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Discussion Starter · #1 ·
I am planning to swap out my K&N style pods that came with my ARK for some UNI pods. Based on what I've read on here the Uni's flow significantly better.

My question is do they flow that much better that I'll need to rejet?

Re-jetting is not an issue, but would like to buy the jets so I have everything at the same time I do the filters... I am running stock carbs, and Arrow 2-1 w/o the baffle.

Thanks!
 

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with stock carbs I dont think you will need to change jets from what the k&ns need.The uni filters do flow more air but stock carbs might not need more air then the k&ns can flow.You need the extra flow of the uni filters when you go to 39mm or 42mm carbs.
 

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Discussion Starter · #3 ·
with stock carbs I dont think you will need to change jets from what the k&ns need.The uni filters do flow more air but stock carbs might not need more air then the k&ns can flow.You need the extra flow of the uni filters when you go to 39mm or 42mm carbs.
Thanks!
 

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Mike i would think that the only way to see is to check every bike if a bike calls for more air then the k&n can give it then you would need to put a bigger jet with the uni filter but I dont think most bikes do.I think your bike must flow better then most stock bikes looking at the hp numbers you are getting.
 

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Does this mean I would have to re-jet if going from stock to K&N filter?
 

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But if one filter flows more air than another filter, you will more than likely have to jet up. This has always been the same on all the bike's I've worked on.
not if the filter that flows less still flows more air then the carbs or head can.I had the 42mm carbs on a stock 790 with the k&n pods it took 160 mains .when i did the head work and big bore with the uni filters it took 145 mains.and no mater what jets you put in it with the k&ns it would run rich because the filters would not flow enough to keep up with it.
 

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Sorry Mike I beg to differ. When carrying out filter testing, I had to move up a jet size when moving from K&N's to Uni's.
Weren't you using double layer Unis? I suspect that would make a huge difference.

I just switched from large K&Ns cones to 6" Uni socks and they definitely flow more at high RPM.
 

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uni filter upgrade on 07 Bonnie

I just replaced my TPUSA K&N style cone filters with 4" double layer UNI's. I was coughing at idle and low speed (1500 rpm) in my neighborhood test run but after taking it out and winding it up it seemed better. Do these filters need an initial "clearing out" or will I likely see this problem again? Throttle response is good and WOT seems killer. I had to adjust my idle up about 100 rpm for the new filters after fully warmed to get it back to 1100 rpm.

Thanks,
-pb
 

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When my CV carb 865/270 went from K&N pods to UNI4229 pods the upper WOT AFR went approx. 1/2 step leaner.
 

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Mike, thanks! That makes sense plus they will fit in there much better. I think I'll stay with my current jetting right now (140/40) so I won't start playing f-around again!
 
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