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Custom Air box

Discussion in 'XJ Modifications' started by paul.hardy, Aug 30, 2013.

  1. paul.hardy

    paul.hardy Member

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    Hi Guys. Here is some picks of an air box I made out of 50mm PVC pipe.foolishly I cut my original one up as I was going to run PODS. I could not get it to run right with PODS so I came up with this idea. I used epoxy glue but some say this it not the best for PVC but it seemed to work ok for me. You can find free programs on the web that will print out templates so you can make the saddle joints, There is enough flex in the pipe to clamp it tight on the carb with a good hose clamp.I have had it on now for about six months and the bike runs as good as it did with the original box. As this was hidden behind the side covers I did not spend to much time making it pretty but I recon if you wanted to spend the time you could make it so it looks good on a CR or Bobber. anyway it might help someone who like me ignored the advice on this site about POD !
     

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  2. Fuller56

    Fuller56 Well-Known Member

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    Very interesting. Do you get a lot of, or any, intake roar? A lot of air box design goes into eliminating that. Or is that drowned out by the exhaust roar from the 4 into 1? Any performance issues as another big air box issue is volume.... at least on the new, fuel injected, have to be the fastest sort of bikes. If it works well for you... Great!
     
  3. paul.hardy

    paul.hardy Member

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    Hi Fuller56. I have not noticed any induction noise and the 4 into 1 is not that noisy, not having ridden a standard well tuned XJ to reference its performance against its hard to tell how the bike performs against a standard bike. It starts well runs smooth and accelerates smooth and strong. I would say it feels like its sort of flattening off in power/torque a bit around 5000 5500 RPM but it did that before the air box change. It could be the 4 into 1(not fitted by me) not sure if the PO ever re jetted, but as at those revs the bike is way over the speed limit it is not really an issue all that often. As the bike is running well I am reluctant to get into the carbs to look at the jetting maybe one day. As much as I understand it these bikes are very sensitive to different air pressures at the venturies that's why PODS are not that successful so I suspect the air box plays a big roll in evening out the pressures across the carbs as well as the other stuff you mention.
     
  4. lacucaracha

    lacucaracha Member

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    6000 is when the fun starts. Try taking it over 6000 once or twice. Also check your plugs, or better yet color tune to make sure the offset on that intake isn't causing an issue on one or more cylinders...After syncing all of the carbs/valves etc...
     
  5. paul.hardy

    paul.hardy Member

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    Thank lacucaracha. Good advice I had spent a lot of time syncing the carbs, checking valves clearances and adjusting the mixture with the Color tune etc trying to get it to run with PODS. When I re fitted the air box and it improved things so much I did not even think to go back and check those things again.

    just found an excuse not to cut the lawns this weekend "sorry love" have to work on the bike :)
     
  6. jmilliken

    jmilliken Well-Known Member

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    yea... Paul, it seems that your bike is flattening out right when the fun should be starting..... these bikes show their personalities between 5k and redline.... I'm also curious as to how your plugs are
     

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