This should be the #1 video in a search result for anything like "Keihin float level." The instructions in the KTM manual aren't worded well, and this explanation clarifies in a *very* concrete and clear explanation. Well done, thank you! I'm disappointed that this only showed up in recommended videos days after searching for something exactly like this and not finding it the first time. Hopefully the algorithm will get it right for future searches!!
Thank you for posting this video, I was having serious trouble fouling plugs on a used 2 stroke I purchased 8 months ago. The factory KTM manual's explanation of setting the float height was total garbage and caused the bike's pilot jet to function more like a pilot fountain. After watching this video I was able to accurately measure and set the float height which resolved my issue.
absolute best float level adjustment video so far, excellent job explaining everything, especially purposefully making the float stop at the wrong place
Very nicely done video, Mark. It is so hard to explain how to do the float height adjustment with just words. What I've found with the Keihin carbs after measuring it for years, is that the seam on the back side of the float will be nearly flush with the base of the carb body when the floats are at ~7mm's. I adjust it so the seam is just slightly recessed below the carb body and that gives me ~7mm's.
6:55...A simple way of explaining this is to say that the float valve needs to be closed BUT you don't want the spring in the end of the valve compressed at all. :-)
Perfect help. Old gas had gummed up my float valve (completely stuck, open), so a good cleaning and height check was in order; much appreciated. PWM 38mm; very similar.
What I like best about this video is I’ve finally heard someone pronounce Keihin correctly. It’s not Keehin, it’s Kayhin. Whenever I pronounce it right shop people look at me like I’m dyslexic. Little do they know I lived in Japan for many years
Thanks for making such a clear video. I hadn't ridden my TE250 in over a year. it started up very easily, but the carb was leaking a lot when sitting at idle or off with the gas valve open. This is will help me fix the problem!
Pleased that you enjoyed watching the video. It sounds like your float may be stuck, or there is some debris stopping the needle valve closing. Or the needle valve rubber might be damaged and need replacing. It should be easy to figure out what the cause is by taking off the float bowl and checking whether the float moves freely and if the needle valve is OK.
@@TokyoOffroad I have a question, the brass hole that the needle valve seat in there are two small holes on the sides and one in the middle. is there supposed to be a small channel on the sidewall? can the brass needle valve orifice be replaced? I cant get it to stop leaking and i think the orifice is bad
Excellent, thank you so much! I'm having issues with my carbs at the moment and for the life of me can't seem to get them to behave properly, no matter what I do, lol (noob here btw), especially with overflowing fuel when the bowls are fully. This will come in mighty handy, thank you!
If fuel is constantly overflowing then either the most likely causes are that the float valve is stuck, there is some dirt in the float valve, or the valve rubber is damaged and leaking. I recommend taking the carb off the bike, remove the float bowl and inspect the valve for damage, or debris.
So it doesn't matter how much the float tang is pressing on the needles suspension at this setting? Some manuals say it should barely be touching...but that would entail that the float weight would be only suspended by its own balance wouldnt it? quote form the beta 300rr manual... Keep the carburettor on a 60° approx. inclined, so that float leans on the needle valve without pressing it. In this position the float edge should be parallel with the float chamber sealing surface
At a 60 degree angle the tang lightly touches the valve. There is actually quite a wide range of angle you can hold the carb at before the weight of the float starts to compress the spring. 60 degrees is about in the middle of this range and as such is a good angle to use as a reference. Moving the carb manually from 90 degrees to 0 degrees you'll easily be able to observe what happens. If you're aiming for a float height of 6.5mm then the float seam edge will be parallel with the float bowl surface. I prefer a float height of 7mm as it helps reduce spillage while riding and with this setting its a little off parallel.
90-60=30 degrees which is the angle of either carby end to the bench top. A good way of making a 90 degree triangle with opposite angles of 60 and 30 out of paper or cardboard. Is to start on a corner and measure one side say 2” or 5cm, then make the diagonal twice that 4” or 10cm. Now cut that out and the small angle will be 30 degrees which is the angle of the carb end to the bench, simples.
I have a 2022 Beta 200. It has a keihin pwk carb. The manual says the measurement from the carb body to the top of the float should be 16mm at a 60* angle. That’s seems way to much right? Should be in the 6-8mm range right? Thank you!
This is interesting, as Yamaha use this carb on their YZ250. Their method to adjust float height states to have the carb in an upside down position, not at 60 degrees
Interesting. I hadn't seen the Yamaha method before and just looked it up. Upside down will give a different float height to measuring when the carb is at 60 degrees. The Yamaha float height spec (when the carb is upside down) is listed as 5.5 to 7.5mm. I think the 60 degree measurement is a good method, being repeatable and continue to use it.
Both are acceptable but you will never get the float from the base to the top of the bottom of the float to measure 6.5-7mm, the float itself is taller than that.
@@TokyoOffroad Thank you very much man! What would i do without your knowledge. Also thank you for having very quality videos and being here on youtube!
I’m working on a carb from a 1975 Honda CB125S where the bowl gasket sits in the top half of the carb (the body of the carb that contains the float), and a small lip on the carb body is actually a little higher than the gasket surface (when the carb body is turned upside down). When measuring for the proper float height, do you remove the gasket and measure from the flat surface under the gasket, or measure from the gasket surface with the gasket in place, or measure from the surface of the lip?
Probably best to ask online in a CB focused forum for clarification regarding where to measure from. The Honda manual CB125S states "the height of the float above the carburetor body should be 24mm" and the photo in the manual isn't very clear...
Great video again! I have a problem while wheeling. Engine cuts off - can i increase the float level so the the carb has more fuel . Will this remedy the problem or i am fighting gravity? Thx in advance.
I have a question I was always told that the correct way to adjust the float height is to make sure that the floats must be parallel with the carb body when the floats close the valve. Is that also correct?
Great Video, thanks for sharing. I have a 2019 TM300EN with a Kiehin PWK 38, it's not the AIR STRIKER SHORT with STIC. But my manual calls for a float position of 16mm. Does float level and position mean the same thing? The reason I'M asking is because once my bike is warmed up it takes longer to start.
I don’t have any experience with TMs, but a regular 2-stroke if setup and running well it should start instantly when warmed up. Does it run OK once warm?
Yes it runs great. Only thing is it takes several seconds of cranking when warm.BTW if I set my float level per your video, then at 16mm the needle is bottomed out.
Found the float was grossly out of adjustment. Probably more like 20+ vs 16. I bent the tang back straight and rechecked. It was now 16. Thanks for all the help. I just dont understand how the only symptom was hard starting after warm. Bike ran great no hesitation, bogging ect. ?????
Thanks! Far from perfect, but I always try hard to make clear and understandable videos. I use a Canon 80D (with various lenses) with exposure and focus manually controlled and a Sennheiser AVX wireless microphone system.
@@TokyoOffroad Nice! I remember you started with a more "cheaper" model of Canon camera. The current setup really gives you the option to bring all the details video and audio wise.
Nir Hason - Yes, I used to use a Canon G7X compact camera. Video quality was OK, but there is no audio input for an external microphone, battery life was very short and the small screen made it difficult to focus manually with accuracy. The Canon 80D setup I have now is nice to use and I have an external LCD monitor making manual focus easy.
Hey man tanks for awesome videos. I got a te300 huskey from 2017 with mikuni tmx 38. Float hight set to 9mm. Needle 43-75 #2 S4 30 470 What is the float height ment to be? 7,5?
How by the stick metering rod in europe? France? Please help me ,my tc 125 2021 is impossible to tunne🤦♂️ But my 125 fantic 2021 have a tmx 38 to and have good feeling🤷♂️
Hi. Thanks for the great video. Does the same 6mm measurement apply to the PWK28 carbs? I just purchased the set of the PWK 28 for my K750 russian boxer, and i am wondering about the float value for them. Thanks.
my carb seems to leak when tilted regardless, I used the air blowing method and got a completely different result where the float looks parallel with the carb body at 60° and stops leaking air but when upside-down the float is no longer parallel the distance is more like 9 or 10 mill. ?
Thanks Mark, I’m going to check my brand new Beta 200rr this weekend. It has the same carb only 36mm. Do you happen to know factory 36mm setting? By the way my wheel weights for the 480rr are brilliant thank you.
It plays no role if the carb is tilted 60, 70 or 50 degrees, what counts is that valve is closed but the litte plunger (which is in fact a damper) on top of the needle valve is not compressed.
As I showed in the video when the I moved the carburetor by hand the float doesn't move significantly over a fairly broad range of angles. 60 degrees is probably close to the middle of the range. However, if you get closer to horizontal (float moves freely), or closer to vertical (valve damper spring starts to compress) the angle does matter. When trying to make accurate measurements it's a good idea to eliminate as many variables as possible and the holding the carb at a known angle is a good idea IMO. It's makes the measurements more repeatable. That's not to say that you can't get similar result by just holding it in your hand and eyeballing it.
My PWK also has 3 purple hoses. One of them is for fuel overflow. What are the functions of the other two? Are they for venting/overflow at different points from the carb?
Yes, that's correct. The upper most hoses which point are are vents and the ones at the side act as overflows when the bike is leaning over on it's side. The top vents you can route up underneath the tank if you fit longer hoses. I do this as there is a risk when doing deep water crossing if the vents hang down into water it can get sucked up into the carb.
@@TokyoOffroad if those vent lines can suck up water wouldn't they also suck in dust and clog things? I'm confused on what they actually vent. I can see it if the fuel level changed alot but the float should keep it close to constant. What am I missing?
@@otpipe Those pipes connect to the cast body of the carb, the side and top hoses are connected to the same channels on each side of the carb. When you lean the bike over like when you lay it down, the fuel in the carb can run out of those hoses to prevent the engine from flooding. If you really screw up and the bike gets inverted the top hoses will function the same way allowing fuel to exit the carb. In addition, fuel naturally evaporates, the pressure caused by evaporation in the bowl has to be vented somewhere or it pressurizes the carb and you get poor man's fuel injection.
@@TokyoOffroad i tried this on my 300exc pwk38 but found on a mx track that after a series of jumps the bike would rev when the throttle was shut. I assumed the fuel was shaken up the tube and fed back in when the bumps stopped. Very scary! Any thoughts on this?
@@jamesc2109 - What you experienced is certainly not normal. Do not ride the bike again until the problem has been identified and fixed. I suspect that either the slide is staying open for some reason after you release the throttle, or the carb is running lean and you're experiencing hanging idle. With the bike not running, try opening and closing the throttle. It should be smooth and when you release the throttle you should be able to hear the slide fully close (it makes a mechanical noise when it fully closes and hits the stop). It it's sticking check the throttle and throttle cable and clean or replace it there's an issue. If the problem is with the carburetor then disassemble and inspect and clean. Check that the cable is installed correctly in the slide. With the carb off the bike and throttle cable connected test by opening and closing the throttle and ensure that the slide movement is correct. If you suspect hanging idle (bike continues to rev very high after throttle is closed due to a lean condition) then there could be several different causes including carburetor not getting enough fuel (blockage), float level too low, carburetor setting is too lean.
The Mikuni TMX38 standard float height spec is 8.7mm +/-1mm. Out of the KTM factory the Mikuni typically have the fuel level too high. It’s a good idea to measure and set it as early as possible. In this video I show the Mikuni spec: th-cam.com/video/h3J6EUR45es/w-d-xo.html (1:24)
I have the TMX Mikuni 38 with the JD Jetting kit. Red Needle between 2k-7k. On a 19 ktm 300xc. I put the NGK TEIX plug here too. All is good. I am just reaching out and wondering if the Keihin PWK 38 with stic is been good to look into purchasing. Is this something you sell set up ready to purchase? Thank you.
Thanks for your interest. Yes, the Keihin 38 with STIC is a great upgrade from the Mikuni on the 300 and results in strong, responsive power which increases in a linear manner from bottom to top. Low rpm lugging performance is very good and the engine doesn't load up, even after extended periods of lugging. Top end is extended with more over rev. I set up each carb specifically for the customer's bike so the carb can be installed, idle speed set then ridden. Your ride elevation range is similar to mine (slight higher than mine) and I am able to use the same jetting year round and only tweak the airscrew setting. The STIC makes the carb far less sensitive to elevation and temp changes. I sell the kit on the Tokyo Offroad webshop here: www.tokyooffroad.com/product/stic-keihin-pwk-38mm-air-striker-short-kit/
I have a broblem with my carb settings.. once i start going downhill, my idle dramaticly drops for at least 30-50% i have mikuni tmx 38 on exc 300 2017. I have jd kit installed and i've already changed all the seals and gasket.. what would be the problem?
Yes, my experience with the Mikuni TMX 38 on KTMs is that from the factory the float level is set very high. This creates problems when going downhill (bike stalls) and also wastes a lot of fuel as it easily spills out from the overflow on rough ground. Definitely recommend checking and setting your float height. Mikuni recommend 8.7mm (which is what I used when I ran a Mikuni), but I bet yours is higher if it's never been adjusted...
@@TokyoOffroad it was set on 7.3mm ...i've set it on 8.2mm for the last ride and it was abit better going downhill (did not Stall as quickly) u reckon i should go for 8.7mm?
@@TokyoOffroad when the float is lowered to the specified level per the manual, is it when the needle valve just closes completely to take the measurement or when the small button is compressed as well? I’m guessing when only the needle valve closes, and the tab is just bumping the button - but I’m not clear on it. Thanks for your help!
@@BOPilot5517 The most accurate way is to check the float at when the carb is at 60degrees as shown in the video. But the quick and easy way is to rotate the carb until the valve just contacts the seat and check. If you continue to rotate the carb the button in the valve will eventually start to compress, but if you take your float height reading when the button is compressed it will give the wrong reading.
@@TokyoOffroad thank you. I meant to say keeping the carb at 60 degrees while the needle valve just seats. Excellent video by the way! Now if I just get my 1987 TRX250R to come up on the pipe I would be a happy. This is where the float adjustment came from. Trying to diagnose why it doesn’t want to come into the powerband.
Tokyo Offroad yeah ok, a guy on the forums is helping me figure out why I have a rich spot 0-1/4 range but mid and top rip like none other. Necj 3rd clip 38 pilot 168 main float is 8.5mm slide is 6.5 I’ve adjusted as from 1/2-3 gets better w higher but then comes the knock/ping over 2.5 60:1 golden spectro 91 junk ca pump 🤣 Rk tek low elevation insert. Going to try 35 pilot if it doesn’t fix it I’m going to pull head and put stock back on and try all over.
Jef Groff - what are the symptoms you’re experiencing of the low down richness? Yes, using a smaller pilot, and/or air screw adjustment should help if it’s running rich. Check that the needle valve is not damaged and seals properly (or the fuel level in the bowl will become higher and the engine will run rich). If damaged replace with a new one.
Tokyo Offroad so off idle through 1/4 throttle it hesitates/ surges and bogs once past that it cleans up and runs very very strong. If I wick the throttle in neutral it will bog and then rev out. Pipe has decent oil ring on tip after 20 min test ride and plug is blackish Mid to top are amazing. Need to add more up top even as it signed off early n got flat with a 165 main. Going back to 168 or 170.
Hi mate , I’ve got a 23 sherco se 300, pwk manual for mine says 16mm float height, at 16mm the float is running parallel to the carb body, should it be 7-8mm like you’ve described?if it gets set at that, the float most definitely won’t run parallel with the carb body, it would be slightly down,meaning a higher level in bowl, hope my description helps a bit, thanks luke
16mm? Or 6mm? 6mm is a standard float height for Keihin PWK. 7mm is a little lower and will help reduce fuel spillage and run very slightly leaner too.
Thanks for the reply mate 👍 Yeah 16mm the pdf says for a PWK 36! What do you recommend? I actually went on a ride today, while riding fire roads for a little while, bike was gutless(just top end) ,as if it was low on fuel, could the float height actually be to low and its emptying the bowl?
@@lukerobins5537 16mm doesn't make sense to me. They must be using a different way of measuring float height. If the float height is too low it will tend to run lean, lack power and feel like it's running out of fuel. My recommendation is to set the float height at 7mm as shown in the video, which will result in a good performance setting while minimizing fuel spillage.
@@TokyoOffroad if I could attach a photo of the PDF I would, yes it is confusing, it states the flat surface of the carb to top of float,as per your video! What you describe is spot on, as if it’s running out of fuel, I’m going to set it to your recommendation, it’s got to improve! I’ll report back to you 🤘 merry Xmas 🎄
I'll add the video idea to my list. To determine the health of the piston ring to cylinder seal my preferred method on a 2-stroke is to do compression testing. You could use a leak down tester to confirm if the head gasket is leaking (air would appear in the coolant) with the piston at TDC. To debug crankcase leaks you'd need to plug off the exhaust port and intake. Will definitely make a video sometime in the future...
Just curious if this applies to all Keihin carbs? Or does it depend on your make and model even though it uses Keihin. I Just bought a new 2020 beta 300 rr 2t. Anyone feel that the stock setting is accurate? Thanks
the stock settings on all BETAs is too high. Adjust as per this video and your fuel mileage will improve, you won't leak fuel when on the side stand and your bottom end response will be cleaner
LOL. I wouldn't describe my fingers as fat, but they are often greasy and are very hairy. The pointing tool is certainly preferable to looking at my fingers so I will continue to use it :-)
The machined surface which the float bowl seals on needs to be at 60 degrees to the horizontal (the bench in my case). If you look at the angle of machined surface it's closer to vertical than it is to horizontal. It's definitely 60 degrees in the video and not 30 degrees. And if you look carefully at the protractor tool I use to measure the angle you can see it's set to 60 degrees.
This should be the #1 video in a search result for anything like "Keihin float level." The instructions in the KTM manual aren't worded well, and this explanation clarifies in a *very* concrete and clear explanation. Well done, thank you! I'm disappointed that this only showed up in recommended videos days after searching for something exactly like this and not finding it the first time. Hopefully the algorithm will get it right for future searches!!
Pleased to hear that you like the video. I just added "Level" to the title of the video to help with searching. Thanks for the feedback
Not the hero we wanted, but the hero we needed!!! Everything explained so well and done in a profesiionally
Thank you for posting this video, I was having serious trouble fouling plugs on a used 2 stroke I purchased 8 months ago. The factory KTM manual's explanation of setting the float height was total garbage and caused the bike's pilot jet to function more like a pilot fountain. After watching this video I was able to accurately measure and set the float height which resolved my issue.
absolute best float level adjustment video so far, excellent job explaining everything, especially purposefully making the float stop at the wrong place
Very nicely done video, Mark. It is so hard to explain how to do the float height adjustment with just words. What I've found with the Keihin carbs after measuring it for years, is that the seam on the back side of the float will be nearly flush with the base of the carb body when the floats are at ~7mm's. I adjust it so the seam is just slightly recessed below the carb body and that gives me ~7mm's.
Unquestionably, the best explanation I have seen. Excellent, precise instruction.
6:55...A simple way of explaining this is to say that the float valve needs to be closed BUT you don't want the spring in the end of the valve compressed at all. :-)
Another awesome video!! The 7mm measuring block would be a great addition to your store!
Perfect help. Old gas had gummed up my float valve (completely stuck, open), so a good cleaning and height check was in order; much appreciated. PWM 38mm; very similar.
Pleased to hear that the video was useful.
What an absolutely phenomenal video. You my friend are a fantastic mechanic and teacher, as well as great at doing video presentations.
What I like best about this video is I’ve finally heard someone pronounce Keihin correctly. It’s not Keehin, it’s Kayhin. Whenever I pronounce it right shop people look at me like I’m dyslexic. Little do they know I lived in Japan for many years
Best float tutorial ever.
Thanks for making such a clear video. I hadn't ridden my TE250 in over a year. it started up very easily, but the carb was leaking a lot when sitting at idle or off with the gas valve open. This is will help me fix the problem!
Pleased that you enjoyed watching the video. It sounds like your float may be stuck, or there is some debris stopping the needle valve closing. Or the needle valve rubber might be damaged and need replacing. It should be easy to figure out what the cause is by taking off the float bowl and checking whether the float moves freely and if the needle valve is OK.
I always made it so the float is parallel with the float bowl sealing surface. Looks like it was fairly close to correct. Great video
Great video, just what I need with my cb650c restoration project. Carburetors are very complex. Thanks for knowledge.
Absolutely awesome explanation with the right amount of detail!!!
hans lefebvre good job,well said
Wow. Detailed video! Thorough explanation. Great instructor
Well your video was informative. What a big difference from my angle of 15 degrees and your 60 degrees. Good video and have a nice weekend.
Oh man, this is the video I needed. Thank you for being so clear and concise!
Glad it was helpful!
Wow...great video. Just great. Really appreciate this. Yet another new learning wrinkle in the brain from Tokoyo Offroad.
Pleased to hear that you enjoyed it.
Excellent presentation. Thanks for the lesson!
Great video, definitely the best one on TH-cam.
I want to say thank you, Your video was by far the easiest to understand and gave me the confidence I needed. Thank's
Deric Nichols - Thanks for the feedback and pleased that you found it useful.
@@TokyoOffroad I have a question, the brass hole that the needle valve seat in there are two small holes on the sides and one in the middle. is there supposed to be a small channel on the sidewall? can the brass needle valve orifice be replaced? I cant get it to stop leaking and i think the orifice is bad
Nice explanation 👍🏻 finally understand how to adjust the float correctly. Thank you
Super clearly explained and perfect close up images, my deep respect and lot of thanks for sharing your knowledge.
Excellent, thank you so much! I'm having issues with my carbs at the moment and for the life of me can't seem to get them to behave properly, no matter what I do, lol (noob here btw), especially with overflowing fuel when the bowls are fully. This will come in mighty handy, thank you!
If fuel is constantly overflowing then either the most likely causes are that the float valve is stuck, there is some dirt in the float valve, or the valve rubber is damaged and leaking. I recommend taking the carb off the bike, remove the float bowl and inspect the valve for damage, or debris.
finally a professional .......
Thank you for the details
Very comprehensive
Well done! Thanks for explaining things using the scientific method! Now i got my KTM dialed in i need to get my Husky 300 tuned.
So it doesn't matter how much the float tang is pressing on the needles suspension at this setting? Some manuals say it should barely be touching...but that would entail that the float weight would be only suspended by its own balance wouldnt it?
quote form the beta 300rr manual...
Keep the carburettor on a 60° approx.
inclined, so that float leans on the needle
valve without pressing it.
In this position the float edge should be parallel
with the float chamber sealing surface
At a 60 degree angle the tang lightly touches the valve. There is actually quite a wide range of angle you can hold the carb at before the weight of the float starts to compress the spring. 60 degrees is about in the middle of this range and as such is a good angle to use as a reference. Moving the carb manually from 90 degrees to 0 degrees you'll easily be able to observe what happens. If you're aiming for a float height of 6.5mm then the float seam edge will be parallel with the float bowl surface. I prefer a float height of 7mm as it helps reduce spillage while riding and with this setting its a little off parallel.
90-60=30 degrees which is the angle of either carby end to the bench top. A good way of making a 90 degree triangle with opposite angles of 60 and 30 out of paper or cardboard. Is to start on a corner and measure one side say 2” or 5cm, then make the diagonal twice that 4” or 10cm. Now cut that out and the small angle will be 30 degrees which is the angle of the carb end to the bench, simples.
Exceptional video, thank you.
Great video thank you for the great detail and description
Glad you enjoyed it!
Excellent video. Easy to follow and very informative. Many thanks for sharing
Hello, ktm exc 250 2005 two stroke with original keihin is the same dimension 7mm?
Chylo Racing - Yes, you can safely use the same float height as shown in the video
@@TokyoOffroad Thank You for reply🙂👍
Best video so far !
Excellent easy / detailed to understand video - well done.
I have a 2022 Beta 200. It has a keihin pwk carb. The manual says the measurement from the carb body to the top of the float should be 16mm at a 60* angle. That’s seems way to much right? Should be in the 6-8mm range right? Thank you!
I am here exactly for the same questing. Just got the 2024 beta 200rr and manual says 16mm. Did you end up setting the float height at 7mm?
@@allenmm yes 7-8mm did the trick. Much better gas mileage now
@@mmmx5109 Thank you very much. I just set it to 8mm and no more gas is dripping now. Braaap!
This is interesting, as Yamaha use this carb on their YZ250. Their method to adjust float height states to have the carb in an upside down position, not at 60 degrees
Interesting. I hadn't seen the Yamaha method before and just looked it up. Upside down will give a different float height to measuring when the carb is at 60 degrees. The Yamaha float height spec (when the carb is upside down) is listed as 5.5 to 7.5mm. I think the 60 degree measurement is a good method, being repeatable and continue to use it.
Both are acceptable but you will never get the float from the base to the top of the bottom of the float to measure 6.5-7mm, the float itself is taller than that.
Awesome explanation thank you. Will this 7mm height work for a PWK 36S 2014 KTM 200 xcw
Amazing video as always. Do you know if it will be the same 6-7mm float height for the standard Mikuni in the 2017-2018 KTM 2 strokes.
excellent explanation! meticulous and clear.
I know this is an old video, but how do you remove the brass hole that the float needle sits in?
Thank you this video helped me a lot!
Great video, but could you post a link to page where i can find the specification for float height to other models?
What carb do you have?
@@TokyoOffroad KEIHIN PWK 36S AG on my 2016 ktm exc 125
@@TokyoOffroad I am asking that because my bike always show low fuel, and i want to make sure is it set correcty
The float height setting method and spec is the same for your 36mm as the 38mm shown in the video.
@@TokyoOffroad Thank you very much man! What would i do without your knowledge. Also thank you for having very quality videos and being here on youtube!
So epic this is the king Kong of carb videos wow 👌
I’m working on a carb from a 1975 Honda CB125S where the bowl gasket sits in the top half of the carb (the body of the carb that contains the float), and a small lip on the carb body is actually a little higher than the gasket surface (when the carb body is turned upside down). When measuring for the proper float height, do you remove the gasket and measure from the flat surface under the gasket, or measure from the gasket surface with the gasket in place, or measure from the surface of the lip?
Probably best to ask online in a CB focused forum for clarification regarding where to measure from. The Honda manual CB125S states "the height of the float above the carburetor body should be 24mm" and the photo in the manual isn't very clear...
Great video again! I have a problem while wheeling. Engine cuts off - can i increase the float level so the the carb has more fuel . Will this remedy the problem or i am fighting gravity? Thx in advance.
Fantastic Content - deserves a new Sub!
Very good explanation!!
Thanks for sharing very helpful
I have a question
I was always told that the correct way to adjust the float height is to make sure that the floats must be parallel with the carb body when the floats close the valve.
Is that also correct?
Yes, that's true, but it's difficult to do it accurately that way. It's fine as a rough guide though...
Very good video and thank you for sharing it!
That's great! Many thanks
This is plain perfect and awesome.. thanks and bless up !!
Great Video, thanks for sharing.
I have a 2019 TM300EN with a Kiehin PWK 38, it's not the AIR STRIKER SHORT with STIC. But my manual calls for a float position of 16mm. Does float level and position mean the same thing?
The reason I'M asking is because once my bike is warmed up it takes longer to start.
Michael Pinkston -yes it means the same thing.
I don’t have any experience with TMs, but a regular 2-stroke if setup and running well it should start instantly when warmed up. Does it run OK once warm?
Yes it runs great. Only thing is it takes several seconds of cranking when warm.BTW if I set my float level per your video, then at 16mm the needle is bottomed out.
Found the float was grossly out of adjustment. Probably more like 20+ vs 16. I bent the tang back straight and rechecked. It was now 16. Thanks for all the help. I just dont understand how the only symptom was hard starting after warm. Bike ran great no hesitation, bogging ect. ?????
As usual, perfect detailed video - you're the maestro of accurate mechanic work!
What is your video/audio gear? :)
Thanks! Far from perfect, but I always try hard to make clear and understandable videos. I use a Canon 80D (with various lenses) with exposure and focus manually controlled and a Sennheiser AVX wireless microphone system.
@@TokyoOffroad Nice! I remember you started with a more "cheaper" model of Canon camera. The current setup really gives you the option to bring all the details video and audio wise.
Nir Hason - Yes, I used to use a Canon G7X compact camera. Video quality was OK, but there is no audio input for an external microphone, battery life was very short and the small screen made it difficult to focus manually with accuracy. The Canon 80D setup I have now is nice to use and I have an external LCD monitor making manual focus easy.
@@TokyoOffroad Tnx for investing for us! :)
Hey man tanks for awesome videos.
I got a te300 huskey from 2017 with mikuni tmx 38.
Float hight set to 9mm.
Needle 43-75 #2
S4
30
470
What is the float height ment to be? 7,5?
How by the stick metering rod in europe? France?
Please help me ,my tc 125 2021 is impossible to tunne🤦♂️
But my 125 fantic 2021 have a tmx 38 to and have good feeling🤷♂️
Well done! God bless.
Hi. Thanks for the great video. Does the same 6mm measurement apply to the PWK28 carbs? I just purchased the set of the PWK 28 for my K750 russian boxer, and i am wondering about the float value for them. Thanks.
That works, (reference mark and a gauge block), but I am just going to use a set of calipers.
Thanks for this! Any idea what the standard float height setting for a Keihin PD 26 is? I cant seem to find a tuning manual for it anywhere.
my carb seems to leak when tilted regardless, I used the air blowing method and got a completely different result where the float looks parallel with the carb body at 60° and stops leaking air but when upside-down the float is no longer parallel the distance is more like 9 or 10 mill. ?
Thanks Mark, I’m going to check my brand new Beta 200rr this weekend. It has the same carb only 36mm.
Do you happen to know factory 36mm setting? By the way my wheel weights for the 480rr are brilliant thank you.
I have a 2019 ktm 300 with the 38mm Keihin carb with out the stic metering block. Is the float height still at 6.5 to 8mm?
Yes, the spec is 6.5mm. I would aim for 6.5-7.0mm
It plays no role if the carb is tilted 60, 70 or 50 degrees, what counts is that valve is closed but the litte plunger (which is in fact a damper) on top of the needle valve is not compressed.
As I showed in the video when the I moved the carburetor by hand the float doesn't move significantly over a fairly broad range of angles. 60 degrees is probably close to the middle of the range. However, if you get closer to horizontal (float moves freely), or closer to vertical (valve damper spring starts to compress) the angle does matter. When trying to make accurate measurements it's a good idea to eliminate as many variables as possible and the holding the carb at a known angle is a good idea IMO. It's makes the measurements more repeatable. That's not to say that you can't get similar result by just holding it in your hand and eyeballing it.
What's the purpose of the dampener plunger in the needle?
thanks....nice & clear :)
Thank you 🙏
My PWK also has 3 purple hoses. One of them is for fuel overflow. What are the functions of the other two? Are they for venting/overflow at different points from the carb?
Yes, that's correct. The upper most hoses which point are are vents and the ones at the side act as overflows when the bike is leaning over on it's side. The top vents you can route up underneath the tank if you fit longer hoses. I do this as there is a risk when doing deep water crossing if the vents hang down into water it can get sucked up into the carb.
@@TokyoOffroad if those vent lines can suck up water wouldn't they also suck in dust and clog things? I'm confused on what they actually vent. I can see it if the fuel level changed alot but the float should keep it close to constant. What am I missing?
@@otpipe Those pipes connect to the cast body of the carb, the side and top hoses are connected to the same channels on each side of the carb. When you lean the bike over like when you lay it down, the fuel in the carb can run out of those hoses to prevent the engine from flooding. If you really screw up and the bike gets inverted the top hoses will function the same way allowing fuel to exit the carb. In addition, fuel naturally evaporates, the pressure caused by evaporation in the bowl has to be vented somewhere or it pressurizes the carb and you get poor man's fuel injection.
@@TokyoOffroad i tried this on my 300exc pwk38 but found on a mx track that after a series of jumps the bike would rev when the throttle was shut. I assumed the fuel was shaken up the tube and fed back in when the bumps stopped. Very scary! Any thoughts on this?
@@jamesc2109 - What you experienced is certainly not normal. Do not ride the bike again until the problem has been identified and fixed. I suspect that either the slide is staying open for some reason after you release the throttle, or the carb is running lean and you're experiencing hanging idle. With the bike not running, try opening and closing the throttle. It should be smooth and when you release the throttle you should be able to hear the slide fully close (it makes a mechanical noise when it fully closes and hits the stop). It it's sticking check the throttle and throttle cable and clean or replace it there's an issue. If the problem is with the carburetor then disassemble and inspect and clean. Check that the cable is installed correctly in the slide. With the carb off the bike and throttle cable connected test by opening and closing the throttle and ensure that the slide movement is correct. If you suspect hanging idle (bike continues to rev very high after throttle is closed due to a lean condition) then there could be several different causes including carburetor not getting enough fuel (blockage), float level too low, carburetor setting is too lean.
Great Tutorial! Thank you :-)
will this method work on a keihin pj28L , I can't find any information on how to adjust them
Wow such detail! Amazing info. Can i ask, do you know the float height for the Mikuni TMX 38. Thanks
The Mikuni TMX38 standard float height spec is 8.7mm +/-1mm. Out of the KTM factory the Mikuni typically have the fuel level too high. It’s a good idea to measure and set it as early as possible. In this video I show the Mikuni spec: th-cam.com/video/h3J6EUR45es/w-d-xo.html (1:24)
sooo what about round floats?? do you still measure off the bottom of those
for pwk 28 are the same settings?
Nice one, thank you so much!
I have the TMX Mikuni 38 with the JD Jetting kit. Red Needle between 2k-7k. On a 19 ktm 300xc. I put the NGK TEIX plug here too. All is good. I am just reaching out and wondering if the Keihin PWK 38 with stic is been good to look into purchasing. Is this something you sell set up ready to purchase? Thank you.
Thanks for your interest. Yes, the Keihin 38 with STIC is a great upgrade from the Mikuni on the 300 and results in strong, responsive power which increases in a linear manner from bottom to top. Low rpm lugging performance is very good and the engine doesn't load up, even after extended periods of lugging. Top end is extended with more over rev. I set up each carb specifically for the customer's bike so the carb can be installed, idle speed set then ridden. Your ride elevation range is similar to mine (slight higher than mine) and I am able to use the same jetting year round and only tweak the airscrew setting. The STIC makes the carb far less sensitive to elevation and temp changes. I sell the kit on the Tokyo Offroad webshop here: www.tokyooffroad.com/product/stic-keihin-pwk-38mm-air-striker-short-kit/
Is this setting good for a 98 cr250r
Jepp.. best on youtube!
How many millimeters is the piece that marks that level mark? Does anyone know?
I use a 7mm thick piece of aluminum
@@TokyoOffroad Thank you!
I have a broblem with my carb settings.. once i start going downhill, my idle dramaticly drops for at least 30-50% i have mikuni tmx 38 on exc 300 2017.
I have jd kit installed and i've already changed all the seals and gasket.. what would be the problem?
Yes, my experience with the Mikuni TMX 38 on KTMs is that from the factory the float level is set very high. This creates problems when going downhill (bike stalls) and also wastes a lot of fuel as it easily spills out from the overflow on rough ground. Definitely recommend checking and setting your float height. Mikuni recommend 8.7mm (which is what I used when I ran a Mikuni), but I bet yours is higher if it's never been adjusted...
@@TokyoOffroad it was set on 7.3mm ...i've set it on 8.2mm for the last ride and it was abit better going downhill (did not Stall as quickly) u reckon i should go for 8.7mm?
Wish it wasn’t such an old video, I have a question!?
What 's your question?
@@TokyoOffroad when the float is lowered to the specified level per the manual, is it when the needle valve just closes completely to take the measurement or when the small button is compressed as well? I’m guessing when only the needle valve closes, and the tab is just bumping the button - but I’m not clear on it.
Thanks for your help!
@@BOPilot5517 The most accurate way is to check the float at when the carb is at 60degrees as shown in the video. But the quick and easy way is to rotate the carb until the valve just contacts the seat and check. If you continue to rotate the carb the button in the valve will eventually start to compress, but if you take your float height reading when the button is compressed it will give the wrong reading.
@@TokyoOffroad thank you. I meant to say keeping the carb at 60 degrees while the needle valve just seats. Excellent video by the way! Now if I just get my 1987 TRX250R to come up on the pipe I would be a happy. This is where the float adjustment came from. Trying to diagnose why it doesn’t want to come into the powerband.
Mark.. what number slide are you running in this 38mm
I use a 6.5 slide. This size usually comes stock in the Keihin PWK 38mm Air Striker short carbs.
Tokyo Offroad yeah ok, a guy on the forums is helping me figure out why I have a rich spot 0-1/4 range but mid and top rip like none other.
Necj 3rd clip 38 pilot 168 main float is 8.5mm slide is 6.5
I’ve adjusted as from 1/2-3 gets better w higher but then comes the knock/ping over 2.5
60:1 golden spectro
91 junk ca pump 🤣
Rk tek low elevation insert.
Going to try 35 pilot if it doesn’t fix it I’m going to pull head and put stock back on and try all over.
Jef Groff - what are the symptoms you’re experiencing of the low down richness? Yes, using a smaller pilot, and/or air screw adjustment should help if it’s running rich. Check that the needle valve is not damaged and seals properly (or the fuel level in the bowl will become higher and the engine will run rich). If damaged replace with a new one.
Tokyo Offroad so off idle through 1/4 throttle it hesitates/ surges and bogs once past that it cleans up and runs very very strong. If I wick the throttle in neutral it will bog and then rev out. Pipe has decent oil ring on tip after 20 min test ride and plug is blackish
Mid to top are amazing. Need to add more up top even as it signed off early n got flat with a 165 main. Going back to 168 or 170.
Hi mate , I’ve got a 23 sherco se 300, pwk manual for mine says 16mm float height, at 16mm the float is running parallel to the carb body, should it be 7-8mm like you’ve described?if it gets set at that, the float most definitely won’t run parallel with the carb body, it would be slightly down,meaning a higher level in bowl, hope my description helps a bit, thanks luke
16mm? Or 6mm? 6mm is a standard float height for Keihin PWK. 7mm is a little lower and will help reduce fuel spillage and run very slightly leaner too.
Thanks for the reply mate 👍
Yeah 16mm the pdf says for a PWK 36! What do you recommend? I actually went on a ride today, while riding fire roads for a little while, bike was gutless(just top end) ,as if it was low on fuel, could the float height actually be to low and its emptying the bowl?
@@lukerobins5537 16mm doesn't make sense to me. They must be using a different way of measuring float height. If the float height is too low it will tend to run lean, lack power and feel like it's running out of fuel. My recommendation is to set the float height at 7mm as shown in the video, which will result in a good performance setting while minimizing fuel spillage.
@@TokyoOffroad if I could attach a photo of the PDF I would, yes it is confusing, it states the flat surface of the carb to top of float,as per your video! What you describe is spot on, as if it’s running out of fuel, I’m going to set it to your recommendation, it’s got to improve! I’ll report back to you 🤘 merry Xmas 🎄
great video
Can you make a video of how to leak down a two stroke engine?
I'll add the video idea to my list. To determine the health of the piston ring to cylinder seal my preferred method on a 2-stroke is to do compression testing. You could use a leak down tester to confirm if the head gasket is leaking (air would appear in the coolant) with the piston at TDC. To debug crankcase leaks you'd need to plug off the exhaust port and intake. Will definitely make a video sometime in the future...
Just curious if this applies to all Keihin carbs? Or does it depend on your make and model even though it uses Keihin. I Just bought a new 2020 beta 300 rr 2t. Anyone feel that the stock setting is accurate? Thanks
the stock settings on all BETAs is too high. Adjust as per this video and your fuel mileage will improve, you won't leak fuel when on the side stand and your bottom end response will be cleaner
Hi what is the size of carburetor?
The carburetor in the video is a Keihin PWK 38mm
How can i know how high is my if you need to but it to 6.5mm i have keihin pwk 36
And bike is 2011 ktm exc 125
I always heard it was adjusted at 45°
The Keihin PWK documentation I have states 60 degrees and I believe this to work well so haven't tried other angles.
Thank you
Thanks a lot!!
Thanks
wouldn't a factory mark for the float level on carb body be a great idea .
Correct method
Where can i get an 8mm block?
If you have a jointer, you can make one from wood.
How much money do you want for your 40 mm Mikuni carburetor?
250race - I don’t have a 40mm Mikuni. The only Mikuni I currently have is a TMX 38mm which is the stock carb taken off my 2017 KTM 250 EXC
@@TokyoOffroad
Does that have an interchangeable emotion tube in it?
Float level on the PWK28 yz65?
Thanks for using a pointing tool and not a greasy fat finger.
LOL. I wouldn't describe my fingers as fat, but they are often greasy and are very hairy. The pointing tool is certainly preferable to looking at my fingers so I will continue to use it :-)
Mikuni????
You put the Carb in a 30° angle not 60...
The machined surface which the float bowl seals on needs to be at 60 degrees to the horizontal (the bench in my case). If you look at the angle of machined surface it's closer to vertical than it is to horizontal. It's definitely 60 degrees in the video and not 30 degrees. And if you look carefully at the protractor tool I use to measure the angle you can see it's set to 60 degrees.
why is it so expensive???