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Discussion Starter #1
i changed my cb750k from podsback to a stock airbox with a uni filter in it and it's sounds like it's running lean as hell at full throttle now, and it didnt before with the cheap emgo pods. i have a 122.5 main jet, the stock air jet and the jet needle in the middle postiion. timed at stock specs with a dyna-s and 3 ohm dyna coils. anyone here have the same thing happen?

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Maybe this will help. A quick check I like when I think the main jet is lean is a roll-off test. I like it because it is quicker than doing plug chops and you don't have to sit at the side of the road pulling plugs.

At a comfortable speed, say 60mph, accelerate at WOT (wide open throttle) to 75 or 80 mph (the higher the better) and smoothly roll off the throttle to 7/8ths or a little less. Pay close attention to the bike and the rate of acceleration.

Bike wants to increase rate of accelleration = Main jet is lean and you need to increase main jet size

Bike wants to maintain accelleration, or feels like you have done nothing different when backing off = Your main is right on the cusp, slightly lean.

Bike looses some momentum, but is still accerating, just at a slower rate. Then the main is not lean

I wouldn't depend on what it "sounds" like unless you already know what to expect on that particular bike. For example, my Triumph is spot on or a hair lean near home (800ft) and it has a higher pitch than it does with the same jetting when I am at elevation (4000ft). At 4,000ft, the sound is more dull, but I already know I am running a bit rich, so I recognize the difference.
On the other hand, my GS750 makes no perceivable difference whether running lean or not.

Bikes: 05 Triumph & 77 GS750
 

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Discussion Starter #3
ended up being REALLY rich. i thought i had 122.5 mains, ended up being 127.5's with the plug chop testing i got it to a 110 and all is well, bike runs even better full throttle than it did with pods.


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