms are great. I am running a smaller main jet but a bigger than standard pilot jet...do i need to go even bigger on pilot?

[@MotocrossHideout]

What bike? It could be an air leak. If it's a 4-stroke, check fuel screw o-ring is properly seated, and that the hot start isn't stuck/broken/missing o-ring. Also check carb clamps are tight and the intake boot isn't cracked.

[@HDkillerstar]

@@MotocrossHideout Understood, when its cold it runs fine, all power bands are good except once its warm it tends to bog on that first blip, pilot circuit feels lean. Ive spend a decent amount of time rebuilding these carbs (723A Keihin on a 73 CB450). I think the O rings are good, the boots are old but dont seem cracked or anything, it could just need replacement

[@MotocrossHideout]

​@@HDkillerstar Interesting. Usually, it gets richer as the bike warms up. If there's a lean bog after warming up, that brings to mind an electrical problem. Whether it's a bad wire/connection/ground, or a bad CDI. Not saying that's your problem, but just something to be aware of.

[@HDkillerstar]

@@MotocrossHideout understood, Ill check all the connections again...especially the coil etc. Also comes to mind this issue got worse after using 91 octane the past 2 times

[@WestHaddnin]

What if it sounds like rev limiter after 1/4 of a throttle?

[@MotocrossHideout]

Rich sputter.

[@matthewlucarelli49]

Would it be safe to assume that I'm running rich if I'm just completely lacking mid to top end power? In 1st and second it has its initial pop . Half way thru second it seems to not reach it's potential. Seems very sluggish . 22' 150sx

[@MotocrossHideout]

Hard to say for sure, but it sounds like that might be right. Try going down a size or two on the main and see if it feels better or worse. Make sure the air filter is clean.

[@matthewlucarelli49]

@@MotocrossHideout thanks man, your videos honestly helped my scrambled egg brains figure shit out. Figured her out after work today, running crisp !

[@MotocrossHideout]

@@matthewlucarelli49 Awesome, glad you got it running well, Matthew!

[@antonionegrete33]

I was driving my 93cr 250r today and I was going to stop and I pulled the clutch and came to a stop and it just died clutch is good won’t start good compression good gas flow idk what’s wrong

[@ALLCITY402]

My yz80 only idles with choke on soon as I try to turn choke off bogs down and dies lots of smoke

[@kenmartin2454]

Please help. Im confused. I bought a Yamaha yz250f 2007. Came out the shop 20 hours ago. It starts very easy cold, 1-3 kicks and idles good. When i pull the choke out it revs high. Also when i throttle it when cold it has hanging idle. When i ride it it gets the rich bog where it hesitates whenever i give it gas, it happens eaven in 4rth gear high rpms but not so often as in the middle revs. Also when it gets warm it WILL NOT start unless i give it throttle while i kick it, then its a first kick start. Also it doesnt idle when hot. But weirdly today after heavy riding it randomly idled when hot. Which is rare.

[@MotocrossHideout]

Sorry to hear about your issue. A hanging idle is usually caused by a lean fuel screw/pilot jet or an air leak (loose clamp/cracked intake, or missing fuel screw o-ring). I recommend grabbing my free fuel screw guide and starting there. Let us know how it goes!

[@markcoyne5811]

Iv got a 70 kit with upgraded carb can get it to idea and sit there, but when riding soon I come on to power band it sputtering like made

[@MotocrossHideout]

Sounds like the main jet might be too rich/big.

[@ronnierebel6388]

Hey my bike Boggs out at full throttle and won't allow me to go faster does that mean it's too lean

[@MotocrossHideout]

See if this vid helps more: kzbin.info/www/bejne/i2rdq6egZp1pnpY

[@mysticalmisfit33]

Got a 1990 dr250s, just cleaned the carb, replaced air filter, cleaned out the gas tank… I can only bumpstart it and when it’s running, It’s giving me the to lean symptoms… Any pointers?

[@Peyton_Edwards]

He doesn't mention your float bowl has to be the right height. Your pilot number size up or down. Intermittent spark.

[@jacobgore8978]

I got a crf250 my bike hard to start sometimes it back fires and pops and it dont idle what do you think it is

[@MotocrossHideout]

Sounds like it might be running lean. Either needs a fuel screw adjustment or the pilot jet circuit cleaned is my best guess.

[@jacobgore8978]

@@MotocrossHideout ok thank you for the reply turns out bikes was sat for a couple of months

[@MotocrossHideout]

@@jacobgore8978 Gotcha, yeah pump gas can go bad in a matter of weeks. I recommend using gas with no ethanol so that it lasts longer without causing carb problems.

[@lucasclouthier237]

Mine and my wife’s 4 stroke has a very slight sputter in the very top end when pinned what could I do to remedy this ??? It only happens when pinned also bikes are harder to start after riding for awhile ???

[@MotocrossHideout]

Hey Lucas, sounds like they're running rich. First, check if the air filter is dirty. If they're full of dirt/debris, that makes it run richer because less air is getting through the carb. If that's not the problem, then the main jet might be too big and you could try going down a size or two. There are many other things that could cause this, but those are probably the first two things that I would check.

[@lucasclouthier237]

@@MotocrossHideout it was definitely dirty air filter cleaned them up didn’t have the issue thanks again

[@emis.2217]

how about pingin ,What would it be then? I have a KTM 300 EXC 2013 and when it gets very hot the idle comes back harder and pings

[@MotocrossHideout]

It's usually caused by using gas with too low of an octane rating (or perhaps if the gas has sat too long). A KTM 300 should be using 91-93 octane if it's stock. If it happens to have higher compression than stock, then you'll need to mix or use higher octane gas to prevent detonation (pinging), if that makes sense.

[@emis.2217]

@@MotocrossHideout something like this I didn't think about for half a season I changed the cylinder head with one of S3 Enduro something like lower compression but in reality it is higher than what stock , And before it was going perfectly I'll try a higher octane mix thx

[@MotocrossHideout]

Sounds good, let us know your result!

[@svampv]

Whats the problem when the bike is hot and the idele is high, and when you rev the engine the idele goes down??

[@MotocrossHideout]

A hanging idle? The idle is slow to settle? kzbin.info/www/bejne/pWO7XqGGibhoprc

[@svampv]

@MotocrossHideout its hanging after the ride, and then you rev it, it goes down. If you understand, my english sucks

[@MotocrossHideout]

@@svampv No worries. Did you check out that video that I linked? kzbin.info/www/bejne/pWO7XqGGibhoprc Those are the most common causes of a hanging idle I've run into.

[@svampv]

@@MotocrossHideout thank you

[@Bieggaoaivi]

My pilot is just to big, can i just move back to the one i had and just add higher octane gas? the one i had was just a tad to lean, and there is no pilot jet between those.

[@Nate-hw1oe]

You have to tune it properly then

[@usanafusion]

So i have a 2019 honda crf 125fb and when i start it after a couple seconds it starts to act like it wants to die when idleing and not getting to its full rpm and sounds very weird and slow ever since i replaced the spark plug

[@MotocrossHideout]

2019, so that's EFI. If it did that only after replacing the spark plug, I would look into that. Did you use the correct plug, is it properly seated/tightened? Is the plug cap pushed down all the way onto the spark plug itself?

[@usanafusion]

@@MotocrossHideout Yeah i mean all of that is done but still does it… Could it be because I used a different spark plug brand that i don’t usually use?

[@MotocrossHideout]

@@usanafusion As long as it's the correct size, type, and heat range for your bike, the brand shouldn't matter.

[@problemx3526]

My bike dies when idling hot, I screwed it richer and it worked but now in my way to the gym it almost drowned itself when starting from a intersection so too rich (2stroke bike)

[@purebrediggy9150]

What does it mean when I'm cruisin, then my bike suddenly loses power and is hard to start back up again?

[@MotocrossHideout]

Hard to know for sure without more details. If it's liquid-cooled, is there still coolant in the radiator? Have you done a compression test?

[@__215xalbert__]

I’m having a problem, I can rev all the way when I’m in neutral, when I’m going the the gears power band does not exist it’s like it’s hitting the rev limiter way to early

[@MotocrossHideout]

Sounds like the main jet might be too rich/big. Also make sure the air filter is clean with the proper amount of oil.

[@__215xalbert__]

@@MotocrossHideout I did a carb rebuild with proper specs, before I did that I definitely had to much oil in the gas, air filter might be a tiny bit dirty

[@Kevin-j9c1l]

If you have to turn the mixture screw to far out you need a bigger pilot jet. And smaller if turned in all the way.

[@MotocrossHideout]

You're welcome, thanks for watching!

[@p4nd4Z66]

My bike (KMT EXC 400 07) runs basically perfectly but i have one issue i cant solve, its popping flames on deceleration.

[@MotocrossHideout]

Has it always done this? What have you tried so far?

[@p4nd4Z66]

@MotocrossHideout its always done this i have tried changing smaller and bigger main jets adjusting the needle Up and down. The exhaust has been sealed from where it leaked and the valve clearances are checked. Carb completely cleaned probably 20 times. Checked for air leaks

[@MotocrossHideout]

@@p4nd4Z66 What/where all was checked for air leaks?

[@p4nd4Z66]

@@MotocrossHideout Every intake pipe new airbox. exhaust

[@MotocrossHideout]

@@p4nd4Z66 Have you checked or tried adjusting the fuel screw? If it's a little bit lean or the rubber o-ring is hard/cracked, I've had similar problems on other 450s.

[@Jermain3_]

My cdi box broke yesterday is it because iam riding with no battery in my bike?

[@MotocrossHideout]

What bike? Did you remove the battery?

[@offroadracing]

have 2004 ktm 453cc with 41mm carb has low rpm bog past half throttle

[@MotocrossHideout]

Is this a new problem? What have you tried so far?

[@offroadracing]

have had problem for over a year jetting is 162m 40p ocemr needle 5th setting down

[@MotocrossHideout]

So once you reach around half throttle it bogs? Does it sound like the engine is dying, or is it more of a sputtering/hesitation? The needle clip is at the bottom (or 5 out of 6 down)? Have you tried other clip positions?

[@offroadracing]

feels lean when throttle opened quick sometimes will even stall if slowly rolled on throttle it runs good thinking its accelerator pump will try 7th setting

[@MotocrossHideout]

@@offroadracing Okay, not sure your elevation/climage, but I wouldn't think it should be that lean on the needle clip. I would definitely test/make sure the AP is working/timed properly because that's a huge culprit that I've had to fix on multiple FCR carbs. See if this vid helps: kzbin.info/www/bejne/h2XGmaaunayLsJacttps://kzbin.info/www/bejne/h2XGmaaunayLsJY

[@Shane7787-b7w]

im getting hanging idle on my kmx 125 i raised the throttle needle and that made it a little better than it was but still hanging any idea anyone?

[@MotocrossHideout]

Have you tried adjusting the air screw?

[@Shane7787-b7w]

@@MotocrossHideout yes mate its 1 and half turns out it dont have a seal and the washer whats supposed to be on mixture screw but doubt thats causing the issue

[@MotocrossHideout]

That could definitely be causing it. If there's no seal/o-ring on the air screw, air can leak past and cause it to run lean and give you that hanging idle. I'd fix that and see what happens.

[@williamlambie57]

My dirtbike will bog from idle if you snap it to wide open throttle.... if you easy it off idle then wide open throttle it will rev freely. Brand new carb and jets! What's going on here?

[@MotocrossHideout]

Hey William, what bike? It could be the main jet that's not perfect sized, but if it's a 4-stroke that doesn't have an accelerator pump on the carb, sometimes they can't handle quick WOT.

[@ConnerGee-h8n]

@@MotocrossHideoutI am having the exact same issue. I have a 2002 Yamaha TW200 and I just put a 28mm nibbi Carb in it with a new throttle cable. I can adjust the air screw and idle screw to get it to idle properly but if I snap the throttle wide open it almost dies or does die. If I adjust the idle screw and air screw to idle a little high then it doesn’t bog when I snap the throttle. I was thinking I need to put a bigger main jet in or can the bike just not handle 0-100?

[@MotocrossHideout]

@@ConnerGee-h8n WOT has to do with the main jet, but most dirt bikes that don't have an accelerator pump can't handle 0-100 quickly, especially if you're just revving in neutral (not a practical test anyway).

[@Duch125]

Same problem with a 03 xr125l. It almost dies on low rpm if i give it full gas. If i open it 1/4 of the way to 2k rpm it has no problem with full gas, the bog's stronger while the engine is cold.

[@MotocrossHideout]

@@Duch125 Most engines bog when cold. If it bogs when you give it full throttle, that would be the main jet.

[@hetfeestcartel6769]

So mine does all of the above....help..really...help..

[@MotocrossHideout]

Start with the air/fuel screw and make one adjustment at a time or else it will get confusing. Grab my free guide to learn how in just a few minutes and then let us know how it goes :)

[@hetfeestcartel6769]

@MotocrossHideout Thnx for the reaction :) i already downloaded the pdf like a month ago. After all that Still having a contradicting issues... The carb that i bought is a Nibbi pe24 (flange) it comes stock with a 112 main and 40 slow jet, the gas needle is on the 3rd position (i went back to this stock setting). The bike brand is an Orion Apollo RX50 with a 125cc zongshen standing block, also i have the stock airbox/filter on it. I life in The Netherlands and where im at im straight on sealevel (it heard that it matters jetting size hah) When i give it between start and a quarter throttle it bogs (blehhhh) and dies completely.. if i come off the gas it will idle but after a minute or so it will die out of itself. Sparkplug is black not wet wet but a little shiney. I hope you or somebody can give some advice

[@hetfeestcartel6769]

Before i forget. Whenever i get it to run and start driving like 4 minutes the engine dies and i cant get it to start for like 2 minutes

[@MotocrossHideout]

Sounds like it's running rich if it's harder to start when hot. I would try at least 1 size smaller on the pilot jet and see if it's better. Also recommend checking the float height if you have the float bowl off.

[@hetfeestcartel6769]

​@@MotocrossHideout Again thnx and i did all that. The float is level. I tried all possible combo's, first only the pilot jet later on the main jet... just like you said not all at once. Note the exhaust also backfires when releasing the throttle with the new and old carb.... could this be more then a carb problem? like valve spacing/clearing? (its a fourstroke) or something like low compression at the piston? maybe some people overhere have an answer to this?

[@johnnyrobertshouston2341]

My bike starts and idles high and won’t go down and I can’t give it throttle or it dies

[@MotocrossHideout]

Sounds like a clogged pilot jet if it's been sitting for at least a few weeks or months.

[@pikzzzlerkerll5247]

Why does bike start only when air screw is tighten?

[@MotocrossHideout]

As in, zero turs out? Sounds like it needs more fuel = bigger pilot jet.

[@jeffwendorf170]

Just put a fresh top end on a 15 husky te 125 , now it will only start with the throttle wide open, I cleaned the carb twice throughly

[@MotocrossHideout]

Hey Jeff, sounds rich. Have you tried adjusting the air screw? Make sure your carb float level is set correctly and that the reeds aren't cracked/worn.

[@jeffwendorf170]

excellent thank you for the feedback sir, I will check all the above

[@kjois6198]

So how to tune rich pilot jet ?

[@MotocrossHideout]

Start with the air/fuel screw. If you want to learn how to do it in just a few minutes, grab my free guide in the description and let us know how it goes.

[@choppergirl]

Nonfunctioning Carbs have turned my love of motorcycle into absolute h8tr3d. When you've taken the same one apart, cleaned it and every jet and passageway and hole and seal, put new parts in it, checked everything, 50 times and put it in and out of the bike with no significant improvement... Carbs are the worst POS ever.

[@MotocrossHideout]

Sorry that you've had so much trouble. I replied to your previous comment on one of my other videos. What bike do you have? 4 stroke?

[@xxs1lentk1ller30]

I changed my pilot jet from 40 to 32 and now when i touch throttle it just dies

[@MotocrossHideout]

Not sure what bike you have but that's a huge jump down (3 sizes, which is a lot for a pilot jet). Why such a big change?

[@xxs1lentk1ller30]

​@@MotocrossHideout thanks for quick answer, my bike is alfarad 250cc on nibbi pe30 carb i had issue when i put on choke it just died same after more than half throttle so changed it to 38 pilot better but still bad 35 better but dies a little 32 was the best but ye now this issue

[@MotocrossHideout]

Gotcha. It sounds to me like the engine isn't fully warmed up because you shouldn't leave the choke on while riding. Once the engine is fully warmed up and the choke is off, the bike should be able to idle, and then you can make accurate jetting decisions, if that makes sense.

[@xxs1lentk1ller30]

​@@MotocrossHideout ok thank you, i tested on 35pilot and got weird issue with very hard starting and extremely high idle on choke but dies without

[@MotocrossHideout]

It sounds like it might be lean. Make sure there are no air leaks (caused by loose carb clamps or cracked intake boot). I would probably try the 40 again and keep it running until the engine is fully warmed up so that it will idle and run without the choke. You may have to adjust the idle screw.

[@lw3918]

Just buy a newer bike that's fuel injected.