JD jetting and O ring mod for Yamaha WR450f - Keihin FCR carburetor jetting

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JD Jetting kit:
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In this video I show how to jet your WR450f carburetor using JD jetting kit. We will also do o-ring mod on accelerator pump to get you better throttle response. Keihin FCR carburetors are very popular on 4 stroke dirt bikes, you can follow same procedure while tuning this carburetor.
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wr450f carburetor tuning
JD jetting kit WR450f

[@dgtlionbarger]

Thank you for this! This was very helpful, not so much watching what you were doing but your explanation of it all.

[@dirtniron]

cool, I am glad it helps! thanks for sharing

[@v.i.pblack1132]

Your instructions are easy to understand and your videos are clear 👌 keep it man

[@dirtniron]

Glad you find them helpful, thanks!

[@akathecanadian]

These simple tutorials without no BS before during after, amazing. Also I’m running a 48 168

[@dirtniron]

Thanks Joshua! :)

[@KarlKillers]

I enjoy your 'to the point' and no Bullshit videos, thanks!

[@dirtniron]

thanks Karl, glad you like it ;)

[@BrandonEph]

I have a 2005 YZ450F and it ran like crap when I laid on the throttle, I added this same kit along with the large O ring which my bike had NO O ring, and now it runs KILLER. I’m by no means a mechanic and this was easy. I had a harder time removing my carb and dealing with its hose clamps than I did installing this kit. Followed the elevation and temperature recommendations and I couldn’t be any more happy with the results. Thanks!!

[@dirtniron]

Thanks for sharing Brandon, glad you are happy with it!

[@64maxpower]

My WR was a monster. Just 60lbs too heavy. The yz cam helped a ton too

[@NirHason]

Great video Rado! Well explained

[@dirtniron]

thanks Nir! appreciate the feedback

[@ernesto_yz125x]

Brother best video i have watch on this i am new in dirtbikes and have to clean my carburetor on my 04 crf 250r for the first time thank you for your information its very helpful

[@dirtniron]

Glad it helped

[@jordantamakarov563]

I enjoy watching your videos dude 😀

[@dirtniron]

thanks Jordan ;)

[@MotoMarvmtb]

Excellent video, thank you Rado!

[@dirtniron]

cool, glad it helps!

[@ridelife2402]

This has been a great vide very very helpful

[@dirtniron]

Thanks, glad it helps!

[@geoffpote8109]

Great camera work while working on carb, good video overall 👍

[@dirtniron]

Glad you enjoyed it, thanks Geoff

[@mxrider2strokebraaap54]

Great video!

[@dirtniron]

thanks bro!

[@robertwoods2505]

Thank you Rado!!

[@dirtniron]

My pleasure!

[@m1l6bushmaster31]

Great info,,,thanks

[@dirtniron]

Glad it helps

[@ottovp]

ty great video!

[@dirtniron]

cool, glad it helps!

[@joshsevens9611]

I just looked at this jetting kit it is exactly the same as a YZ jet kit you could save a lot of money by buying the OEM jetting for a YZ and then tuning your carb from that jetting and needle jet after the grey wire mod. There isn't any need for the oring mod either you can do the same thing by tuning your fuel mixture screw and needle position and widening your accelerater pump jet.

[@m1l6bushmaster31]

Sounds like the rpms drop low and then pick up again to idle speed...maybe slightly rich..cant really tell till the engine warms

[@Abitnutts]

Hey mate love your mod vids, a little different here in Australia but a great basis for basic mods. I would love to buy a shirt for my son and I but I am spending all my money on my bike and saving up for one of, the only 400 being built, Aussie Edition 2021 Yamaha WR450F If you are interested in a video on this bike when it is released, and once I have one in my shed, I would be happy to work with you on a video. Keep up the good work champ as I share your passion for the mighty Yamaha 4 strokes.

[@dirtniron]

sure Alix, let me know once you have it. you can email me [e-mail]

[@pillcosbyandtheroofies5140]

Just a heads up that wasn't your accelerator pump, but great video 👍 👌 👏

[@Felixx616]

Hi. I really enjoy watching your Videos on the wr450. But after all these mods you did to your bike: wouldnt it make more sense to go for the setup recommended for the yz or is the jetting kit made for the wr with these free mods done to it. Im not trying to criticize you Im just curious:)

[@makoa2104]

Do they provide the different jets and needles all in one kit?

[@divergent2619]

Since the o ring is really a short term fix before it stretch's, cracks and breaks. Have you looked into r&d power spring or KTM powerparts sxs so spring for a permanent fix? Along with the JD jet kit, ap spring boyesen quick shot 2 or 3 would be total package

[@dirtniron]

sounds good, thanks for the tip. I sold the bike last year..

[@sirkwisbe]

Does the O ring ever fall out? Looked like it was sort of held on sort of not.

[@dominicpadilla184]

Do you have to reject the WR 450 after you do the gray wire and full throttle Mod or is it fine without it?

[@SnipingWithSkillz]

Great video does it not say anything about temperature of weather? Suprised they did not mention pilot 48 anywhere, everyone had good reviews with 48

[@dirtniron]

they actually say that if it is too hot its better to switch to red needle.. blue is rich and red is lean I think 45 pilot works great with JD needles, it is probably too small for GYTR or stock needle, but I am also curious how would it run on 48 pilot, I might switch it and see how it works. I had stock needle and 50 pilot before and it was pretty good.

[@hillbilly3430]

You have great videos!! and they are very helpful tips because I bought my first 4 stroke enduro KTM 400 EXC -F -2006 and they use same carburetor in that model. can I ask where do you live? do you have winter over there?? I,m from Finland.

[@dirtniron]

thanks bro, I live in California so we dont really have real winter here, we ride 12 months over here.. good luck with your ktm!

[@nicksedgwick5189]

After the first jetting did you have to change / adjust anything after running it ? O

[@brandongeorge6388]

Does this mod help with the shutting off when opening the throttle?

[@vitality555]

ahhhh that brraaaaaap sound in the beggining

[@fathersun6238]

Well mine is 450cc / 05 of December,the model .& the problem here is the rpm goes 2 slow after I open the throttle & it stops higher than the normal ofcourse its different when the bike is cold & different if it runs for 5'/10' maximum. But even if i don't ride the bike for a couple of weeks maybe more, it starts with air choke & a little bit up the rpm scroll (sorry for my English)jail lessons. I hope you understand & have an idea how to do it like yours cuz I think we have same model 1year up 1year down 😉cheers 🍻

[@mirkowe2507]

Hey Rado, will i get this jetting in Germany or europe too? Need one for my kx250f from 2008. Thanks Mirko

[@kcdc1796]

What exhaust is that you have on there? Looks sick. Looks kinda like the WB e2

[@dirtniron]

not sure the brand, sold the bike already.. it was cool exhaust and the brand I havent seen before

[@MartinJoelsson-sg9rm]

Reading that drawing, it looks like you are putting it third from "top"

[@Thornicide]

I just put in the JD jet kit on my WR450f but now my throttle gets stuck quite often, anyone know what I could have done wrong?

[@candonic9228]

I recently bought a 04 wr450f and the previous owner had 48 pilot and a 162 main, I noticed it was lean (I’m at 2000ft btw) so I got this kit and changed it to 170 main, 45 pilot and blue needle on the 3rd position, now my bike seems to run even leaner and hotter. If you could help me out I’d really appreciate it, thanks in advance.

[@dirtniron]

You put smaller pilot so the bike is leaner of the idle and first half of the throttle. First try to keep same jets but go with rich needle, then try to adjust your fuel screw. I have fuel screw video on my channel, i had identical bike. It ran great with that combo. Try it and let me know.

[@candonic9228]

Dirt N Iron thank you, it runs good now👍

[@KyleLedward92]

I have a 2009 Yamaha 450F, would the kit you used work for my bike as well? I’m trying to Figure out why my bike falls on its face when I try accelerate fast

[@dirtniron]

sounds like its too lean, yes JD has the kit for all kinds of bikes

[@omarmorales4769]

Hello, my acelerador pump, makes a little squirt, I have adjusted and still go the same, i just checked the diaphragm and it seens good, what else can be? Thanks

[@dirtniron]

thats ok, I am pretty sure it should do that

[@bencowman1048]

I have the same bike and I’m from ohio and this was me at fault I put a 150 jet in it and it barely runs should i j to standard 165 or should I go higher I’m having trouble with tuning these carbs

[@dirtniron]

Ben, I see you ordered JD kit and thats probably the easiest route to get your bike dialed. Follow the chart based on your elevation and you should be rippin. You might need adjust fuel screw or play with the needle a bit. Kit should ship tomorrow, have fun Ben and thanks for the order!

[@louismorris7946]

I have i 2009 wr450 running lean.how hard is it to remove carburator an put back on.how much time should it take.?

[@dirtniron]

I think on those models you need to remove the shock as well. I had steel frame and it wasnt that bad

[@adamwaller9593]

I need some help! I'm confused why this JD jetting kit only has a couple jets do the other jets inside the carb not need to be changed?!?! PLEASE HELP!!!!!

[@dirtniron]

yes, only change the one that come in the kit, needle is very important too

[@scottbellisle5581]

Hey Bud, That was very informative. I bought that aftermarket carb for my 09 RMZ250 and my throttle cables are different than yours. The lower cable fits in and works, but the upper one has that exact same thread on the upper cable. What year is your bike? I will try to order that cable. I ordered one before and they sent me the one I already had. But yours will fit my carb. Any way to see a photo of your upper cable wit the cover off. This way you don’t have to take the carb off, just the cover. Thanks and would really appreciate your help. I’m not having any luck trying to find the fragile one. But not gonna pay $800-$900 for one from Suzuki.

[@dirtniron]

this is from 2004 Yamaha WR450. I dont have the bike anymore. Hope that helps, good luck!

[@TheAngo101]

Just wondering if I was to jet my bike myself, without the JD kit, and after completing the free mods, shouldn't I require a bigger main jet, so the bike doesn't run lean? I have seen a lot of people running a smaller main?

[@dirtniron]

Jd has custom needle that changes the fueling, but once you are wide open its on main jet only. You can jet it yourself, i think go bigger on pilot for sure, not sure about main. Try it

[@edgarmora3201]

Hi Rado, thank you for this video. Question for you. Do you know if I should be able to kick start my 05 WR450 without a starter relay or battery in the bike? I recently put an AllBalls carb kit (stock settings) on and realized after, that my starter relay went bad. So I took out the relay and batterm and I am trying to kick start my bike but don't seem to have spark.

[@dirtniron]

I am not sure, get new relay and connect the battery too.

[@edgarmora3201]

@@dirtniron thx

[@rjongewaard]

I'm here because of your last video on the grey wire mod. If you changed your ignition mapping from a WR to a YZ, wouldn't you also want to follow the jetting instructions for a YZ instead of a WR? I'm having some issues with my 07 WR just curious if I jetted my carb properly assuming it was fully converted to YZ mapping/etc. Thanks!

[@dirtniron]

See how it works, but I think wr will be good. You still have different cams

[@rjongewaard]

Thanks for the reply! OK that makes sense, I thought I must be missing something. @@dirtniron

[@ernestopica7668]

Hey man! i'm from Argentina.. i've got a wr 450 f 2011 i bought it about a month ago.. when i make a quick acceleration from relenti position it turns off... could you know whit precision what's the problem? thanks, i hope your answer

[@dirtniron]

if I am not mistaken you got last year carburetor bike, I am quite sure the bike is too lean on the pilot circuit, which means its lean from idle to mainly. I would first try to adjust fuel screw, follow my video on how to adjust it, hope you have aftermarket fuel screw already, if not I highly suggest to get one. check my other wr450 videos, I show how to install the fuel screw and how to tune your carburetor. If you still cant make it better then you need to get bigger pilot jet. That would be my advice for now.. good luck!

[@sirkwisbe]

Would this work with my 2016 WR450F?

[@dirtniron]

No, it won’t work. Your bike does not have carburetor. It is fuel injected.

[@omariepanton2102]

Can this kit goes on a yz400f

[@dirtniron]

check JD jetting website

[@kylebrackett2543]

so the JD jet kit can make the bike sound different?

[@dirtniron]

correctly jetted bike sounds little different.. its not big difference, but it does sound crisp and healthy

[@angeloskaz]

Nice videos man. I have a 2004 wr450f, it's reeeally hard to start it after one or two weeks with no use . When I make it start it , it has back fires when deceleration , it keeps the rpm hight after deceleration . And if I leave the gas valve open , it over flows . I took apart the carb , and I find out that the main jet is 185 instead of 165 ( the standard one ) and also the jet ( the one at the back side of the carb ) is also too big . I'm gonna change these two jets , and see how it goes . Any other ideas that it might help ?

[@dirtniron]

rebuild the carb, get also new vacuum plate rubber gasket

[@sunmountainhouse8309]

Other ideas: it will always want fresh fuel. Drain the carb after 1-2 weeks. Possibly adding fresh into the tank also to refill carb. I have the same year you have wr450 with the JD kit and jetting. The bike always wants fresh fuel or has your same starting issue. Simple

[@reybabar79]

Why my YZ450F turn the engine off when I throttle??

[@dirtniron]

i dont know man, there could be many reasons

[@bungalawang203]

Can I use this method on Drz400sm?

[@dirtniron]

I think so

[@wrenchone5003]

Sounds purr fect

[@dirtniron]

thanks ;)

[@eugendanciu9789]

Yamaha float adjustament for yamaha wr 450 f 2005? cm???

[@dirtniron]

I am not sure the number, but make sure its parallel with the carburetor.. there are good vids about it.. I have one too.. do the search

[@craigmiller6879]

Love your bent clutch and brake levers. Have you ever heard of hand guards?

[@dirtniron]

What is that?

[@youngczar88]

Is it the same on a 2002 yz426f carb?

[@dirtniron]

i think so.. keihin FCR?

[@4strokecrazydale595]

Does the jd jetting make it more torkey

[@dirtniron]

yes, its more responsive, feels more powerful for sure

[@blackf2276]

Exist this kit for WR250?

[@dirtniron]

yes it does, check JD jetting website

[@SnipingWithSkillz]

Since we both have the same bike what are the performance rebuilding mod we can do? Like cylinder/piston wiseco/stock? Stock crank? What should be done to valves and seals, should it be machined? Keep in mind we want a healthy bike that will last long time. Thinking stock compression ratio just for relaiblity bike is already fast. Video: what are the must do's when rebuilding wr450

[@dirtniron]

I am convinced that it is sufficient to have stock bike and do the free mods, aftermarket pipe and good jetting makes a great difference. Now I have a lot of power, I like how linear it is, it builds up nicely all the way to high rpm. very controllable power. If I would want to increase it even more, I would install new cams. thanks for suggestion Silvester!

[@SnipingWithSkillz]

No i think the power is fine, im just asking when i rebuild my bike what is best for relaiblity, full stock or aftermarket engine parts are better and last longer

[@chrisboehner5255]

Hey Rado I have 09 wr450 and installed the jd jet kit and I’m still to lean probably cause I have full fmf exhaust my pipe was glowing red and popping when I rev it I’m at 2000ft do you think I should switch to blue needle to get it richer?

[@dirtniron]

Get is one step richer whatever jd recommended, if blue needle then yes. And after that set your fuel screw as well, i have a video about it.

[@chrisboehner5255]

@@dirtniron thanks man much appreciated

[@xllitee]

do u know the stock jetting for the 2003 model? im having some issues with mine and i cant get it right and i have no ideawhat the stock jetting should be.. i ride at sea level with a temp around 15 to 25 degrees celsius

[@dirtniron]

you can find it on rockymountainatvmc just enter your bike and the values should come out

[@xllitee]

@@dirtniron you just became my favorite dirtbike youtuber! thx alot man! (Y)

[@dirtniron]

cool bro ;)

[@xllitee]

@@dirtniron but just so you and all others know.. those readings are only for the us bikes. i found that the us bikes and eu bikes are delivered with different jettings. i found that my (EU) bike was delivered with 160 main jet and 48 pilot while the us model is delivered with 150 main and 45 pilot. dont know why they did it like this... but now u know :D take care man!

[@justicebdone7]

@@xllitee difference in jettingbis likely the different emission standards

[@nicksedgwick5189]

Did you do the jetting kit after you opened the air box up?

[@dirtniron]

yes I did JD jetting

[@nicksedgwick5189]

@@dirtniron did you have to change the jetting at all from what was recommended I the jd jetting guide?

[@nicksedgwick5189]

?

[@411BLMPRO]

Hey, thanks for this tutorial. Could you please have a look to my video and tell me what you think about my carburation? Bike is throwing blue flames and I m not sure if it s running too rich or OK.The spark arrestor is removed. You can hear the valves cracking each time you open the throttle.. Thanks

[@dirtniron]

If it backfires on deceleration it is caused by lean mixture. Try to play with fuel screw, give her more fuel on pilot circuit. Maybe try one size bigger pilot. Or lift the needle one notch higher to get more fuel

[@danjim7056]

Jason looks like you, even has the same color walls.

[@dirtniron]

who is Jason ?

[@danjim7056]

@@dirtniron the dude who sent in the picture, you showed it in your video.

[@dirtniron]

Haha, i see

[@maxdecebel]

Какой набор жиклеров и иглу мне поставить на свой wr250f? Живу в Москве

[@dirtniron]

I am not sure about 250, try to Google it, a lot of guys share their setting on the forums

[@robertwoods2505]

Great job! I need a link to that sweet ass t-shirt

[@dirtniron]

thanks Robert! i have some shirts on www.dirtniron.com

[@robertwoods2505]

@@dirtniron Thanks man. Next pay day!

[@robertwoods2505]

@@dirtniron Screw waiting on my next paycheck. I pulled the trigger on the key chain and t-shirt. Thanks brother!!

[@dirtniron]

@@robertwoods2505 thanks brother, appreciate it!

[@robertwoods2505]

@@dirtniron My pleasure.

[@bransonbolt3380]

Could you send me the link for the o ring

[@dirtniron]

O ring is included in JD kit, here is the link www.dirtniron.com/product-page/jdy001-yamaha-yz426-450f-00-05-wr400-426-450f-00-06

[@chevotaman350]

#78 o-ring from hardware store works also. o-rings will break down over time and need to be replaced.

[@jasondobie6739]

Yay Im famous haha.

[@dirtniron]

;)

[@Dramadelta]

I'll be honest with all you guys.I was doing those small modifications at 2strokes RM125cc back at 96' with 96' model race times&it was big difference to all my bikes.Even to my first one YZ 250cc87' when I was 14years old;)Then at 18 motocross time RM (92/96/99),CR (94/95/99)& all the other YZs most of the time.But at those heavy stones YZF250/450&WRF450 Nah....there's a verysmall difference almost zero.Don't give money.Put 1 good exhaust & that's all.Change air filter/oil filter/oils&take the stone(cuz 2heavy)to the mountain.Hello&Goodbye;)

[@anthonynicholich9654]

All cheap after market junk. Yamaha made in Japan parts are expensive for a reason. Why's your clutch lever bent?

[@abelvelazco5450]

I better not see any performance parts on your bike because those are “ cheap aftermarket junk “

[@dougbubba3902]

you have all been had with that o ring mod, 80% fuel pressure increase.. laughable! adjustable by thickness of oring seriously! what about the negative effects of that mod? Keihin are very clever, there is a reason Keihin built it that way and did not put a oring on it.