pwk Carb Jetting, Setup and Tuning
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- เผยแพร่เมื่อ 29 ก.ย. 2022
- In this video I go over every part of how to tune a Carb while its on the bike.
Starting from the pilot system to the Needle system and finally the Mains.
This video is for 2 and 4 strokes. - ยานยนต์และพาหนะ
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"it's as easy to lose as a 10mm socket" made me laugh pretty hard...
Quick and to the point...easy to understand, no fluff. Thanks
Thanks Matthew much appreciated.
Man thank you so much great video! I've been trying to tune my pwk for my pit bike and no such luck until I found your video thank you brother! Grip it and rip it!!
That's awesome, happy to help and enjoy!
This was a great help. I really like how you mention both 2 and 4 strokes, with that information I've been able to tune my minibike😁
Thanks man awesome to hear it was helpful, Mini bike sounds like fun.
Thanks for posting this, it helped me get my bike dialed in and I am over the moon happy right now sir :) Great video!
Awesome I'm happy it helped, what's your bike?
@@TheMotorcycleForge You may laugh but it's a heavily modified Hawk-250. I love working on these things for some reason and this bike is super cheap to work on and learn. My next project will be to restore something more classic/iconic. Again man, thanks for the help with it, the pace and info in this video is absolutely perfect.
Still a cool bike, I look forward to hearing about your next project.
Thanks man means a lot.
Love your ol dt175 have an 81 xt500 was my first bike I purchased at 18 and I'll never get rid of that gem. Insta sub, excellent explanation, and even better taste in bikes❤
Awesome thanks man! ,xt500 is a great bike
Dam my bike is going so good now. Thanks man
Glad to hear it!
Wow thanks for the video it really helped.
Good video brother.... Quick and to the point
Thanks bro, much appreciated!
By far this is the most realistic on how to tune a idle carb! while the other places explain like it some kind of quantum physic science making it nore complicated then it shouldn't .
Good info bloke!
Good info man thanks 😎
the intro was epic😂😂😂 “if your bike is running like sifhisbdisbejcbkwdn” got me🤣🤣🤣🤣
Hahaha ikr ,its a classic
Great video sir, I have a Honda XL 650 the Orignal carby was shit so i bought a PWK 36mm and it's so much better, I recommend the PWK Carby on any older bike
*good job my friend*
very nice explanation! i didn't know that lean pilot jet can cause a slow rpm return when closing the throttle which i am experiencing right now on my bike. it's a little bit complicated because my carburetor has accelerator pump so i have more things to get working properly
Thanks man much appreciated. The only thing to remember with the accelerator pump is it adds fuel with throttle movement (rolling it on)
but not when holding the throttle at a fixed position like 50% for example.
What is the project bike?
Awesome video Thanks
Thanks, much appreciated!
Hi, i have a 26mm one of these carbs on my YX140 pitbike and its running like a bag of shit. It has a 85 main jet and a 45 pilot jet. Can you help me to get this to run right. I have a 102 jet which i can install but idk if its a good idea or not. Please help
Hello sir, i have an old Honda xl185s and im looking to tune the carb, stock carb/settings but it high speed its stuttering but when i open the throttle fully the it cuts out and then cathes up
If you have a accelerator pump that may be the cause or when cracking the throttle it's getting a big gulp of air and leaning out till the fuel catches up.
Where can I find the "ear screw" ?
hello, nice video! thanks. i recently bought a pwk34 for my bike and i got it running ok i guess but i have a question: what does the screw besides the negative pressure hose do? it doesnt seem ajustable since it doesnt have a spring so unless is tighten it surely come off with vibration. should i keep it tight or unscrew it ? please help! anyways good video i got my mix right thx
im talking about the screw on the top, next to that short hose on the air side of the carb hehe yours has it too
So if you are talking about the screw above the intake trumpet/ air filter side.
It's supposed to be for adjusting the power jet/ it's for two strokes but personally I normally don't use it as it makes tuning the main jet a little more complicated.
@@TheMotorcycleForge i have a 4 stroke so im not even touching it now that i know haha thank you! my carburetor came with 2 spare main jets, one pilot and another needle to set it leaner i guess (the number is smaller on the spares). i have my engine running decent with almost 3 turns out so i have to change some things. should i change the needle and pilot too if i put the smaller main jet? or is it enough with the later. thank you in for your time to reply. i really appreciate it
If you have the pilot circuit working well at low rpm you shouldn't need to change it when you change the main jet. The needle is just for the part throttle/ mid range so I would only change it when alternating needle height doesn't help.
Hi, I'm from Argentina and I bought a fxr 150 but it came with a honda tornado carburetor, a keihin 32mm, I understand that the chicler measurements between keihin and mikuni are different and I don't know of an equivalent, I know that the original fxr is 27.5 idle and 115 main, I would like to know which keihin chicler could go well, by the way, good video
So I run a 30mm keihin pwk copy on my fxr 150s. With around 40 pilot and 112 main jet.
A 32mm carb is probably a bit big for a fxr150 but I haven't tried one so not 100% sure.
Hi, I have Dt 175 and 30mm oko carburetor + vforce4. Do you think the most efficient setting is 150 main and 50 pilots?
Every bike will be slightly different so you will still need to do some testing but that's what I started with in my Dt175 and It went pretty good.
@@TheMotorcycleForge thank you for the answer :)
No problem, if there is anything else just ask.
Cheers Logan
i have a gx390 engine and a pwk 30mm carb on kart, wich sizes you recomend?
I would start with a 115 main and 42 pilot which is a good starting point and see how it goes.
Then after you could try a 112 or 118 main to see if it gets any better. .
Hi mate quick question I have vforce reeds in my bike what jetting would you suggest as running rich
Will need some more details.
What bike is it?
What carb is on it atm
What jetting atm?
What exhaust aswell.
Do know what jets would go into a 420 predator engine with a 34 mm carb , no one has those stats wish you would do one your great Class a gentlemen ty
I haven't jetted a predator engine before but if it's a pwk carb or similar. I think a 145 main and 45 pilot jet should be a good starting point. You could start one size richer to be super safe but this should be pretty close.
I’d start with a 120 main 32 pilot & go from there
Hello from Greece! What size and needle height would you recommend for a stock suzuki fxr engine with open exhaust and keihin pwk 28?
For the needle I recommended these two, N80F or JJY and I would start in the middle grove and see how it goes. May need to lower the needle/lift the C clip depending on bike.
Hope this helps.
@@TheMotorcycleForge Thanks for the quick reply! I wanted to ask about the sizes for main and pilot jet .
Ok jet wise, we run 112 and a 42 in our 30mm pwk's.
For a 28 I would start around 108 main, 40 pilot and see how it goes and adjust from there.
What is a good jet size for a china 150cc Enduro with a big bore kit with 65mm piston, 26 mm flat slide keihn carb and yashumira exhaust. Right now I have a 40 pilot and 110 main, clip in middle on needle. It is a 4 stroke. It back fires on deceleration. I tried a 115 main and worked without connected to filter and airbox. Connected to airbox I have to drop to a 110 main jet . With the big bore kit the 150cc should be somewhere between 180 and 200 cc. I will try to open airbox a little to low for bigger main. I was thinking maybe changing pilot from 40 to 42 or 45 to help get rid of backfire on deceleration. Seems to run ok through out the throttle range, could be a little better I think. No bogging but not great acceleration on top end.
Ok so your on the right path with the backfire, a bit richer on the pilot jet should help or try turning the mixture screw in a 1/4 may also help.
I think a 110 main in a 26mm carb is probably to big. I run a 112 or 115 in 30mm carbs on our 150cc bikes.
Maybe a 105 might give you more acceleration.
Last but not least if your engine is 180cc to 200cc a 26mm carb will probably limit top end power , depending on what your bike revs to and its stroke.
Hope this helps.
@@TheMotorcycleForge when the bike was 150cc before the big bore update I tried the 28mm flat slide and it simply did not work, poor performance. On a Kawasaki kmx 125cc 2 stroke the 28mm worked fine. On the 4 stroke china bike I had no luck, once I tried the flat slide 26mm it worked, and jetted easily except for the deceleration backfire. I'm a little worried about going to a 105 main it might be to lean. It ran good with no filter on top end with a 115 main. It runs ok on top end but not as good as the 115 without filter. Don't want to run bike with no filter to much rain and dirt here. We will try to open air box tomorrow and see if that allows for a 115 main. I will bring a 105 main if the 115 does not work. I tried adjusting fuel/air mixture screw but did not get rid of backfire.motorcycle is heavy. I have a rack on the back to carry a top box and 2 water containers 20 liters each, around 5 gallon. It's my typhoon, shtf bike. My other bike is a Yamaha aerox with the 155cc engine. Great bike but a scooter and is boring as hell. My girlfriend won't ride on china bike. She's scared of it. Plus it's high off ground like most dirt bikes are.
Sounds like you have everything pretty sorted.
If the airbox mod doesn't work you could try a 108 instead of 105.
Only other thing I would try is a get a air fuel ratio gauge.
Will make tuning simpler as bikes can pop on decel when lean and rich.
@@TheMotorcycleForge thank you for the feed back. I live in the Philippines on an island surrounded by the Pacific ocean. No fast food or malls here. Can order things, takes weeks to get. Maybe we can get maybe 10% of the variety Amazon sells. I have jets from china they are 110-115-120 etc. I order jets for pwk slide carb from different sources and see if I can find something. I prefer adjusting jets up or down at 2mm at a time instead of 5 at a time. Will check spark plug also to see if running rich or lean. I only have 200 km on the big bore kit. I only have about 800 km on bike and when I bought the bike new the place I bought it from said they put 20w-50 full synthetic oil in it. I wanted regular oil for break in and I had to drive around 50 km to go home. Checked oil when I got home and it looked like clear fluid with zero lubricating property's. Changed the oil right away with a good non synthetic 10w-40 oil but the damage was already done. The bike ran ok but it belt like I was driving a horse and buggy, so slow I could not stand it. When changing cylinder the cylinder walls were scared at 500 km. All because what ever oil they put in the bike was useless. I should have had the dealer change the oil with oil I provided. You shift in second and give the motorcycle gas now it will throw you back in the seat. The speed shop that sells the big bore kit rates it at 180 cc. Me and the mechanic both feel it's more in line with a 200 cc. So close to having it running the way I want it. The bike hauls a*s. But could be a little better. Police here have been known to tear the muffler off on after markit exhaust if to loud. I have a db killer baffle installed in muffler which makes it a little less noisey. If I get rid of the back fire I can keep the pipe longer.
Dam that's a pain about the shipping thing, really makes projects take a long time.
Sounds like the bike is a ton of fun to ride, yeah synthetic is pretty crap for running a motor in, the dealer should have known that.
Do you know what the stroke of the bike is?
I have a am6 engine with a big bore kit, exhaust and all that stuf and i had a dellorto 21mm carb on it and it ran fine with it then i got a mikuni 28mm flat slide carb and the problem with it is that when you give it quick full throtle it bogs down. I tried biger main jet, tried different float settings and nothing realy helped. Its got a 32 pilot and 150 main jet. Please help i realy want it to work good again.
I would possibly try altering the idle mixture it may only need 1/4 turn in or out but my guess is that the carb is probably a smidge big for that motor. Does it accelerate smoothly when you roll on the throttle slowly?
@@TheMotorcycleForge when i slowly give it doesn't bog down
Yeah that's the same with our race bikes and the conclusion I came to is because the carb is a bit big for the engine. At low speeds the rapid change in throttle is to much for the engine but it will still gain some power up in the high rpm as a result.
@@TheMotorcycleForge Yeah probably. But i tried adjusting the air screw and its not as bad as it was before thanks a lot!
Hi mate, i just have a question i have an 150 cc bike it's all good everything's working fine but there's this issue when i turn the throttle full the acceleration is dull but when it's 3/4 throttle it accelerates very fast & idk what's wrong the cable or something
Is it 2 or 4 stroke and what carb do you have on it?
@@TheMotorcycleForge it's a 4 stroke 👀 & idk about which carburetor u mean , i just knw the basic one😐
Sorry I meant what size carb is it, also what jet's are in it?
The main jet is too big, should be lowered until it accelerates to full throttle.
So detailing explanation. Greetings from Greece. Thank you for this video and all the useful info, man, but there is something i can't get over. Idle is always too rich on my pwk 28 keihin. I'm running it on an yx 150 ksr type engine. Idle jet is 32 main jet is 108. I don't know what's wrong with these carbs. May there be a problem causing that? I'm talking about the engine flooding with fuel from idle to 1/8 throttle, the rest is perfect. I can't find amy solution anywhere. I hope you could provide some helping tips, brother. Thanks again!
What adjustment is the mixture screw at?
Also there might be a small peice of material causing the float valve to leak or the float might be set a smidge high for perfect seal.
@@TheMotorcycleForge even if i completely remove it, the motor still runs too rich. I took it apart an hour ago, blew some air through all holes and replaced the needle. The idle now is more stable and the first eighth of the throttle is great but now i got another problem and i guess i need to play with the needle position and main jet. It bogs at 1/4 when opening the throttle after cruising at less than 1/4. Bogs a bit and goes along. Screams lean but I'm not sure.
Yeah it's definitely possible it's lean but most Pwk copies I have found are rich at part throttle when the clip is in the middle grove.
Check at choke system
Do you have a link for a jet kit? All the ones I find have the main jet at least a 100 and I know I'll need a smaller size
Unfortunately I don't know of any kits either so when I need a main jet smaller than 100 I order them individually from these guys as they are my nearest stockest. www.motorcyclespareswarehouse.com.au/products/keihin-main-jet-large-hex
@@TheMotorcycleForge thanks I'm ordering several sizes so I can make sure I'll get the right one
Is it bogging when you give it full throttle like a jab and stumbling no power after changing your carb? I got a defective JFG flat slide carb I could only tune idle and that's about it I bought tiny jets like 40 I'll try to find the link
@@calambres6614 it was bogging bad but I started to increase the main jet size and it keeps getting better. I would of never thought it would take such a big jet but it runs great now. At least now when I put the G2 reed valve and pwk carb on my phantom 85 I'll have a lot better idea where to start but I'm waiting for someone to make an expansion chamber for them so I can do it all at once. A good expansion chamber would really open them up and if nobody makes one by next summer then I'll try to find someone who can make me one using the stock exhaust for the flange. I'll pay the person obviously
@@Westhelockpicker expansion chamber sounds interesting
my bike dt 125 newly rebore and i use yamaha rxt 135 piston with ring. also use 4 stroke carb yoshi r 28mm i use 120 main jet and pilot jet 40 run it perfect. but i want to replace it with my stock carb mikuni 24mm the stock jetings is 165 main jet and pilot jet 22.2 the bike not run. what jetings can u recommend. and tnx for the video i got an idea
So does it not run at all or just rough?
Give the stock carb a good clean and make sure no jets or passages in the carb are blocked before changing jets.
@@TheMotorcycleForge with the stock carb mikuni the bike not run. also i clean the carb very well i think the jetings of mikuni has to replace
So jetting from mikuni is difficult to keihin for example. A 100 keihin jet is the same as 200 mikuni jet.
Pilot on the mikuni may be to small nut cant hurt to try some different jets
@@TheMotorcycleForge thank you ♥️
For the pilot going from 50 and 4 .5 or 5 turns out... then going to the 45, how many turns out? And was 45 right or did you drop to 42? 40?
From memory it still has the 45 in it and roughly 3ish turns out, was a while ago though.
@TheMotorcycleForge @TheMotorcycleForge thanks! Used a jetting calculator and can't get exact sizes...
Stock 4th clip down. 160 main, 45 pilot.
Used two calculators. First was to see jetting for aftermarket exhaust, second Used the values from the first. 155 main, 3rd clip down, and 44 pilot....
The reference of your almost 5 turns down to 3 moving from pilot 50 to 45... so stock states 2 turns out on the air screw, to get closer to 44 the calculator came up with.. I'll be aiming for somewhere between 1.5 to 2 turns out.
Sounds like a plan, should go pretty good.
I have a predator 212 motor that's heavily modified with a 28mm pwk carb on my mini bike and it revs out perfectly fine but won't idle need help
Ok so first, have you made sure a nothing is clogging the pilot jet or any part of the idle circuit.
What pilot jet do you have in it?
Will it idle when you turn the choke on?
It has a 38 pilot jet and yes it will run on choke
Then you need a bigger pilot jet, maybe a 42, get her up to operating temp and tune it to suit
@@TheMotorcycleForge ok thanks for the help I really appreciate it
Were do you go to find out what a needle doe's DDJ CELL LGL DEK DGJ thanks.
In a previous carb video I do a diagram and explain more in depth how needle operates.
How can you check if the float os ok or seating too much down ??
I have done a previous carb video and I go over how to set float height correctly.
If it's set to low it will run out of fuel at wide open throttle.
What happens if the pilot is extremely lean
From factory my pilot is 75 and main is 160
I have a jd jetting kit and it’s telling me to put a 50 pilot and 170 main
Generally bike will be slow to return to idle if to lean on pilot jet., may pop a little on decel depending on bike.
I think a 50 would be ok, if you follow the video I give a full list of symptoms and how to tune the carb.
👍
i am still wondering how much turn is considered as 1 turn ??? is it 1/2 turn or 360 degree turn ????
1 full turn is 360 degrees.
From my observations, each carburetor component affects the entire rpm range. Take the example of the main jet - it is said to work 3/4 to full. To check that theory its enough to put a jet half as big as needed - the motorcycle will not even start from 1st gear. Engine will just turn off. And the same that too large - it will flood. No less good work - explains a lot.
Yeah as I said they all overlap haha and that is a extreme example as of course it won't run with a jet 100 sizes out
Interesting observation. The jet needle has the same diameter at the top but it becomes long and tapered. As the carb slide lifts the taper starts to allow fuel to pass. So the idle jet starts it off, then as the slide goes up, even a little in first gear, the idle jet maxes out, fuel is needed to balance the increase in air, so the main kicks in to help. The main is helping but not yet carrying the load of fuel it is capable of. When you think about it, the carburetor is a masterpiece.
I have a Yamaha xtz 125 with 26 nibbi carburetor (105/35 jettings) can u recommend other settings?
I would say that sounds pretty close, how does it run, does the pipe look rich or clean.
@@TheMotorcycleForge its almost perfect,i check the sparkplug and its brown
@@TheMotorcycleForge i will try 32 pilot jet next week if it will run smoothly
So is it running rough on idle, part throttle or wide open?
@@TheMotorcycleForge what size of carb u can recommend for 125cc 4 stroke street legal enduro and also jettings
Okay can someone help me becouse i dont fully understand english so if someone could detect problem for me i would be thankful. I have problem with my carb cuz i have to rich fluel and my spark plug is almost fully black( and burn in about 2 mth) . On the leanest fuel setting it still happens for my spark plug to be fully black. I also wanna mension that my true powerband in my 2 stroke is hard to get.
What carb do you have on it, what bike is it and what jetting is in the carb?
Can i use pwk mains on a pe carb?
Yes they are the same according to Keihin
How do you tune the power jet?
As I understand it the power jet affects only full throttle so I would tune that last and use the same technique as tuning the main jet, I avoid using power jets as there is no real gain on the bikes I use.
Hope this helps
@@TheMotorcycleForge yes, there's not a whole lot out on how to use, or what the proper procedure for setup after everything else is good. I appreciate your time friend. Thank you.
No problem Shaun, goodluck with your jetting.
How does one install throttle cable?
As long as your throttle cable has the correct fitting on the carb end it's pretty easy.
Just compress the spring and locking tab up to the carb top and put the end of the cable in the cutout in the slide and release the spring & locking tab.
*can you tutorial for ECU of motorcycle without DYNO ?*
Yes I will when I get one, most of my bikes are carb'd atm.
I got a 24 pwk can’t get it to idle bike just wants to take off
High idle can be from a few things.
Throttle cable is adjusted to tight.
Something is stopping the slide returning to the bottom, Im guessing you have adjusted idle speed screw already?
Bike could be to lean on idle circuit either from incorrect jetting or you may have an air leak.
Mine runs but idles way to high and the idle screw basically does nothing. I had it run away from me already
First thing to check is that your throttle cable has some free play as it might be holding slide open a bit, Second make sure nothing is obstructing the slide from closing properly, lastly it might be lean on the idle jet so a bigger idle jet may help.
My bike goes bown chica bown bown.... chica bown bown. and turns into "strip clubs" by its self. I've got it tuned perfectly!
Idk why when I start giving more throttle it starts to bog but once I get going it stops
Is this when you open the throttle fast or slowly and what size is the carb compared to stock.
@@TheMotorcycleForge it’s when I slowly open it and it’s a stock carb
What bike is it and is this a new problem or always like that and have you changed anything on the bike recently like exhaust ect?
@@TheMotorcycleForge it’s a new motor it’s a predator 212 ghost
Well I would check the basics first, what is the plug condition like?
Is the sparkplug gap correct.
Set up the carb correctly, float height ect.
Go from there, if still no luck consult who you purchased it off.
I had a nibbi carb spent.3 hours on this and it still screwed when.you.rap the throttle it would just.cut.out.Think i.got.a.defective carb no matter what I tried something going to try a different brand
Sometimes if I carb is to big for the engine it can cause engine to cut out when throttle is opened very fast.
What size carb and bike?
@@TheMotorcycleForge 150cc 26mm carb 4.stroke
Ok cool and what jets do you have in it and the needle position?
@@TheMotorcycleForge 35 pilot and 108 main and 3rd groove up
Ok at a guess 108 might be a bit big for a 26mm carb but if you have tried leaner and richer maybe it is the carb.
I would try a 100 main jet and if its better after that try a 98 main.
My tanung ako Bakit maliit na main jet og pilot jet nalulunot walang power
Using google translate as I don't quite understand what you mean.
Every bike is different so your jetting may be much different than mine.
Hope this helps
I have about three full sets of sockets.... it's always the 10mm that is missing 😂😂😂
Yeah that's sounds about right 😆 sneaky 10mm
Mine isnt running
More info? Carb, bike? Jetting ect
car carbs are a snatch compared to bikes, One hasnt tuned til ones tuned a bike.
Yeah man I couldn't agree with you more
My PWK 24mm at full throttle is like rolling...
What bike and what jetting?
@@TheMotorcycleForge can I send you email ? I would like to show you the spark plug if possible slow 35 and main 115
Yeah my email is on the channel page I think.
Is it a 2 or 4 stroke engine?
@@TheMotorcycleForge 2:stroke 80cc
Looks like is misfire at full rpm is it possible the mix oil in gasoline in the tank is too rich because was okay before with 1 n half turn on adjustment srew, since I did the mixture too rich in oil starts to do this
that carb is seriously angled away from vertical! the float must be set really low.
Yeah It was a bit of a test as I was sceptical. It seems to work as it should, apparently you can run them up to 40 degrees inclined. 🤔
i am impressed! the float chamber cannot have much fuel in it! i couldnt get a pwk to work at an an angle at all!
Please work
?