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Good information on Pods vs Airbox

Discussion in 'XJ Technical Chat' started by sybe, May 22, 2017.

  1. Scott Tiplady

    Scott Tiplady New Member

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    Well I’ve been a Suzuki tech for 30 years and like any engine mod inc pods just takes patience and time to set up your fuel system properly. Yes a dyno helps but I’ve been lucky to get any used or new bike run well. Even if the dyno was not available.
    Just saying.
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    Clymer suggests going to slide carbs then pods to make performance increases.
    with CV carbs it is just a crap shoot just to remove an air box.
    I always wonder why most people think they are smarter than Yamaha engineers.
    I guess it is the telling someone it can not be done that sets up the challenge.

    The UK guy with the video even says he uses slides.

    if you are going to pod get good pods not the china pods
     
    Timbox and k-moe like this.
  3. KrS14

    KrS14 Active Member

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    Running pods means you had to rejet correct? In putting pods in my xj650 now and I was wondering were a good place to order jets from was

    Cafe_Guy94, Jul 11, 2017

    Just sayin.
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    yes you will have to rejet and rejet and rejet until you find the …. well until you are happy with the results.
     
  5. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Start a conversation with @chacal
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    a bunch of people on the xj facebook site claim to have the proper jetting but when you try to pin them down on how well the bike runs you find they are just putting down the road to the next "coffee"shop flat road riders .
    tried all summer to get satisfactory performance out of a podded 750. ran best on flat roads and in the cold weather. did not even come close to running like my other 750 which is stock. bike with pods 85 mph max slows down on the long up hills to the point of it being a danger due to traffic around me. stock 750 just keeps going faster up hill as I twist the throttle. my 550 would leave the pod mod behind.
    I have installed an air box in it and gone back to stock jetting when spring comes I know I will not be disappointed with that ugly airbox I am thinking of putting lights in my pods so I have the cool look of pods being used as blinkers.

    feel free to pod away
     
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  7. XJ550H

    XJ550H Well-Known Member Premium Member

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  8. KrS14

    KrS14 Active Member

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    You missed that one Moe, but completely understandable :)

    I was quoting for the necro by Scott Tiplady from 2017, but it didn't actually quote it properly :/ .
     
  9. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Here's something else to take under consideration: the original Yamaha carb-to-airbox boots are actually VELOCITY STACKS you just can't tell without close examination. They're not just rubber "bellows" they have a very carefully engineered inner profile.

    Years back, I sliced one in half longitudinally so the clever section profile would be easily visible. I'll dig around and see if I can find it and put up a pic.

    In theory, 'pods' mounted on Yamaha carb-to-airbox boots would probably work a lot better...
     
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  10. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    There was a lot of discussion about that while you were on vacation. Several members have used the intake boots in conjunction with pods and gotten very acceptable results.
     
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  11. BasketcaseBiker

    BasketcaseBiker Member

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    Whenever I bought my xs750 it didn't have an airbox with it. So I made one I built a ram air box and I had other fueling issues I didn't realize and it was complicating everything making it almost impossible to tune enough to drive. So I wound up using open carburetors and open individual pipes. No velocity stacks, no pods, no y pipes on the exhaust, and I was chasing my till until I solved some fueling issues relating to pinholes in one of my brass floats and a leaky auto petcock. Once I solved those issues tuning was very easy. Everyone said that it was impossible to tune the bike for open carbs and Open exhaust. It is not impossible. The bike pulled so hard that it wanted to come up and it was an airhead 3 cylinder 750. I ran it that way until I sold it. Never had any problems. No I've got this xj700x and it came with no air box and with pods that were crushed against the frame and too small for the carburetors that were attached with rubber tubes. I wish I had the factory velocity stacks to use but I guess I will make them out of the rubber tubes using my Dremel. I've been forced to run open carbs twice now. And since that's the case then I'm going to put velocity stacks on it, and remove the baffles, because if I already have to rejet probably then why not?,I have a rivet gun if I change my mind and want to reinstall them. What I found when I was tuning the xs750, which had been bored to 828 btw, was that the factory needle clip position was the position that clip needed to be in. And that I didn't have to go up very much for optimal performance. And that the factory pilot Jets were fine, and I had them set very close to factory settings. Also I don't know if the bs34s are supposed to have the rubber plugs in the bottom of the pilot Jets but mine did not have those and it ran great. I could start it with one kick almost every time regardless of the temperature. And if it wouldn't start with one kick it would start with two. It all comes down to tuning. No I didn't just throw a couple jets in there and it magically worked, I spent a lot of time with trial and error. I would try something and ride the bike and over the course of a few months thinking maybe it needs to be a little leaner maybe it needs to be a little richer, and one day I found the sweet spot. So you don't necessarily need a Dyno but it'll take a lot longer if you don't have one. It's always the tune and not the parts, unless something is broken, leaking, or way out of spec. Also when tuning keep in mind that especially on an airhead that you want the middle cylinders whether there's one or two doesn't matter the cylinders in the middle of the engine need to be jetted richer than the cylinders on the outside so if it's a three cylinder then number two needs to be one jet size more so if the carburetor is jetted 125 on 1 & 3 then it needs to be jetted 127.5 on cylinder 2
     
    Last edited: Mar 23, 2025
  12. BasketcaseBiker

    BasketcaseBiker Member

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    Really any intake system you want to invent will work just fine, but the reason why people wind up chasing their tails it's called "Lost in the carbs" it's what the old heads used to call it, it's because whenever you're flowing more air, whenever the engine is sucking harder it's actually causing more fuel to be pulled through the main jet anyway... And if I remember correctly what I wound up doing , "The Sweet Spot" was a 130 jet in the middle, and 127.5 on either side. So I really only went up one jet size. The only scenario where you would have to dramatically increase the jet size is one where you've reduced intake velocity but increased airflow. This sounds contradictory but it's not, you can put huge valves in a head and Port the crap out of it and wind up with this exact situation that actually usually reduces horsepower unless you're using a power adder like nitrous oxide or a turbo. And this is exactly why fuel injection engines can usually compensate for even extreme intake and exhaust mods as long as it's within naturally aspirated limits, without changing fuel injectors. Again, The increased suction through the jet will increase the amount of fuel present during combustion.
     

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