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Discussion Starter #1
First off I'm a new rider so my concern is reliability and longevity and not power enhancement. I drilled out the stock pipes and everything seems to be working fine as best as I can tell . No hesitation or popping. I had planned to just leave the EFI alone since I had read that this mod did not require any re-calibration. Then, on a recent trip to the Harley dealer I picked up a Twin Power EFI calibrator that was on clearance table for $40..couldn't help myself.LOL. So, my question is... since these bikes are known for running lean to begin with, should I richen up the mix a bit say 5-10%...will this be a good thing for motor? Or, should I leave well enough alone and save the calibrator for a later date if I should decide to install a louder exhaust.

Thanks in advance for your input.
 

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By drilling holes in your slip-on's you have altered the A/F ratio. These bikes come very lean from the factory. Your changes could put it over the edge and burn up an engine. Best to settle on the pipes you will ultimately need, install them then have the bike dyno'ed by someone that knows what they are doing. If you guess wrong you buy a new $6500 engine or a costly repair bill.
Don't count on everything you see or hear on this or any forum to be gospel. Lots of shade tree mechanics here.
 

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When changing pipes best to install a high flow air filter also. Lots more in lots more out.
 

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When changing pipes best to install a high flow air filter also. Lots more in lots more out.
If by high flow filter you mean K&N, I'd disagree. K&N is a good product for a specific purpose, that purpose isn't filtering out fine particulate.
 

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Pat (Patrick!)
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I drilled out the stock pipes
Did you v-mod(big hole!) the pipes, or drill eight 1/2" holes in the ends?
 

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Did you v-mod(big hole!) the pipes, or drill eight 1/2" holes in the ends?
I've seen several people claim you don't need a any fuel management if you drill the 8 .5" holes, and that it's necessary if you drill out the baffle. But drilling out the baffle is the same area as 9 .5" holes. Does that extra .19 square inches really make the difference?
 

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Discussion Starter #7
I've seen several people claim you don't need a any fuel management if you drill the 8 .5" holes, and that it's necessary if you drill out the baffle. But drilling out the baffle is the same area as 9 .5" holes. Does that extra .19 square inches really make the difference?
I just drilled 8 5/16 inch holes, the baffles are intact. When you drill out the baffles (V-Mod) you remove the guts leaving a hollow pipe. Allot more airflow through the V-modded pipes. Still, I am wondering if it would be wise to enriching the fuel mixture a bit.
 

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Pat (Patrick!)
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I've seen several people claim you don't need a any fuel management if you drill the 8 .5" holes, and that it's necessary if you drill out the baffle. But drilling out the baffle is the same area as 9 .5" holes. Does that extra .19 square inches really make the difference?
VMOD removes the baffle. Drilling does not.
 

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VMOD removes the baffle. Drilling does not.
Where does that leave us? A hole in the can is a hole in the can. From a volume standpoint, the same amount (or near enough as not to matter) of gas is going to escape. I could see there being a difference if the holes were inside the baffle, but they're not.
 

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Where does that leave us? A hole in the can is a hole in the can. From a volume standpoint, the same amount (or near enough as not to matter) of gas is going to escape. I could see there being a difference if the holes were inside the baffle, but they're not.
Judging by the huge difference in the sound volume (baffles removed being much louder) I would imagine the volume of gas is also greater.
 

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Pat (Patrick!)
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Where does that leave us? A hole in the can is a hole in the can. From a volume standpoint, the same amount (or near enough as not to matter) of gas is going to escape. I could see there being a difference if the holes were inside the baffle, but they're not.
With the baffle removed, you are removing a serious amount of back pressure.
 
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