Andy Mate, that is the best explanation I have ever heard, as to how a carb works, really interesting and easy to follow, I had a pretty good idea before, now I fully understand, I bet even a newbie spanner jock could deal with that, well done mate :)
+yankee doodle Awe shucks!! Thanks for the feedback mate. I left quite a bit out and having re-watched it I wish I had taken the time to explain a few more things and been a bit more accurate about some of the statements.
Thank you so much Andy. Im a first time rider/bike owner and my carbs have causing me issues. This helped me understand my Mikuni carbs so much more! You're channel is awesome, thanks again!
well explained video.i just bought a yamaha xs400 1981 .having all sorts of trouble, starting one day and not starting the nxt.was going to raise the needle one position but never thought to change the jet size by 5.ill give this a go 👍
Your video's are amazing .. I just picked up a 1981 xs 1100 trans Canada and will be refurbishing it similar to yours in the next couple years . I am watching every one of them
I have been looking for a video like this for years. I have an xs360. I'm extremely handy in most places in my life but my deficiency is in engines and carbs. Though I have not completed the work at the time of writing this, I'm confident saying this has and will be the most helpful video and bringing this old beauty back to life. I know you have a ton of xs360 in your neck of the woods but they were a one-year bike here in the states. Very few left and the ones that are left have been gutted of original parts.
Exellent!! that is a great video with useful info, love it! For people like me with no dyno i can finally go ahead and tune that engine the right way. thanks man!
+Frans Terhorst Thanks Frans. There was a fair bit of important info not covered in that video. Make sure you check out episode 51, it will be up on TH-cam in a little over 3.5 hours time. Andy
I will watch and learn! I have at least 3 bikes that will get the treatment, i learned the hard way that a lean mixture can result in melted pistons and the like , you just explained what went wrong there..knowledge is power!
Excellent I have pods and aftermarket exhaust on my 900 now it is going to run even better it has always had that backfire when you slow down by the way it's a z1 Kawasaki thank you very much great info here
AMAZING!!!!! I have started working on my XS1100 and have been a little intimidated to switch to Pods but after watching this video I now know exactly what is necessary. I will be pulling the carbs and giving them a thorough cleaning at which time I will re-jet them and then check the plugs. Thank you Andy keep posting this great content. Cheers
Thanks mate, a word to the wise. Make sure you don’t remove the capability to replace your airbox until you are happy with it. There are a couple of other videos you may want to watch as well, I will link them below.
Hi Andy, Good Video, thanks :-) I am going to have a go at making my own exhaust system, I have a few books here at home that I will source information from, if I find this to be too hard then I will just buy one from the shelf, the main reason that I want to have a got at making my own is because I can't yet decide how the exhaust will look, I am thinking of the silencer to exit under the seat, decisions, decisions. Just on with my seat pod, gonna have a go at making my own out of sheet steel, video will be updated soon Jason
+Jason Parker Cool Jase. I will look forward to seeing it all. I worked in breweries for 20 years, I was the engineering manager here in Hobart, and I had access to all the stainless steel and the equipment to do the job, I'm pretty handy with a TIG welder. But alas, I no longer have that luxury. I would have made one if I had access to the gear, it's not that hard.
Andy, For more then 2 months I've been chasing a major lean condition problem on my XJ650 running the stock hitachi hsc32 carbs, the carbs have been removed more then 30 times, gone through, changes made and plugs removed and read multiple times a day, heat ranges changed, ect ect. the whole process of looking for a solution to the problem has been based on the same basic core premise I've used for 40 years with carbureted bikes, mixture controlled by throttle positions, idle to approx 1/4 throttle is idle/pilot circuit, 1/4 thru approx 2/3 slide needle, and 2/3 thru full throttle main jet. I know they over lap but I've simplified it to save time but you get the idea. during this solution search venture a quandary has surfaced that I've never noticed before and not sure how to answer, with those basic rules in mind, when i'm running at a constant 65 mph with the motor running at 5000 rpm's and where the engine is running extremely lean, I look at the throttle position and it is at 1/16 or less, does that mean at 5000 rpm and above if i'm running at a constant speed with less then a 1/4 throttle position my main jets and needle positions are irrelevant and my bike is running purely on the pilot circuit? with using the throttle positioning as the rule, when I increased my main jet size from the stock of 110 to 116 trying to richen up the top end, why did it make engine run sloppy rich below 3500 rpm's but not effect the lean condition above 4000rpm's, NO AIR LEAKS! there is something about CV carbs that makes the old guidelines not apply but I can't figure out exactly what it is other then it has something to do with the vacuum operated slide, any input????
Great question, I will see if I can add some light. The thing with CV carburetors is that the throttle position is not proportional to the fuel metering because the carburetor varies the mixture in response to manifold conditions. I guess you could compare it to a fuel injection setup because the linear association is with the air metering and not the fuel. It’s important to realise, as you have touched on here, that there is not only overlap but more so a “staging” effect of the different circuits within the carburetor. As the diaphragm lifts it introduces the needle jet circuit and that increase in fuel is in addition to the pilot jet supply. So while the pilot jet has the greatest influence from idle to 1/4 throttle it still supplies fuel throughout the entire delivery to WOT. My advice to you would be to focus on needle position and also one of the most overlooked areas, the fuel bowl. Try increasing the level slightly in the fuel bowl and ensure that the bowl is breathing properly. This is the greatest problem when not running the factory air box because these carbs need to have a balanced condition between the pressure in the bowl and the intake. I hope this helps, Andy
oh i guess i didn't mention that I'm running the stock airbox and filter and almost stock exhaust with just the outlet diameter opened up by 1/2 inch and replaced the vacuum operated petcock with a gravity fed one. out of desperation to try and get the top end to run rich I did a kinda strange experiment last night, couldn't decide whether to try 1 washer or 2 under the slide needle so I used 1 washer on cylinders 1 & 2 and used 2 washers with 3 & 4, man did it run like crap but I managed to get a couple 5000 rpm runs in and for the first time in 2 months the plugs weren't bright white at 5000 rpm, the single washer carbs were rich but with a hint of caramel while the 2 washer carbs were completely black, but this is with the 116 over sized jets, going to go back to the stock 110 jets and do the same experiment also recheck the bowl vent and increase the fuel level by 2 mm here's a question, hitachi slides have a small raised piece inside the slide to make the needle pitch downward at an angle but this also causes the needle to bind sometimes when a washer is under it, can you see any reason why that raised piece couldn't be grinded off so the needle hangs straight down like other carburetor slides?
Hello Andy, Appreciate you sharing your knowledge. Quick question, if I install pod filters on my 83 yamaha maxim750, can I get away with just increasing gas flow and/or restricting air flow? If so, how? I'd greatly appreciate your help. Thank you sir
Andy when you say increase main jets by 2.5 with stock exhaust and going pods would that be 150 to 152.5. I have a suzuki gs650 I've switched to pods. wondering if any the other jets need to be increased in size also also. it seems to idle fine with the current pilot jets and idle jets with pods on it. it just wont accelerate past 45mph now with the pods. it acts like it runs out of gas.
Does a straight or angled pod filter matter? I read somewhere online that angled pod filters are preferable since they have a downdraft effect of the air going to the carb?
First off I love your videos, you’re pretty unrivaled as far as raw knowledge and understanding of these bikes on TH-cam. I’m actually building a 1972 cb350, with the stock keihin carbs. I’m at the near end of the build but having difficulty with the carb tuning, any suggestions on jet sizes? The stock idle jet is #35, main is #68, secondary is #105. I just switched over to k&n pod filters btw and upgraded to a #35 idle, #75 main and 115 secondary. Haven’t tried starting her up yet as I’m in Michigan and it’s currently pretty cold out but I’ll give her a kick soon.
hello buddy. I've put pods on cb 250 and it won’t run Smoothly when you blip the throttle. tried air screw in and out no difference. Messed about trying things with the pods. So guess it’s jets next. At full 1/8 to full throttle is good. any suggestions what to go for its a keihin vb30a main jet 105 main pilot jet 72 and standard pilot jet under it let me know cheers
I've been tuning the Carbs on my 82 750 Maxim for a Week or so, kinda learning as I go. And ive been going off the build up on the Electrode in the Center. If it's not mostly white is that an indication I'm Rich? My Electrode is Medium Tanish color, almost Orange in some places..
I removed my baffles and intend to put high flow pod filters on the carbs for my 1982 XJ1100. What jets are you running now? Love the videos. You have saved my butt a few times now.
+scottleepeters g'day Scott, I am not using these carburetors anymore. I am using Mikuni RS36 flatslides. I was using standard pilot jets and 147 main jets. Needle lifted one position.
Sounds great. I'm tearing it down now for the transmission fix, but this is next on the list. I'm going to do a lot more research on this yet but your carb videos have already given me a pretty good idea of what to expect. Thanks for the response! Your bike is my screensaver at work for inspiration.
+scottleepeters lol that's pretty cool, thanks mate. Ultimately CV carbs will play up off idle and up to about 1/3 rd throttle with pods. But my view has always been "who cares?" As long as I don't have to ride it every day I can live with compromise. I have other bikes for reliability. Thanks for watching, Andy
Hey! Great video! I was wondering, when you say "increase main jet by 5 sizes", do you mean a 125 -> 130, or to go 5 incremental sizes up, like a 125 -> 137.5? I currently have an 83 VT500c, moved to short pod filters. Stock is 38 pilot, 112/122 mains (rear is richer). I tried 42 pilots and 135 mains, and it's too rich at WOT, and hot startups. Switched to 40 pilot and 132 mains, going to try that again after the rain is gone. (I have straight baffle mufflers as well as pod filters). Any advice is appreciated, thanks!
Only to a point and it only effects the pilot circuit. When the size of the opening at the screw out strips the pilot jet size adjusting the screw will have no impact. Also at 3/4 throttle and above your main jet will be too small and will lean out.
I have a 91 750cc intruder. and I notice I have a tube then the air box. so I'm going to attached the pod filter at the end of the other side of the tube. hoping I dint have to re jet anything . cuz I HATE that air box. needs to go Ima turning it onto a bobber all frame hidden wires
G'day Rene, it is a bit ambiguous, that would be up to a 97.5 in your case. A word to the wise, expect issues. While you can run CV Carbs on pods, it takes time and effort to get them to perform, you are dramatically changing the track length and the manner the air is delivered. Don't remove the option to replace your airbox if needed.
Thanks for the explanation! Very helpful video! I want to install pods and a shorty exhaust on my 1992 CB750 Nighthawk - every time I try to look up info online, people keep saying that the Keihin CV carbs are a PITA to run on pods, and that getting these bikes to run properly across the rev range without factory airbox is nearly impossible. Any advice/insights on getting a proper setup?
+akumabito2008 There is an element of truth in what you hear. These are Mikuni, not Keihin, but CV carbs are problematic on PODs. PODs don't deliver the air in a way that the carbs like and they become fluttery. The shared airbox gets rid of a lot of pulsing and they deliver the air through velocity stacks, which smooth's out the air delivery. My advice would be to fit your pods to the end of your factory velocity stacks. If you don't like that look you can fashion a restrictor to fit inside the POD, out of a Coke Can or similar, that will act as a type of velocity stack and restrict the air flow at the same time. I have heard that this is quite successful. I never got to test the theory as my carbs were badly damaged internally and the pilot circuit was oversized and uncontrollable. I ended up fitting these th-cam.com/video/5eUnbVAp8hI/w-d-xo.html
+Andy's Motorcycle Obsessions Thanks for the quick reply! the airbox and stacks on my bike need to go - I want to convert my bike into a replica of the one Classified Moto build for the TV show the Walking Dead (www.classifiedmoto.com/motorcycles/daryls-bike/) I want to get as close as possible, while still being practical and rideable. The filters I end up using don't need to be 100% screen accurate, but the airbox needs to go to make space for the bag.
+akumabito2008 I just checked that bike out, wow!!!! I love it. Mate, they have done a very clever thing with the airbox on that. They have fabricated a low profile shared airbox. That would not be too hard too duplicate and it would definitely help the carbs cope with a smooth operation. You would need to fabricate the tubes into the carbs to be as long as possible and fit a custom made foam filter but definitely doable, I just wish I'd have thought of it.
There are loads of cool little details on that bike. It'll be a fun challenge to try and replicate as many as I can. I'm looking into custom airboxes at the moment. They definitely seem like a better option than pods. I think they look better, too. Steel dragon is making some that look good: www.steeldragonperformance.com/air_boxes_7.html Definitely considering the diy route as well..
instead of pulling the plugs between each run, would you suggest getting a Gunson Colortune tool? and adjust the fuel mixture according to flame color?
@@ANDY5 yes exactly!!! awesome...now that only tunes the pilot circuit correct? will it have an affect on the main circuit during WOT or even 3/4 throttle?
Pls explain, if this pod type of carburetor fitted outside of a motorcycle frame without any cover ,can it ride on a rainy day ? will the water comes into the engine through the filter ?Thank you.
+Andy's Motorcycle Obsessions Thank you for the quick answer. Can you provide me the exact jets that you bought? I use the same POD Filters that you use and combined it to a 4-1 from marshall. the original setup, that can be found in the carb repair set is not usable and so i hope your setup runs better. Have a nice day - Stefan
I am using the standard pilot, 42.5 i think??? 147.5 on the main jet and needle lifted one position. Everything is new. New jets, new needles, new emulsion tubes and new diaphragms. It's not tested and tuned yet. I'll let you know how i get on. May need bigger Mains yet.
+Andy's Motorcycle Obsessions Thank you Andy, i will wait for your results. At the moment it is too cold to test my project and i have no dyno here. As you can hear in my videos, my bike runs very bad.
+Stefan Knierim Stefan your atmosphere will almost certainly be different to Tasmania so what works for me may not work for you. A couple of things to consider. 1. If you still have vent hoses connected to your carbs, remove them. I know it will open them up for debris ingress but I have been told they can have an impact. Leave the Tee's just remove the hoses. 2. Ensure that you have absolutely no vacuum leaks. 3. Make sure your valve clearances are set correctly. 4. Make sure you have good compression. 5. You can simulate the original air box conditions, sort of, by cutting some beer can aluminium and fitting it into the inside of the pod filters effectively restricting their intake and forming a kind of velocity stack to help smooth the air flow into the carbs. You want to cut a piece and wrap it around the inside of the filters blocking approximately 2/3 of the length of the filter, from the carb towards the front of the filter. Am I making sense? 6. Make sure your pods are not blocking the air jets on the carb intake, your pods look better than mine. Mate you have done a great job, she looks amazing. Try to find a local 'Old School' mechanic that can help. Good luck, keep us up to date.
Andy If one of my four diaphragms has burst and requires replacement. Am I ok only replacing the burst one or do I need to replace all four diaphragms?
In my yamaha xj 600 90- it had 105 jets, but i installed pods and chopped the exhaust and installed better flowing mufflers, i played whit the jets for a while and the best air fuel mixture was achieved whit 115 jets..... idle is much ruffer now because i didnt know i should change the idle jet..... power band is now weird too but pulls from the top end really good. So what idle jets i should try first in your opinion. Also winter is coming to finland soon so im going to pull the engine out and change the cam chain and anything else if needed, im thinking should i polish the combustion chamber ? is there any good doing that on cinda stock bike......Sorry for any typos
+TT GarageRat G'day mate. 115 is about four jets bigger than 105's I think. Generally speaking you should increase your pilot jet by one size for every three on the main jet. So you should probably try one size bigger than what you have now. Jump on the Jets R Us website jetsrus.com/index.html and have a look. Pretty sure your bike has a Mikuni BDS26 carb so look for the BDS series on their web site. Good luck, let us know how you get on. Andy
+TT GarageRat Sorry mate I didn't comment on your question about the combustion chamber. Yes it is worth doing. The best approach is to get hold of a second hand set of valves and a clear piece of poly carbonate plastic, or similar, that is big enough to cover one chamber. Remove your good valves, be sure to mark where they came from. The function of the old second hand valves is to protect the seats when you are in there with a die grinder. Wipe some grease around the valve seats and insert the used 2nd hand valves, just put them in the valve guide and don't worry about fitting the springs or collets, and screw in a spark plug. Next take your piece of plastic and drill two 3mm holes in the centre, side by side. Turn the head, chamber side up, and level it. Wipe some grease around the outside edge of the chamber and place the plastic over the chamber. Then use a syringe to inject water, add a bit of food dye for colour, and measure the volume of each chamber. Find the one with the most volume and polish it first, known as "padding the chamber." Then work on each chamber until it holds the same volume as the first. This is called "CCing the chambers." The polish helps reduce carbon build up and aids air flow and matching the CC's (Cubic Centimeters) is one stage of "Blueprinting" an engine and ensures that you have continuity across all chambers. Be aware of removing too much material from the largest chamber as you will start impacting the compression ratio. I hope that makes sense???? Good luck.
+Andy's Motorcycle Obsessions P.S. you only need enough 2nd hand valves to work on one chamber at a time. Just move them from chamber to chamber. It's a good days work to do this job.
+Andy's Motorcycle Obsessions Sorry to keep adding but I forgot to mention that you should lay your head gasket over and mark the head with a permanent marker so that you don't grind, polish in the area it needs to seal. Right!!! That's it...I hope :)
Andy Mate, that is the best explanation I have ever heard, as to how a carb works, really interesting and easy to follow, I had a pretty good idea before, now I fully understand, I bet even a newbie spanner jock could deal with that, well done mate :)
+yankee doodle Awe shucks!! Thanks for the feedback mate. I left quite a bit out and having re-watched it I wish I had taken the time to explain a few more things and been a bit more accurate about some of the statements.
Andy's Motorcycle Obsessions You know the old saying mate,,, less is more! :)
Dude. What an amazing video! Learned so much, thank you!
Awesome diagram and explanation, always happy to see legit info being put out there. I'll be sure to link people to your video in the future. Thanks!
8
And now I actually understand how a carb works. Amazing! Many thanks.
Thank you so much Andy. Im a first time rider/bike owner and my carbs have causing me issues. This helped me understand my Mikuni carbs so much more! You're channel is awesome, thanks again!
give this man a million dollars to build bikes! excellent material thank you for posting. im going to be adding pod filters to my 1995 gsxr 750.
Yes do that please, is build two for that much 😂
This is the best carb video out there. Great job.
Probably the best summary of this I've found so far. Great video.
Good summary but what would the out come be.maybe ok with some bikes and not others 🤔
well explained video.i just bought a yamaha xs400 1981 .having all sorts of trouble, starting one day and not starting the nxt.was going to raise the needle one position but never thought to change the jet size by 5.ill give this a go 👍
Your video's are amazing .. I just picked up a 1981 xs 1100 trans Canada and will be refurbishing it similar to yours in the next couple years . I am watching every one of them
I have been looking for a video like this for years. I have an xs360. I'm extremely handy in most places in my life but my deficiency is in engines and carbs. Though I have not completed the work at the time of writing this, I'm confident saying this has and will be the most helpful video and bringing this old beauty back to life. I know you have a ton of xs360 in your neck of the woods but they were a one-year bike here in the states. Very few left and the ones that are left have been gutted of original parts.
hi.did you ever get your bike running goid🤔
This is amazingly clear and helpful. I feel as though I might now understand how carbs work. Thanks mate 👍👍👍
All good things to you mate. So grateful for this.
Amazing video and explanations. Thanks for taking the time.
On the way to the bank to contribute to the cause. This is excellent, thanks!
Fantastic Video Andy . well done mate.
Thanks for your help this clip was a great eye opener , These Irish eyes will keep on watching thanks again
Just started watching this. I’m hooked at intro man. Brilliant.
This video alone is worth subscribing.
Exellent!! that is a great video with useful info, love it! For people like me with no dyno i can finally go ahead and tune that engine the right way. thanks man!
+Frans Terhorst Thanks Frans. There was a fair bit of important info not covered in that video. Make sure you check out episode 51, it will be up on TH-cam in a little over 3.5 hours time. Andy
I will watch and learn! I have at least 3 bikes that will get the treatment, i learned the hard way that a lean mixture can result in melted pistons and the like , you just explained what went wrong there..knowledge is power!
Excellent I have pods and aftermarket exhaust on my 900 now it is going to run even better it has always had that backfire when you slow down by the way it's a z1 Kawasaki thank you very much great info here
Andy. Thanks great video, the best lesson I've seen so far. Brilliant thanks again, geoff
Awesome video. Thorough and explanatory. Thank you
AMAZING!!!!! I have started working on my XS1100 and have been a little intimidated to switch to Pods but after watching this video I now know exactly what is necessary. I will be pulling the carbs and giving them a thorough cleaning at which time I will re-jet them and then check the plugs. Thank you Andy keep posting this great content. Cheers
Thanks mate, a word to the wise. Make sure you don’t remove the capability to replace your airbox until you are happy with it. There are a couple of other videos you may want to watch as well, I will link them below.
th-cam.com/video/YiWnXu0KNCs/w-d-xo.html
th-cam.com/video/Vt6HtsggcqU/w-d-xo.html
Excellent video Andy,well explained.
how great an explanation....cheers
Cheers Eric, and thanks for tuning in. It must be said, however, that pods and CV's don't play well together. You have to accept some compromise
Cheers Andy I forgot to say Im watching all the basket case videos top videos. Geoff
Hi Andy, Very Informative and well explained mate.
+oozuk Thanks Steve
Hi Andy,
Good Video, thanks :-)
I am going to have a go at making my own exhaust system, I have a few books here at home that I will source information from, if I find this to be too hard then I will just buy one from the shelf, the main reason that I want to have a got at making my own is because I can't yet decide how the exhaust will look, I am thinking of the silencer to exit under the seat, decisions, decisions.
Just on with my seat pod, gonna have a go at making my own out of sheet steel, video will be updated soon
Jason
+Jason Parker Cool Jase. I will look forward to seeing it all. I worked in breweries for 20 years, I was the engineering manager here in Hobart, and I had access to all the stainless steel and the equipment to do the job, I'm pretty handy with a TIG welder. But alas, I no longer have that luxury. I would have made one if I had access to the gear, it's not that hard.
great job Andy , this was helpful.
+NorthernSutherner Thanks mate.
Wow.. thank you !!! Amazing explanation.
Great vid.Foam filters or k&n style for performance?
Andy, For more then 2 months I've been chasing a major lean condition problem on my XJ650 running the stock hitachi hsc32 carbs, the carbs have been removed more then 30 times, gone through, changes made and plugs removed and read multiple times a day, heat ranges changed, ect ect. the whole process of looking for a solution to the problem has been based on the same basic core premise I've used for 40 years with carbureted bikes, mixture controlled by throttle positions, idle to approx 1/4 throttle is idle/pilot circuit, 1/4 thru approx 2/3 slide needle, and 2/3 thru full throttle main jet. I know they over lap but I've simplified it to save time but you get the idea. during this solution search venture a quandary has surfaced that I've never noticed before and not sure how to answer, with those basic rules in mind, when i'm running at a constant 65 mph with the motor running at 5000 rpm's and where the engine is running extremely lean, I look at the throttle position and it is at 1/16 or less, does that mean at 5000 rpm and above if i'm running at a constant speed with less then a 1/4 throttle position my main jets and needle positions are irrelevant and my bike is running purely on the pilot circuit? with using the throttle positioning as the rule, when I increased my main jet size from the stock of 110 to 116 trying to richen up the top end, why did it make engine run sloppy rich below 3500 rpm's but not effect the lean condition above 4000rpm's, NO AIR LEAKS! there is something about CV carbs that makes the old guidelines not apply but I can't figure out exactly what it is other then it has something to do with the vacuum operated slide, any input????
Great question, I will see if I can add some light. The thing with CV carburetors is that the throttle position is not proportional to the fuel metering because the carburetor varies the mixture in response to manifold conditions. I guess you could compare it to a fuel injection setup because the linear association is with the air metering and not the fuel. It’s important to realise, as you have touched on here, that there is not only overlap but more so a “staging” effect of the different circuits within the carburetor. As the diaphragm lifts it introduces the needle jet circuit and that increase in fuel is in addition to the pilot jet supply. So while the pilot jet has the greatest influence from idle to 1/4 throttle it still supplies fuel throughout the entire delivery to WOT. My advice to you would be to focus on needle position and also one of the most overlooked areas, the fuel bowl. Try increasing the level slightly in the fuel bowl and ensure that the bowl is breathing properly. This is the greatest problem when not running the factory air box because these carbs need to have a balanced condition between the pressure in the bowl and the intake. I hope this helps, Andy
oh i guess i didn't mention that I'm running the stock airbox and filter and almost stock exhaust with just the outlet diameter opened up by 1/2 inch and replaced the vacuum operated petcock with a gravity fed one. out of desperation to try and get the top end to run rich I did a kinda strange experiment last night, couldn't decide whether to try 1 washer or 2 under the slide needle so I used 1 washer on cylinders 1 & 2 and used 2 washers with 3 & 4, man did it run like crap but I managed to get a couple 5000 rpm runs in and for the first time in 2 months the plugs weren't bright white at 5000 rpm, the single washer carbs were rich but with a hint of caramel while the 2 washer carbs were completely black, but this is with the 116 over sized jets, going to go back to the stock 110 jets and do the same experiment also recheck the bowl vent and increase the fuel level by 2 mm
here's a question, hitachi slides have a small raised piece inside the slide to make the needle pitch downward at an angle but this also causes the needle to bind sometimes when a washer is under it, can you see any reason why that raised piece couldn't be grinded off so the needle hangs straight down like other carburetor slides?
Hello Andy,
Appreciate you sharing your knowledge.
Quick question, if I install pod filters on my 83 yamaha maxim750, can I get away with just increasing gas flow and/or restricting air flow? If so, how? I'd greatly appreciate your help. Thank you sir
The amount of bullshit I've watched and read before finding this; the holy grail of pod and carb info, is unreal.
Thank you sir.
Great explanation! I have a zxr250 and man the carbs on that thing give me the real shits! Cheers.
Andy when you say increase main jets by 2.5 with stock exhaust and going pods would that be 150 to 152.5. I have a suzuki gs650 I've switched to pods. wondering if any the other jets need to be increased in size also also. it seems to idle fine with the current pilot jets and idle jets with pods on it. it just wont accelerate past 45mph now with the pods. it acts like it runs out of gas.
7:32 those are considered two? I'd think it was one circuit there
Does a straight or angled pod filter matter? I read somewhere online that angled pod filters are preferable since they have a downdraft effect of the air going to the carb?
First off I love your videos, you’re pretty unrivaled as far as raw knowledge and understanding of these bikes on TH-cam. I’m actually building a 1972 cb350, with the stock keihin carbs. I’m at the near end of the build but having difficulty with the carb tuning, any suggestions on jet sizes? The stock idle jet is #35, main is #68, secondary is #105. I just switched over to k&n pod filters btw and upgraded to a #35 idle, #75 main and 115 secondary. Haven’t tried starting her up yet as I’m in Michigan and it’s currently pretty cold out but I’ll give her a kick soon.
I think that sounds about right to get you in the ballpark
hello buddy. I've put pods on cb 250 and it won’t run Smoothly when you blip the throttle. tried air screw in and out no difference. Messed about trying things with the pods. So guess it’s jets next. At full 1/8 to full throttle is good. any suggestions what to go for its a keihin vb30a main jet 105 main pilot jet 72 and standard pilot jet under it let me know cheers
I've been tuning the Carbs on my 82 750 Maxim for a Week or so, kinda learning as I go. And ive been going off the build up on the Electrode in the Center. If it's not mostly white is that an indication I'm Rich? My Electrode is Medium Tanish color, almost Orange in some places..
Oh I'm running a Mac 4 into 1 with an intact Baffle along with the Factory Airbox, and I Jetted it out from #122 to #125..
I removed my baffles and intend to put high flow pod filters on the carbs for my 1982 XJ1100. What jets are you running now?
Love the videos. You have saved my butt a few times now.
+scottleepeters g'day Scott, I am not using these carburetors anymore. I am using Mikuni RS36 flatslides. I was using standard pilot jets and 147 main jets. Needle lifted one position.
Sounds great. I'm tearing it down now for the transmission fix, but this is next on the list. I'm going to do a lot more research on this yet but your carb videos have already given me a pretty good idea of what to expect. Thanks for the response! Your bike is my screensaver at work for inspiration.
+scottleepeters lol that's pretty cool, thanks mate. Ultimately CV carbs will play up off idle and up to about 1/3 rd throttle with pods. But my view has always been "who cares?" As long as I don't have to ride it every day I can live with compromise. I have other bikes for reliability. Thanks for watching, Andy
Thank you.
Hey! Great video! I was wondering, when you say "increase main jet by 5 sizes", do you mean a 125 -> 130, or to go 5 incremental sizes up, like a 125 -> 137.5? I currently have an 83 VT500c, moved to short pod filters. Stock is 38 pilot, 112/122 mains (rear is richer). I tried 42 pilots and 135 mains, and it's too rich at WOT, and hot startups. Switched to 40 pilot and 132 mains, going to try that again after the rain is gone. (I have straight baffle mufflers as well as pod filters). Any advice is appreciated, thanks!
hi did you ever try the bike with these larger jets 🤔
Can I adjust the fuel to air mixture screw instead of buying different jets?
Only to a point and it only effects the pilot circuit. When the size of the opening at the screw out strips the pilot jet size adjusting the screw will have no impact. Also at 3/4 throttle and above your main jet will be too small and will lean out.
do you have a video that explains why the engine runs only when choke is on ?
very helpful thank you!
Adam, what size are the pod filters?
I have a 91 750cc intruder. and I notice I have a tube then the air box. so I'm going to attached the pod filter at the end of the other side of the tube. hoping I dint have to re jet anything . cuz I HATE that air box. needs to go Ima turning it onto a bobber all frame hidden wires
Thats sux. These bikes are crap! I sightlines Runing great for $600. Turn it into a bobber and selling for 2k.I.hate this whole bike set up
Hi Andy, at first thanks for your great videos. what do you mean with 2.5 sizes greater than original? for example my main jet is 95.
G'day Rene, it is a bit ambiguous, that would be up to a 97.5 in your case. A word to the wise, expect issues. While you can run CV Carbs on pods, it takes time and effort to get them to perform, you are dramatically changing the track length and the manner the air is delivered. Don't remove the option to replace your airbox if needed.
Mikuni jets are in increments of 2.5. So 2.5 is one jet size larger and 5 is 2 jet sizes larger
Thanks for the explanation! Very helpful video!
I want to install pods and a shorty exhaust on my 1992 CB750 Nighthawk - every time I try to look up info online, people keep saying that the Keihin CV carbs are a PITA to run on pods, and that getting these bikes to run properly across the rev range without factory airbox is nearly impossible.
Any advice/insights on getting a proper setup?
+akumabito2008 There is an element of truth in what you hear. These are Mikuni, not Keihin, but CV carbs are problematic on PODs. PODs don't deliver the air in a way that the carbs like and they become fluttery. The shared airbox gets rid of a lot of pulsing and they deliver the air through velocity stacks, which smooth's out the air delivery. My advice would be to fit your pods to the end of your factory velocity stacks. If you don't like that look you can fashion a restrictor to fit inside the POD, out of a Coke Can or similar, that will act as a type of velocity stack and restrict the air flow at the same time. I have heard that this is quite successful. I never got to test the theory as my carbs were badly damaged internally and the pilot circuit was oversized and uncontrollable. I ended up fitting these th-cam.com/video/5eUnbVAp8hI/w-d-xo.html
+Andy's Motorcycle Obsessions Thanks for the quick reply!
the airbox and stacks on my bike need to go - I want to convert my bike into a replica of the one Classified Moto build for the TV show the Walking Dead (www.classifiedmoto.com/motorcycles/daryls-bike/)
I want to get as close as possible, while still being practical and rideable. The filters I end up using don't need to be 100% screen accurate, but the airbox needs to go to make space for the bag.
+akumabito2008 I just checked that bike out, wow!!!! I love it. Mate, they have done a very clever thing with the airbox on that. They have fabricated a low profile shared airbox. That would not be too hard too duplicate and it would definitely help the carbs cope with a smooth operation. You would need to fabricate the tubes into the carbs to be as long as possible and fit a custom made foam filter but definitely doable, I just wish I'd have thought of it.
There are loads of cool little details on that bike. It'll be a fun challenge to try and replicate as many as I can.
I'm looking into custom airboxes at the moment. They definitely seem like a better option than pods. I think they look better, too. Steel dragon is making some that look good: www.steeldragonperformance.com/air_boxes_7.html
Definitely considering the diy route as well..
+akumabito2008 Those single airboxes are the Duck's guts mate, and cheap too. Unless you want to create something custom I would definitely buy one.
instead of pulling the plugs between each run, would you suggest getting a Gunson Colortune tool? and adjust the fuel mixture according to flame color?
G’day mate. Do you mean like this? th-cam.com/video/9mKQvWM0nMg/w-d-xo.html
@@ANDY5 yes exactly!!! awesome...now that only tunes the pilot circuit correct? will it have an affect on the main circuit during WOT or even 3/4 throttle?
The pilot circuit has an impact through the entire throttle range but the largest influence at 3/4 and WOT are the needle and main
Pls explain, if this pod type of carburetor fitted outside of a motorcycle frame without any cover ,can it ride on a rainy day ? will the water comes into the engine through the filter ?Thank you.
Yes it will allow water through. If you buy a reputable brand, such as K&N, you can purchase rain socks for them.
great stuff
Brilliant
Hi Andy, nice channel and great project. One question: where do you buy the jets to tune the carb? I only find the original sizes for my xs 1100.
G'day mate, thanks for the feedback. I use jetsrus.com
+Andy's Motorcycle Obsessions Thank you for the quick answer. Can you provide me the exact jets that you bought? I use the same POD Filters that you use and combined it to a 4-1 from marshall. the original setup, that can be found in the carb repair set is not usable and so i hope your setup runs better. Have a nice day - Stefan
I am using the standard pilot, 42.5 i think??? 147.5 on the main jet and needle lifted one position. Everything is new. New jets, new needles, new emulsion tubes and new diaphragms. It's not tested and tuned yet. I'll let you know how i get on. May need bigger Mains yet.
+Andy's Motorcycle Obsessions Thank you Andy, i will wait for your results. At the moment it is too cold to test my project and i have no dyno here. As you can hear in my videos, my bike runs very bad.
+Stefan Knierim Stefan your atmosphere will almost certainly be different to Tasmania so what works for me may not work for you. A couple of things to consider. 1. If you still have vent hoses connected to your carbs, remove them. I know it will open them up for debris ingress but I have been told they can have an impact. Leave the Tee's just remove the hoses. 2. Ensure that you have absolutely no vacuum leaks. 3. Make sure your valve clearances are set correctly. 4. Make sure you have good compression. 5. You can simulate the original air box conditions, sort of, by cutting some beer can aluminium and fitting it into the inside of the pod filters effectively restricting their intake and forming a kind of velocity stack to help smooth the air flow into the carbs. You want to cut a piece and wrap it around the inside of the filters blocking approximately 2/3 of the length of the filter, from the carb towards the front of the filter. Am I making sense? 6. Make sure your pods are not blocking the air jets on the carb intake, your pods look better than mine. Mate you have done a great job, she looks amazing. Try to find a local 'Old School' mechanic that can help. Good luck, keep us up to date.
Andy
If one of my four diaphragms has burst and requires replacement. Am I ok only replacing the burst one or do I need to replace all four diaphragms?
G’day Ross, you can replace just the damaged one mate. You can also try repairing it with a fuel safe silicone type sealant
Great video. Been wondering about the pods process myself. Are you an engineer?
+Q In a former life
So are all jets universal or do I need a certain type for my cb250rs project.
You need specific jets, check out jetsrus online
In my yamaha xj 600 90- it had 105 jets, but i installed pods and chopped the exhaust and installed better flowing mufflers, i played whit the jets for a while and the best air fuel mixture was achieved whit 115 jets..... idle is much ruffer now because i didnt know i should change the idle jet..... power band is now weird too but pulls from the top end really good. So what idle jets i should try first in your opinion. Also winter is coming to finland soon so im going to pull the engine out and change the cam chain and anything else if needed, im thinking should i polish the combustion chamber ? is there any good doing that on cinda stock bike......Sorry for any typos
+TT GarageRat G'day mate. 115 is about four jets bigger than 105's I think. Generally speaking you should increase your pilot jet by one size for every three on the main jet. So you should probably try one size bigger than what you have now. Jump on the Jets R Us website jetsrus.com/index.html and have a look. Pretty sure your bike has a Mikuni BDS26 carb so look for the BDS series on their web site. Good luck, let us know how you get on. Andy
+TT GarageRat Sorry mate I didn't comment on your question about the combustion chamber. Yes it is worth doing. The best approach is to get hold of a second hand set of valves and a clear piece of poly carbonate plastic, or similar, that is big enough to cover one chamber. Remove your good valves, be sure to mark where they came from. The function of the old second hand valves is to protect the seats when you are in there with a die grinder. Wipe some grease around the valve seats and insert the used 2nd hand valves, just put them in the valve guide and don't worry about fitting the springs or collets, and screw in a spark plug. Next take your piece of plastic and drill two 3mm holes in the centre, side by side. Turn the head, chamber side up, and level it. Wipe some grease around the outside edge of the chamber and place the plastic over the chamber. Then use a syringe to inject water, add a bit of food dye for colour, and measure the volume of each chamber. Find the one with the most volume and polish it first, known as "padding the chamber." Then work on each chamber until it holds the same volume as the first. This is called "CCing the chambers." The polish helps reduce carbon build up and aids air flow and matching the CC's (Cubic Centimeters) is one stage of "Blueprinting" an engine and ensures that you have continuity across all chambers. Be aware of removing too much material from the largest chamber as you will start impacting the compression ratio. I hope that makes sense???? Good luck.
+Andy's Motorcycle Obsessions P.S. you only need enough 2nd hand valves to work on one chamber at a time. Just move them from chamber to chamber. It's a good days work to do this job.
+Andy's Motorcycle Obsessions Sorry to keep adding but I forgot to mention that you should lay your head gasket over and mark the head with a permanent marker so that you don't grind, polish in the area it needs to seal. Right!!! That's it...I hope :)
Thanks! I got it :) I have seen some peole polishing the heads whitout the valves as an protect but better be sure.
has anyone tried these changes to the carb and if so did it work🤔
I find this very interesting. I know vitually nothing about this topic but you do a good job of explaining this to numbskulls like me.
What watch are you wearing?
That's an odd question mate. It's a Tissot Chronograph
I know. I'm into watches, especially divers.
BTW, nice watch
I wish you were my dad 🤓