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[FlaHeatWave]

Just had the SE Stage III Pro Kit (SE 259e cams, 10.5/1 pistons, SERT, Dyno Tune) installed in the '09 SERG, that already had Ventilator/K&N, V&H PowerDuals, Roland Sands Design Tracker Slip-Ons.

Put a little over 600mi break-in, then on the dyno for the 'final tune' (98/107).

Went to pick up the bike and the Tech that has done all the work on all my HDs for over 10 years, tells me of the flat spot around 3k rpm, said that he tried everything that he knows with the SERT and thinks that it's the pipes.

The Tech was right, the bike runs great everywhere except around 3k rpm where it has a flat spot that you could park a truck in.

On a 2600mi ride to KY, IN, TN, NC, last week the bike got 40-41mpg except mid to low 30s really flying on the interstate.

Does anybody know what is causing that flat spot and how to get rid of it ?   

[Fired00d]

Just had the SE Stage III Pro Kit (SE 259e cams, 10.5/1 pistons, SERT, Dyno Tune) installed in the '09 SERG, that already had Ventilator/K&N, V&H PowerDuals, Roland Sands Design Tracker Slip-Ons.

Put a little over 600mi break-in, then on the dyno for the 'final tune' (98/107).

Went to pick up the bike and the Tech that has done all the work on all my HDs for over 10 years, tells me of the flat spot around 3k rpm, said that he tried everything that he knows with the SERT and thinks that it's the pipes.

The Tech was right, the bike runs great everywhere except around 3k rpm where it has a flat spot that you could park a truck in.

On a 2600mi ride to KY, IN, TN, NC, last week the bike got 40-41mpg except mid to low 30s really flying on the interstate.

Does anybody know what is causing that flat spot and how to get rid of it ?   

Why not trust the guy (tech) that has been doing the work on your bike(s) for the last 10 years... evidently you trust his work/knowledge. Did he recommend another pipe?

 
Ride Safe,
Fired00d
 

[grc]

I believe more in the "trust but verify" mindset, versus just assuming because a guy has wrenched on my stuff for ten years that he automatically knows everything there is to know.  So I think FlaHeatWave is smart to seek other opinions before throwing a bunch of cash at a new exhaust system which may not be the problem at all. 

If I understand the situation, the bike had this exhaust system on it before the latest cam and compression change.  So my first question would be, did you have that same huge hole in the curve before the latest work, or did it only show up after the latest modifications?  If you have a previous dyno chart to compare to the latest one, that comparison may give you some clues.  In the meantime, why not post your latest dyno chart here so the tuning experts can see exactly what you're talking about?

Jerry

[Fired00d]

I believe more in the "trust but verify" mindset, versus just assuming because a guy has wrenched on my stuff for ten years that he automatically knows everything there is to know.  So I think FlaHeatWave is smart to seek other opinions before throwing a bunch of cash at a new exhaust system which may not be the problem at all. 

If I understand the situation, the bike had this exhaust system on it before the latest cam and compression change.  So my first question would be, did you have that same huge hole in the curve before the latest work, or did it only show up after the latest modifications?  If you have a previous dyno chart to compare to the latest one, that comparison may give you some clues.  In the meantime, why not post your latest dyno chart here so the tuning experts can see exactly what you're talking about?

Jerry

Jerry to a certain degree I can agree w/what you're saying.. however after 10 years the "trust but verify" should be well established. However seeking opinions on the internet w/out providing all or limited information can result in as many opinions as an oil thread.

 
Ride Safe,
Fired00d
 

[FlaHeatWave]

Why not trust the guy (tech) that has been doing the work on your bike(s) for the last 10 years... evidently you trust his work/knowledge. Did he recommend another pipe?

 
Ride Safe,
Fired00d
 

He recommended Rineheart true duals

[spydglide]

I have Reinhart True Duals and had the flat spot also.  I can be 'tuned out', mine was after changing to the HD Race Tuner.  spyder

[grc]

He recommended Rineheart true duals

There's nothing special about those either, and plenty of folks have had dips in the torque curve with those as well.

How about my earlier question, did you have this flat spot or dip at 3k with the same exhaust system before he changed the cams and pistons? 

Jerry

[FlaHeatWave]

I believe more in the "trust but verify" mindset, versus just assuming because a guy has wrenched on my stuff for ten years that he automatically knows everything there is to know.  So I think FlaHeatWave is smart to seek other opinions before throwing a bunch of cash at a new exhaust system which may not be the problem at all. 

If I understand the situation, the bike had this exhaust system on it before the latest cam and compression change.  So my first question would be, did you have that same huge hole in the curve before the latest work, or did it only show up after the latest modifications?  If you have a previous dyno chart to compare to the latest one, that comparison may give you some clues.  In the meantime, why not post your latest dyno chart here so the tuning experts can see exactly what you're talking about?

Jerry

Thank you, Jerry.
I am of the "trust, but verify" school of thought.
I do trust my Tech, but asked here because of the hundreds of years of real world experience that the members / posters here have to offer / share.

The '09 had the V&H PowerDuals / RSD Slip-0ns, V&H FuelPak, Ventilator on it when I got it 6/12 and ran perfectly (no flat spots, anything) until the stock 255s fell off around 4k (which is normal for 255s in a stock 110 motor).

The bike never had a "before dyno run".

The flat spot only came on with the installation of the 259e cams, 10.5/1 pistons & SERT.

My Tech did recommend the Rineheart True Duals (which I am not a big fan of ~ there has to be other options out there). I haven't heard of any similar complaints about the V&H PowerDuals (the PowerDuals seem to be fairly popular) ~ The RSD Slip-Ons might be part of the story ~ they are expensive ($725) and I don't know of anybody else running them to get any feedback from.

'Guess I will have to get over my phobia of limited computer knowledge and learn how to post pics on these forums.

I appreciate all the help that I can get.

[Beak Boater]

My 2010 SEUC had Rineharts, Stage 1, and SERT, all were dealer installed. Had a cough at 2200 rpms, not a backfire just a cough through the throttle body. Go above or below it was fine. Dealer tried and tried to tune it on the dyno, told me something about couldn't tune below 10% throttle. I didn't know it was my first experience with this stuff.
Finally, the dealer took off the SERT and put a Power Commander V on it. It ran great and no problems. Now this is a Harley Dealer on a new bike. Now after talking to many folks on this board and in person at dealerships I found out that it was BS, their tech just couldn't tune a SERT.
After 13000 miles the bike still runs great, I just never use that dealership for anything else. I trusted them too.

[FlaHeatWave]

My original post was not intended to bash or second guess My Dealer, as they have always been very good to me over the years, and have always bent over backwards to make it right. Everybody at my Dealer takes pride in their craft.

I'm sure that my Tech at my Dealer doesn't do anywhere near as much tuning as the "dedicated tuners" that are out there.

We all know there is some art to the science of tuning!

I was hoping that some of the gurus on this forum would give some insight to head us in the right direction (to get rid of the flat spot around 3k rpm) on my '09 SERG , SE Stage III, V&H PowerDuals, RSD slip-ons!

'Just went on a road trip with a good friend of mine (he averages over 30k mi. / yr ) with a Skunk that he just sank about $6+K in his motor, not counting the DD7 (welded crank, Carrillo rods, cams, bored to 113, head work, exhaust, the kitchen sink etc...) His motor was built and tuned by an Indy (2 states away) that has a very strong reputation for building / tuning. The 113 Skunk has the same flat spot (around 3k) as my '09, except that is not quite as pronounced, I think that the extra cubes / DD7 is smoothing it over somewhat.

As I originally posted, I just want some positive input on how to get rid of the flat spot in my '09 SERG w/ SE Stage III, V&H PowerDuals, RSD slip-ons