Keihin PWM Problems, Tips, and Tricks 

Exactly what I needed! You fixed a problem I didn’t know I had with the full throttle issue haha. Came here for idle issues left with full throttle! Nice

I helped the development with the PWM. In karting, in the early 1990's the "top" carb was the Del orto 39 JM racing was selling for a small fortune. But, they didn't show you their set up as it was a very complicated carb. Keihn was pushing their PWK for Karting. The fuel on the PWK dropped out of atomization too quickly when you got off the throttle and it took too long to get back to atomization when you got on. The PWM was close to being a flat slide, but retained the radius on the front of the slide allowing the fuel to "cone" into the crankcase and keep the fuel in an atomized state more adequately. The radius on the back side of the slide allowed the main circuit to be closer to the piston then the PWK. That was the basis of the first PWM carburetor. Our GP 125cc roadracing team was a close to the Keihin USA so they showed up one day to check out the shop. They discovered I had been EDMing their 36mm carbs to an oval"ish" shape and patching up the holes where the EDM burnt through! We had set the 125cc A Gas and B Gas land speed records with one of those carbs! And after showing their tech why it worked on my Flow Bench...well, that's how our short collaboration began. In the late nineties I went back to school and finished my physics degree. I miss the 125cc scene. It was fun testing all of the modifications. I have heard there are no more modifying 125 CR engines. That is sad to hear. The Honda was a bulletproof platform. There is a lot of horsepower begging to come out of that engine.

Hi Jason, Thanks for the tips. Great stuff! I have a 1983 Honda Express Business Moped. Keihin Carb gave me endless trouble.Yoyr tips helped me adjust my old carb just great:) Phillip Bela Bela South Africa

A lot of great info for the inexperienced mechanic. I'm learning as I go. I just cleaned the carburetor yesterday, and the first tip, very helpful. Perfect straight forward video.

Thank you!!!!! I could not figure out why my new PWK carb was sticking. I didn’t line up the notch on the spring. Saved me a trip to the shop.

Great video bro been working on a 36mm pwk just got it back in a 22 beta rr (pain in arse to get out) then watched your video, thought no way going to have to take it off again which would’ve been a major pain in arse but listened for that metal on metal at the top and thank god it made the right sound😅, never even noticed that notch too worried about getting the float level right as it was pissing out fuel before, plus the oil injected thingy majig put back right,😅 but yeah keep making content, straight to point no messing keep it up my American brother 🇬🇧🇺🇸 Jamie

Noticed this today. Great video

Great video! Helped me out a lot. Getting wide open throttle now.

Awesome Video! That helped me alot , especially the Choke Rubber Grommet Tip because i assume that i have this exact Problem and wondered why it was weird to Setup ! And i also had a Weird Problem that the Choke Moves itself DOWN out of the UP Position when the Engine gets Warm - and then Shutting off... I then adjusted the Fuel / Air and Idle Screw a bit and it seemed to Work but i now have Bog if i Full Throttle Quickly , and if i dont Quick Full Throttle it run's Great (it's a Derbi Senda Polini Sport 80cc and 24mm PWK / 6 Leaf Polini Carbon Membrane)

thank you so much I have same carburator im find the problem now is the choke

thanks for valuable info. good job!

Thank you so much for this video. I spent hours trying to troubleshoot my YZ250 carb because it wouldn't idle.In the end I had to turn to youtube. It turned out to be the little rubber boot had slid up. After sliding it back down, the bike would idle correctly and the idle adjustment screw worked as it should.

Thanks for the advanced tips :)

Thanks for sharing very helpful

Excellent video thank you

Great content!!

Excellent video. I have an issue with fuel leaking from the overflow. Is there an o ring around the needle valve seat on these carbs? The brass seat doesn't look like it comes off. Regards Matt

Very Nice videos, Do you have any chart or table to select the best (or lest worst) the jetting of the carb in swedetech engine?? Another question. Why when i tune (jetting) the carb, then, i fire up the kart in the "sicssor bench" everything sounds perfect and work well, then, i get in the kart and kart has so much trouble to fire up. thank you!!!

Ok here's my problem were do you adjust the idle on the carburetor? Like you think it should be in the same spot like every other carburetor

How to set a carburettor to the cross? I have Yz 250. The candle is black. I do not understand what is happening with clicks

Can you make a vid of how to instal this carb

I have a keihin PA MOA on a 1980 Indian moped and when i apply the rear brake it dies if i dont apply the brake it idles ok. What could be the problem? Anyone know? Thank you

Hi friend.can you give me advise?can i use keihini 42mm single for yamaha virago vx535?

Good information

great video thanks

Sorry for my silly question, but I am confused a little. I have an old timer boxer engined motorcycle with two Keihin PWK 28 carbs on it. Obviously there is an idle screw and an air/fuel mixture screw on it. The question is: With the air/fuel mixture screw turning it in and out...so turning it in is getting richer and turning it out is getting leaner? Is this correct? Thanks for the answer, and forgive my english Greatings from Hungary Attila

Very good content and helpful.

@SwedetechRacingEngines Great information! I have a PWM 38 that keeps leaking from the overflow, any thoughts? I haven't even pulled the bowl off yet to look.

I have an 06 cr125 and it has a temperamental idle. I have the adjuster turned waaaay out, sometimes it idles great other times it hangs and can make for some sketchy moments

Thank you..

cart racing so much different than enduro bikes..my bikes throttle cable has to have a extreme radius into carb..no room!..and WOT not really used as often in trail riding at low speeds..but great info on carbs! obviously youve spent alot of time tinkering with theses bad boys!

I have a 28mm Kelhin PWM carb, and it is mounted close to vertical? Is that a problem, because my engine placement is so narrow so that is the only way it'll fit.

Ty

ลูกล่ะกี่บาทครับ

From when they put caffeine in whisky? :)

Hello i have exactly same carburetor. and i don't understand how you adjust idle on these.

What about if you can't find the idle, but the engine starts every time when you crack the throttle?? I have my idle screw all the way in, and still can't get it to idle.... 2 screws on a/f tried different pilot jets, but I think I'm still rich??

thanks

Does this PWM the possibility to connect the oil mixing tube?

Hi friend, I have a yz 250 99, and it has the carburetor pwm38, could you take me some doubts of regulation? it is consuming a lot of fuel, not slow idle, which gicles do you recommend I use?

hi ive been looking in the internet where i can buy this authentic keihin but most of the time i see fake one, so i wounder if i can some tips from here.

Good carb

hi !! why is better the pwm than the pwk... ?? pwm is better for hi rpms and pwk is better for mid range??

Hi , is the pwm float bowl same as a pwk ?

Potresti fare un video dove spieghi il funzionamento del galleggiante?

Hi I have the pwm 38 on my yz how do you set them so the motor will idle. Any advice would be much appreciated

Whats the different between pwk n pwm??any major.different?

That is some great advice. I have a huge channel on youtube and did not know these tips and tricks. Thank you very much and Respect. RH DIOSPEEDDEMON

Is this original keihin or china keihin?

Yes I would lay off the caffeine a little bit.

I hate this carb on my YZ250. Just won't idle.

Boss can you give me carburator

Too much caffeine 🤣

My slide has a bit of play and makes a click noise if i press on it or open throttle a tiny bit. Is this normal? Heres a video of the issue. m.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-MPImlaggGZE.html

4 minutes to talk about two little details on a carburetor. The other 6 minutes and 36 seconds were spent mumbling about caffeinated shaking hands, camera focus, and shit that doesn't matter. Cut out the BS and your videos will have more views. But hey, I guess Swedetech doesn't make its money from RU-vid. It makes it from it's expensive parts. P.S. I love my fuel system for my cr125. It works wonders and has never flooded. Oh, my flywheel cover is sick too.