Honda CRF450R Jetting And Fuel Delivery Explained
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- เผยแพร่เมื่อ 16 ก.ค. 2024
- A summation of a few months of research I did to get my 450r properly jetted. Found many videos on TH-cam that either weren't well put together, or fragmented. I hope that this video can help someone in the same situation that I was in.
- ยานยนต์และพาหนะ
best carb video on TH-cam 👍
Exactly! I learned some crucial stuff from this vid. Thanks Neal, great explanation!
@@hansottosmotos Thank you both!
@@EmersonRaceworks Just awesome.. On my '05 WR450 runs awesome but lots of popping on Decel, 170 main 48 pilot 2 turns out on aircscrew. Nothings clogged should I try 50 pilot 175 main?. 2000ft elevation.👍
You know what man, 5 years ago I custom built a big 650 single with an FCR from scratch with no baseline for jets. Took me weeks and a lot of angry neighbours! I then shortly after got squashed by a kid in a new car and the bike has sat in the garage since. Well iv decided to look at fixing and completely forgotten the jetting orders, in fact was even scared pulling the carb apart. This vid has instantly refreshed my memory, no bullshit, no unnecessary chit chat, straight to the point with all details covered. For what's it's worth here's one random guy on the Internet who is extremely grateful for your time. Now to see if the beast still has a heartbeat... And annoy the neighbours some. Hopefully.
Thanks for taking the time to put this together. I've been trying to fix a 10% throttle hiccup on my 525SMR and this is the first mention I've seen of emulsion tube and/or metering rod wear.
This video sets the standard for knowledge level for pumper (FCR) carbs. Bravo. 👏
Thanks mang! 🍻
Emerson Raceworks where did you get the air/fuel mixture gauge mine is 2004 crf450r pinched to hot cam 490
this has got to be the best, most in depth FCR explanation I have seen. I need to tune my carb on my KTM and this is perfect info
The biggest thing I learned from this is I need an AFR gauge. Of the dozens of jetting guides I've seen, none mention this very helpful tool. Seems like everything else is guesswork and an art. Thanks for the tips!
Amazing ! Clearly explained ! I was lost about lean conditions at slow work on my 450, almost completely lost between hot and cold start, and thanks to you I discovered I switched hot and cold start valve on my FCR41 !!! That explain and make sense with issues I’m facing.
Really nice video, best one on TH-cam !
Love it. I have 4 CRF250R (2006-2007-2008) and they all need a bit of love in the carb tuning area. Very well done and concise. Thank you!
Thank you Neal. I have had so many people tell me bits and pieces of information about how to tune a mx carb, but no one has ever been able to give me the whole picture. This is very informative and well done. Cheers brother!
Thank you very much, I'm glad I was able to help out quite a few folks. 🍻
I have to agree with all of the comments - incredibly informative video about carburetors and fuel/air flow. I learned more from this video than any other!! THANK YOU for making and sharing it.
This is by far the best video and information in general I have ever come across about FCR carbs and I have done a ton of research in the last few years so kudos to you for making it and whoever gave this a thumbs down must have not been very intelligent and probably couldn't follow it. In order to learn how to do something good you need to have an understanding of how it works first and this is what you showed us in the video and I'm sure it will help me be a better tuner. I have been switching my bike between stock and a big bore kit and also from both of those to a high compression piston and each time I have to make jetting changes. My bike ran perfect with the stock piston but ever since adding the HC piston I'm having a hard time getting it dialed perfectly in. I finally have it almost there but I'm still getting some weird surging idle. I have changed every jet and tried dozens of combinations and also rebuilt the acc pump diaphragm which helped with an off idle bog I was getting when twisting the throttle fast but the weird surge is still there slightly. It gets better if I turn down the idle but then the bike is hard to get started when hot and also stalls occasionally. I also noticed if I tilt the bike on it's side while it's doing it it goes away. And lastly it gets only noticeable when the bike gets real hot so after running for a good amount of time straight. It seems like the very very slightest twist of the idle makes huge changes so it's hard to get it dialed in. Any help would be appreciated? Thanks again for the video!
What kind of fuel are you using? High compression pistons typically need higher octane fuel from my understanding. Also what does your plug look like?
Neil... You Are My HERO!!!!! You just saved me months of research! Thanks Brother!
Great Video!!! Hands down best FCR carb video I've seen yet.
Great video man…super well done!!! I really appreciated your well researched, methodical, and scholarly approach you used with the mechanical drawings while explaining the carburetor circuits and carb tuning theory. Everything you said made 100% sense once you explained everything. This video is a great resource and I’m sure I’ll end up coming back to it a few times as I jet bikes in the future. 🤙
This a fantastic video. Really great explanation and very well filmed. Thank you for taking the time to put out such an awesome video!
Thanks dude!
Great video and visual imaging! Thanks for making it easy to understand. Great Work.
Finally found someone who can explain a carby in a way anyone can understand, thank you.
Awesome video brotha jetting was totally confusing, this cleared up a heck of a lot. Thanks for taking the time to put it together.
EXCELLENT video. Thanks for taking the time to produce it and post.
Oh and special thanks for explaining the leak jet! I had a pretty good idea how the rest works cause I had a shit time trying to figure out why my yz450 was hard to start and then run like crap and overheat so I've spent a bit of time puzzling over that same style carburettor. But the leak jet was still a mystery to me till now. My problem ended up being a leaking hot start plunger.... I hope! I'm still putting it back together, good video 👍
John Richardson
How to understand, that hot start plunger is leaking?
Good job explaining all that, good diagrams, thorough, easy to understand, thumbs up.
Well done. Thank you!!!
To get more views, you might want to tag 250 four strokes and maybe Keihin FCR carburetor. I've been searching for a video like this for months. YOU have delivered. Great stuff.
Thank You, and I did just now update the tags for people to find easier. I appreciate the input.
Dang great rundown. Helping me get more In depth with the carb. Thank you!
One of the best carb videos I have seen yet
Thank you, I appreciate it.
5 year old video and still getting good info from it props for putting together such an informative vid learned a lot
Thank you, I'm glad this video is still helping people.
Very educated look inside the workings of the carb and well explained! Good job on the research and details. Thanks!
Brian, Thanks Man!
Great video for someone who has no clue about these carbs. I like the cutaway diagram showing fuel and air flow, awesome documentation to have!
I'd agree....great explanation on carb operation and jetting effects!
best video on this subject i have ever seen. Thank you.
I am very impress with your recaerch and analysis , well don bro
Thank You!
with the throttle closed you have high manifold vacuum and it does pull a lot of air threw the "air pilot, air screw as you referred". also the jets do have overlap and for a street conversion sometimes the key can be in the overlap and the right needle is very important for cruising. very nice explanation.
Yes, and I couldnot find a 'sizable' or 'adjustable' variety of air pilots for this carb. I think there is one size determined by Honda so it's important that it isn't obstructed or dirty.
amazing job! this is incredibly helpful and well done! thank you for doing this tutorial explanation!
Wow....u are a GOOD TEACHER
Looks like this became an obsession to get the CRF running as perfectly as possible given changing weather and atmospherics and to understand exactly what was going on in the carb at different throttle openings. Very well explained and logical approach, the overlaying of the jets on the scale diagrams added to the clear and thorough presentation as did the photographs of the worn parts.
Excellent educational video, well paced and presented.
Would be interested to see how you mounted the sensor probe?
Once the weather warms up a bit here I'm going to make another video of how I got the AFR gauge mounted. A lot of people have asked for that.
That’d be great to see also if you could provide a link to the AFR gauge you used that would be awesome. I’ve never heard of that device before but it sounds like a great tool to have. 🤙
very informative video. well done.I learned a lot that I was not sure of.
thanx and keep on riding.
amzing video, really well explained and well thought out. thanks
Wow this is extremely informative.... Very well done 👏
cheers mate, thank you so much for great info. YT (world) needs you.. dare to say that much!
Really good video man....thanks for posting!
Awesome video man. helped me troubleshoot the FCR on my YZ250F
Fantastic video. Thanks from Australia
Excellent video it's helped my understanding of these carbs
Seriously great work. Thank you!!!
Thank you, I appreciate it 🍻
How has this not got a million views!
Super well done video..Going to help a lot
Excellent detailed video for fcr carb
nice and full explanatory! congrats..
A+ nicely done! You've save me a lot if time!
Thank you,after watching the video i menaged to tune the carb properly on my Crf 250r,it was easy to cold start it,usually one kick ,but after the engine warms up it was i nightmare..It was running rich..
Great video!!! So much useful info
yea this is great. thanks a lot man! just bought a 06 crf450r and i took a vow to never use a mechanic.
Very educational. I run a mikuni tm40 but most of the proces is the same. I consider mounting an AFR gauge myself to finetune
Great video, good information 👍 thanks for sharing.
Very Very Very GOOD VIDEO !!! Great job , Thanks.
nicely done, explained well!
First Class Explanation!
tres bon travail d'explication avec de bons schema, bravo
Wow, this is such a great instructional video! I was going to ask the same as a few of the other commenters, is there a pdf copy of the tuning order?
I was kind of hoping you would have some other video's of similar nature, I can tell you are a great teacher! 👍
Very good, intelligent video! Thanks.
Huge help. Thank you!
You did an awesome video
this video is the bomb. badass tutorial. I have learned so much about my own fcr carb now.
Im really glad it helped, that was my whole intent. Cheers
Neal Emerson hey u have the part number of the a/f gauge u used
I got it from Innovative Motorsports website www.innovatemotorsports.com/products/mtxl_plus.php
Great video, helped alot
Very, very good video 👍👍
i agree t.. he makes total sense and u can understand
Most detailed FCR video I've seen! Any advice or could you make a video on adjusting the AP timing screw/and leak jet? My ktm 525 bogs a bit off idle and I'm not sure what adjustments to make to help. Cleaned everything and got it spraying/working as it should, just need to fine tune it. 42 pilot, 1-1/8 on air screw as J/D jet kit recommends.
Great job mate
Great video!!!
awesome video!!! i love the detail!!!! popping on decel is a sign of lean pilot circuit..
Popping on decel is sign of the lack of an acv circuit (not needed on racing carbs, only street bikes have it). Kudos to the creator, this is the first time I see someone tuning an FCR (or carb generally) properly.
@@panosvougiou Can the carburetor be somehow tweaked to not induce backfiring even without air cut valve? Spend almost whole day tuning polini pwk30, thinking my pilot jet was too lean, which is not the case evidently.. if I go rich enough, the backfire's almost gone but the bike won't start, cause it's too rich
@@peshhhiify hey, please refer to guides on how to adjust your idle speed/ims screw, it's a relatively easy process. A bit of exhaust popping is expected when your idle mixture is set properly.
@@panosvougiou Thanks! I finally discovered, that the problem was unmetered air passing through bad sealing after the carburetor. That's why a i wasn't able to tune it properly, especially on the pilot circuit, where it got the most pronounced..
Awesome Video. The way you took the time to explain how each circuit works was the best I have seen. I do have a question on the A/F gauge. Where did you place the probe in the exhaust?? Like X distance from the exhaust port??
I welded in the bung for the AFR sensor right near the mudflap area above the swingarm. The instructions for the wideband sensor tell you how far away, and how to orientate the sensor in the exhaust stream.
Great video. Can you please offer up the reference documents you were using? These look very useful.
I have watched so many vids on how to clean or rebuild these FCR carbs, but very few explain (or do so what any degree competence) what each circuit does with interaction, and what to look for to tune, particularly the air/fuel ratio. And the fyi regarding the emulation tube, and what the hot start does... excellent!
I have a few questions:
1- would you post a link to your Tuning Order document?
2- how would elevation affect the air/fuel ratio in terms of target ratios? I'm assuming 12.5 / 13 is still target, just what jets and such it takes to get there would change? (I live at 3k ft and ride between 3k and 9k ft.)
3- what gauge/instrument were you using and how/where did you connect it? I'd love to see a vid on just that :)
Thank you for an amazing & very helpful vid.
such a well informed video on this carb, ive just completed a street legal crf490 build and have been dealing with this nightmare and im bored of having to remove the carb at this point😅
im getting very close but as you say getting the cruise right without hesitation is abit tricky
what were the jets and needle specs you ended up with out of interest?
also going to get myself an afr gauge so theres no doubt left, ive used afr’s on my cars in the best but didnt think the stock crf electrics would power it.. so good to know this is possible
also last thing is could you provide a link to the guide youve made to make the process abit easier when working at the bench
cheers for the help, this is an awesome guide
Um... This video is priceless. FCR guru this guy.
Great vid, thanks!
Very well explained, you should teach a class.👍👍
Got a 02 crf450 going sumo but the carb tune has sent me to bed countless times unhappy but A+ with the video time to get a AF Meter
450r🤓
Great video, super helpful. Show us a video on how to install the air fuel gauge please. Also let me know what model you put on your bike. Everyone will love you for it. I'm assuming you have to weld a thread fitting on to the exhaust pipe to accept the sensor?
Great video
Thank you for this
First off, fantastic video and probably the best explanation of how a carb works on the internet. Second, what are your sprocket sizes? I recently converted my 08 450R to street, and Im curious what works best for you?
I fit a 15 tooth on the front, and a 44 tooth on the back. Stock internal gearing. With this setup its perfect for daily street driving. it can operate at ~65mph no problem without over revving and i've had it up to ~98 tapped out.
Awesome video man! What were the main changes that you had to do to your carb for the sumo conversion? Im assuming mainly the needle?
great video..thanks..
Good video, one of the best I've seen on how a carb works and the air fuel ratio guage was a bonus. I'm looking at purchasing an afr meter to sort out the afr on two of my bikes. I do have a very nice digital carb balancer that has other functions for fine tuning afr etc. but on my v twin its not stable enough to get a steady reading and a colourtune plugh is not fine enough to see the colour change so an afr meter seems to be the way forward?
Great vid.
excellent, you know it well
Love your detailed explanation. Where do you get the gauge setup and how to connect it to the bike?
Wow great video. I've been trying to figure my 07 out. Falls flat when I hit wot fast. If I slowly wind it up it's better.
Great vid. So what would it mean if I have a slight miss fire on the idle AND choke circuit? I waa under the impression that the choke corcuit was its own circuit of air and fuel? When I got this 2006 CRF250R it had a 40 pilot in it has a 172 Main and the needle clip is in the third position from the top. Well I had to go up to a 45 pilot and move the needle clip down to v slot from the top to get it to start and then run smooth at warm up from the idle circuit to the mid-range.
Now when I put it on the choke circuit to start it when it's cold there's a slight Miss and then when it's warm it still has the same Miss on the normal idle circuit. I believe that the previous owner put in all balls jetting kit in it because of the number engraved knob headed pilot fuel screw as well as it had a silver number 40 pilot in it. That kit comes with screws pilot jet needle and the adjustment screw for the pilot fuel screw and for carburetor Bowl screws.
With a 45 pilot when I screw in the fuel screw at idle after warmed up it will start to die off and stall out and a half Turner below out from seated. But I don't really notice a whole lot more after 2 or two and a half turns out. So I'm contemplating I'm going back to the original stock needle as I'm not sure if this all balls needle is quality enough. You can find a video of my issue on this bike on my channel as it was just uploaded the other day. If you've gotten this far thanks for reading and I look forward to your reply. Andrew C
Thanks for your video Neal. Excellent! I want to try a new emulsion tube in my FCR on my KX450F. On the Kawi parts diagram the only part I can find which might be it, is something they name the "Nozzle main". Part 49121. The main jet screws into it. Is that the emulsion tube?
great video . could you show a close up pic of install location of the meter sensor?
Great video! May I ask where exactly you have welded bung for wideband sensor? How close/far from the engine?
Thanks a lot, my supermoto with a fcr is popping on decel quite a bit trying to figure out why
Man, great explanation, how do we get a copy of those documents you put together? Would love to review it for deeper understanding.
neal, excellent video...i've been fiddly with the carb on my 450x for 6 months...can you tell me where you got those awesome FCR diagrams? i found that the little brass 'ball' that apparently seals the top of the hotstart pathway leaks air and dirt into the carb body....
Very nice video. How is the AF sensor installed?
Great video, the fuel flow diagrams are just what I was looking for. I have looked all over for those, where did you get them?
The fuel flow diagrams I got directly from the service manual that comes with the dirtbike from Honda. I just made larger copies of them individually to use for the video, and highlight on. And Thank You.
Einstein said "if somone can not explain complicated things in simple way, its means that he does not understend it" Great work. Can you share how You had instal the AFR meeter with it sensor?
Great video! Thanks. Can you give us links to materials and that air fuel gauge setup?
This is awesome. Some one that explained all the circuits and jets in the carb. I would like to know what fuel ratio gauge you have and where did you get it.
I also would like to know the answer to this question.