Bike feels like it has a flat spot until it gets past 3500ish rpms in first gear. Meaning, when taking off in first either aggressively or just normal riding and I keep the throttle in the SAME position, after 3500 rpms the bike pulls noticeably harder and kind of lunges.

Same flat/dead spot happens when cruising in any gear at low rpms (under 4000) when I crack the throttle a little bit and the bike takes a second or two and then takes off.

It really reminds me of turbo lag. Like it takes a second to build boost then it goes.

I have a 2011 and didnt really notice it that much with the stock exhaust. When i switched to slip ons and a 06 catless header i noticed it more. I guess I lost some low end tq.

My reading says pulling the flies on 08+ models wont have much effect but is this laggy feeling the result of the flies slowly opening up? If so ill get rid of them asap

* Last updated by: bentz69 on 5/13/2012 @ 4:57 AM *

had the same thing on mine a good map got rid of it on mine and I still have the flys in

^i just got a used pc5 and it has brocks street map (for the street meg/flies in) on it so im using that map for now. The bike runs great all over with this map except for what this issue. I plan on getting a custom map done and im debating on getting guhls flash as well. If i get the flash ill have them open the secondaries very early

My 2008 had a stumble at 3,000 rpm and after I put a good exhaust system and piggy on it with Brock's street map, the problem went away.

I don't see any stumble in my 2012 Concours 14. Granted, I don't see the horsepower either, but it is very linear and always predictable.

Going to see Don Guhl sometime this year, and get him to do a few dyno pulls and then re-flash her based on that, which will include a new secondary butterfly table to get them open early and keep them open based on throttle position etc.

My reading says pulling the flies on 08+ models wont have much effect but is this laggy feeling the result of the flies slowly opening up?

Yes

If so ill get rid of them asap

That is only half of the problem. You pull the flies and now you got air but on the stock mapping, you will still feel the hit (I always thought mine was at ~3500 rpm).

Here is the history of my flies in throttle response.

6,000 miles pulled flies. No real change i the zing at 3500. Maybe it was a little softer. NOt worth pulling the flies for all the good it does by itself.

11000 miles installed PC5 and loaded a map from Fuelmotousa. soft low end still there and abrupt poer delivery above 3500 still present. Perhaps a wee bit better but still hardly any change.

20,000 miles installed AutoTune and road the bike for one month. I then accepted trims and the problem was all but gone.

30,000 miles I can corner hard with complete confidence that a sudden burs of power will not happen.

seems like the only real answer is to have guhl flash it and re-map those flies to open up real low in the rpm range

thanks guys