2-Stroke Jetting Basics and Carb Tips

[@JacksonD489]

You’re the man, Jay! It’s a blessing to have someone knowledgeable willing to put this information out there… Cheers to you!

[@matthewnorris203]

I really like watching your videos. You’re straight to the point without any dramatics. I appreciate that.

[@jondoe4667]

I love how those rm's looked. And the rm250 in that gen is one of the best handling bikes you can get in my opinion.

[@townsendYXZ]

Never heard of that little compressed air trick at the end that was pretty neat will be putting that in my tool box.

[@jimmyneutron6127]

Id like to know when a bike comes to you, how you diagnose that you need to adjust the carburator. Then how do you diagnose when to charge jets. Reading a plug exc

[@carsonpoole5873]

Excellent channel, best in the business

[@Workerbee-zy5nx]

I learned stock to begin with at normal altitudes, then the higher up the jetting needs change, or temp and air density changes dictate. I do it in 1 step increments.

[@Natedoc808]

Replace all philips heads with torx or even allen heads on your bowl and slide cap. On these older bikes, it's easy to tear/crack the intake boot by turning the carb to access it, just loosen the sub-frame, pull the silencer and swing the sub-frame w/ intake boot up off the carb, then pull the carb. It's often hard to find replacement air boots for these badass older bikes, and if you do it's expensive. 15lb monofilament fishing line works great for cleaning out jets, as does an air needle like you use for airing up a football/basketball.

[@matthewnorris203]

When you started it, I got a big smile on my face 😊 Also, VESSEL JIS screwdrivers. They’re AWESOME. No screw stripping

[@JimEckert]

Now I can finally go through mine!

[@spencerclark2269]

Awesome jetting tips 🎉🎉

[@mgtowlevel5293]

Look at this guy straight to carburetor tuning without a warm up.

[@bradmckinnon945]

Legend mate! This helped me out a lot today 🙌💯 appreciate the content!

[@Dirt_Bike_Dave]

Thanks Jay...you can never have to much info on doing the jetting .

[@jcbenson01]

I was hoping for some plug reading and discussion about plug chops.

[@grampaeasysmachines207]

Great info. Thank you sir

[@TheCarlejoseph]

Thanks for the tips. Jetting can be a pain.

[@jondoe4667]

I feel like I'd have a better chance of building a jet than correctly jetting a carburetor. I've been spoiled with my fuel injected CRF. But I picked up a CR250R so I'm sure I'll be pulling my hair out trying to jet it.

[@e.rtraining7711]

Nice clear video. Quick question. When you were putting the needle back in the carb, there is a small nut that locks in the needle. I’m looking in the RM 250 manual and it shows a small spring between the nut and the needle. Couldn’t see if you had that?

[@dirtbiketv1]

If you have tech questions or want any assistance from Jay/DBTV1 you will need to send an email. Its easy to find on from our website www.dirtbiketv1.com we do not list it on here to reduce scams etc.

[@Natedoc808]

I didn't see it either, but yes there is usually a small spring or spring washer

[@dougb2091]

Thank you Jay. Very helpful on my 99 yz250 getting dialed in after carb rebuild. The challenge is idle adjustments since it's done with choke on a Keihin.

[@billbright1755]

A carburetor can only preform as it is pre programmed. Proper fuel to air ratio for combustion across the rpm spectrum of the engine. The more carburetors the more potential for a mistake in tuning. Altitude extremes can cause necessary jetting changes. Also oil premix ratios. More oil means a leaner fuel mixture as oil not nearly as combustible as gasoline. Ethanol is junk foisted off by Congress and is to be avoided in racing engines.

[@crash86ed]

I was always told never to use wire to clean jets as it will gouge the brass inside and you now have richer jet. Be gentle :)

[@Perceleable]

Well brass parts are quite resilient against some copper wire.

[@MotoBailey]

Sometimes making it bigger and richer is better for the smaller machines

[@Natedoc808]

i use 15lb monofilament fishing line.

[@78raarons]

6:59 Guitar G/B string works great for cleaning out jets..

[@EarthSurferUSA]

IMPORTANT MECHANICAL INFORMATION: The YZ 250 is sold running very rich for jetting, (I have the 2019 model and made it a great bike). That takes a log time to heat up the coolant, and the engine may not even reach a great operating temperature. I would bet 80% of YZ owners who have not cleaned up their stock jetting, (Mine was so rich, oil droplets from the stinger/silencer ruined the backs of 3 of my jerseys.), have piston scuffing damage. What happens is, the crown of the piston gets hot and expands, but the cold coolant won't let the cylinder expand also, and you get a 4-point scuff with a lot of pressure on the exhaust port, and widen the ring grooves on the piston there because the piston material is bending. I want to feel good heat, through my riding gloves, at the top of the radiators before I take off. I bought my bike slightly used with less than 5 hours on it, from a mechanic at his Dad's shop, and he took off too early, damaging the piston. Get that jetting clean, and smoke almost disappears, exhaust power valves and head/piston stay much cleaner from carbon build up, you get the most power, and the water heats up much faster to good operating temps so you don'y do the mechanical damage that I know a lot of YZ owners have had happen. Thank you, and you're welcome. :) Doug in Michigan

[@Haze-derr]

I have a husqvarna cr 2001 250cc there is no jetting recommendations on the side bought a new carb keihin pwk 38mm Carburettor the shop said it was ready to ride but it just bogs out when trying to give throttle

[@kylephillips1695]

I’ve got a 2017 ktm 300xc went back to the mikuni carb and a jd jetting kit and the new oring kit for the float needle and the metering block I guess it would be called from jd jetting. The jetting is the best it’s ever been compared to a lectron older gen I tried on it for a while and also compared to the keihin with jd jetting kit. But.. I’m still having the slightest detonation after a wide open spot funneling back into the woods and closing the thottle all the way I can get it to go away if I go in far with the air screw but then it’s not responsive like when it’s just a little further out. Should I go even richer with the pilot or a clip richer on the needle ? I’m actually using the stock pilot when the jd kit calls for a leaner pilot and it’s acting the better than what jd kit was calling for. Still that slight detonation so should I go even richer on the pilot or just live with it a little richer than wanted on the needle ? The whole range of throttle is great now the way it is it’s just when totally closed throttle it has the detonation sound or is that a ktm thing ? My last bike was an old 2007 200 xc and the jd jet kit had it running perfectly idk if the newer bikes are like this or what ? Any thoughts anyone?

[@dirtbiketv1]

email jay directly for tech questions-- go to his site www.dirtbiketv1.com to see contact-

[@sendit6011]

Triple triple, I get a bog right in between them. Perfect everywhere else. Something getting stuck?

[@EarthSurferUSA]

Just jump all 6. A stuck throttle may help if you shift up. :)

[@MXguy495]

Anybody have any tips for getting rid of that initial bog right off the bottom of a 250 2 smoker?

[@elcincero321]

Find out your air screw turnouts, reset it and go by feel

[@wayno23]

Try lowering the needle..leaner.

[@xXRedEyedStrangerXx]

Bog right off bottom when you whack the throttle open is likely lean pilot circuit, play with the air screw. Probably need to turn it in some

[@Natedoc808]

adjust the air screw a touch richer until it cleans up

[@legenderekonwheels]

They aren't Philip's head screws, they are JIS

[@jasonjavelin]

Very under rated comment! JIS screwdrivers are cheap and a must have from messing up those carb screws.

[@Pedrofs001]

killer 🎉🎉🎉🎉

[@patrickmuller5223]

Only think i learend where that theres diferent slides not even knowing what the diference

[@EarthSurferUSA]

Still too rich. Smoking a lot. I am not a fan of power jets. All I see is complexity, over richness and I don't think they add any performance when a carb is jetted well.

[@pgbpro20]

I dropped my PJ wayyy down (I think it was 60 to 40) per some forum recommendations. Holy crap - what a difference! My yz is a little lugger now