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Discussion Starter · #1 ·
2 different tuners (Tab and now a PCV) and a proper dyno-tune later and my F is still choppy at 4-5k. If I hold it at 4500 on a smooth, straight highway, it chugs, not violently but its def noticeable.

What do i look for next? I'm not real mechanical, a little but not enough to actually diagnose what it could be. Could it be something in the throttle body/intake?

Bike is a 2009 F, open top, Tab slip-ons with no engine mods.
 

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2 different tuners (Tab and now a PCV) and a proper dyno-tune later and my F is still choppy at 4-5k. If I hold it at 4500 on a smooth, straight highway, it chugs, not violently but its def noticeable.

What do i look for next? I'm not real mechanical, a little but not enough to actually diagnose what it could be. Could it be something in the throttle body/intake?

Bike is a 2009 F, open top, Tab slip-ons with no engine mods.
Your issue is fueling. Sorry but to be rough at 4-5k the tune is pretty bad. That area is out of heavy reversion and quite stable for O2 sensor reading for good data. Even the DIY guys nail that area without difficulty. Typical hard spot to tune is 2500-3500 and that requires extra effort. You need to revisit the tuner and bitch more.
Currently , I can only view PV tunes to identify problem areas, so not much help. My suspicions are this 4-5k area is too rich. 25-3500 are often lean due to EGR effecting correct fueling.
Ron
 

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Discussion Starter · #4 ·
I don't think its the map/dyno because when I got it (used) it was set up with a stock air cleaner, non-open top and only slip-ons and it had the same issue. I tried the tuners to alleviate that issue.
 

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I don't think its the map/dyno because when I got it (used) it was set up with a stock air cleaner, non-open top and only slip-ons and it had the same issue. I tried the tuners to alleviate that issue.
If you can go wfo and it will pull all the way up without missing, it eliminates ignition and fuel pressure as possible causes. Will the bike do this? Got any codes related to either front or rear cyl misfires? I still suspect the tune but let's rule out any other possibles first. What was the tuners excuse and why did he give it back to you in this state?
Ron
 

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The Massive Pr1ck
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This is a common issue with a poor tune. When you say proper dyno tune, what exactly do you mean? E.g. My dyno tune took about six hours and 3/4 tank of gas and was done on a load cell dyno. Over a hundred pulls in all.
 

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I know you don't believe so, but it is the tune. When you say you "tried two different tuners" do you mean you've installed two separate tuners, or you've had it to two different dyno guys? I'm guessing the former. If the latter, take it back. Like rbabos said, that area is very stable, its the lower range that sucks to get running smoothly.

Also, define "chugs". Is there are really noticeable drop in performance of the motor or does it just sort of stutter a bit without impacting speed or power? A true "chug" is not the kind of thing we usually see with tuners but a momentary blip in the engine not lasting longer than an eyeblink, thats what we typically have issues with regarding our engine tunes on the vrod, and usually in a lower rpm range. My bike runs smooth as silk after 4K, but prior to that will do the stutter thing. Its is more annoying than performance degrading, and with a WOT none of this occurs.

As one other poster said, if you can WOT through this range without any "chug", its in the tune, my friend.
 
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