View Full Version : Intake, Exhaust and the mix on 2007s - Question

16th March 2007, 06:36
Ok, so here's the deal...

Picked up my new Nightster a couple weeks ago and now have 250 or so miles on it. Before I took delivery I had the dealer do the SE slip-ons and A/C. No adjustments were made to the computer.

This is my first Harley, so I don't REALLY know what to expect in terms of performance, feel, etc. What I would say is that I kind of feel like engine gets a little shaky at low RPMs and also that the throttle doesn't feel *as* crisp as I guess I would expect.

First, I haven't really cracked it open much since it's still in break-in mode (maybe I'm babying it a bit too much - although I don't think so) and second, maybe it's just a symptom of an un-broken in engine. It's not BAD, but it just isn't knocking me out.

I've read that when you switch both the exhaust and the A/C a download is almost always necessary. At this point I really think that I'd like to go with something like the "Heavy Breather" or Forcewinder. I'll probably do that after the break-in but obviously will probably want to do something about the computer at the same time.

A few questions...

1) Does it sound like the symptoms I described are probably resultant from the computer needing to be adjusted?

2) My dealer has recommended looking into the SERT at some point in the future? Is that my best bet when the time comes to make the adjustment or should I be considering something else?

Thanks a lot. Loving the bike so far but I really think with some tuning I could get a better experience.

16th March 2007, 07:54

I'm not an expert, by any means. But having gone through stage one myself, I can tell you that you should feel a significant improvement in power over stock. Perhaps part of the reason you aren't "knocked out" by your bike's performance is that you haven't had your bike's fuel air mixture adjusted in order to compensate for the increased flow of oxygen through its exhaust/intake system. I would suspect that your engine is running lean, which (as I have gathered from threads about the issue on this site) both hurts performance and puts undue stress on the engine itself.

Therefore, I think your dealer was remiss if he didn't give your bike a remap when he installed the pipes and new aircleaner. I don't think you need the SERT unless you plan on doing a lot of engine modifications in the future or are a fanatic about precise tuning (I'm one, so I'm getting a dyno-tune on my SERT-equiped bike next week!). A remap costs about one-third of a SERT.

Also, 2-into-1 pipes make a few horsepower more, as I understand it.

Good luck!

Zepfan (= Led ZEPpelin FANatic)

16th March 2007, 08:47
PS. I think that just about every HD dealership has test-drive Sportsters. Since you don't know much about what you should expect from your new Nightster, performance-wise, riding one will enable you to make a reasonable comparison. Next, test drive a big-twin, it doesn't matter if its an 88-incher or an '07 96-incher. You will be very grateful for your Sporty's performance after the experience.

Now, of course, if you just stepped off of a high-performance European or Japanese sportbike, the Sportster will seem to be somewhat of a let-down, in terms of absolute handling ability and horsepower. Yet the Sporty delivers a "feel" of excitement and power that is completely different in quality from a UJM. It's like comparing a souped-up 50's or 60's muscle car to a modern Ferrari or Porshe. Both are nice, in their own way, but they are both very different. You don't have to work to obtain the power you actually need on the road while riding a Sportster. It never seems "busy". It always feels relaxed and cool, even when its smoking a mustang, camaro, or corvette.

It also looks da*n good (!) while doing so!

Stage one produces decent power, for everyday use, as far as I'm concerned.
However, if you're willing to spend the bucks, the potential of the Sportster engine to produce additional power is legendary. There's always stage 2 (cams, headwork, etc.) and stage 3 (88" bore-kits, stroker-kits, nitrous, etc.). Harley-Davidson used the basic Sportster engine on its flat trackers for decades and Evel Knievel rode his Sportsters to glory!

Any more questions?

Zepfan (= Led ZEPpelin FANatic)

16th March 2007, 08:58
Ok, so here's the deal...

Before I took delivery I had the dealer do the SE slip-ons and A/C. No adjustments were made to the computer.

First, I haven't really cracked it open much since it's still in break-in mode (maybe I'm babying it a bit too much - although I don't think so) a

If you didn't ride it before the mods it is hard to say what it felt like before. I would think that the computer would need to be adjusted but I haven't seen any info from Harley regarding this.

If you haven't ridden a Sportster before I would bet that you are probably babying it. Rubber-mount or not, they still shake more than an inline 4. Get on it a few times, the engine during breakin should really be babied. A good mix of different RPM ranges will seat everything better than treating it like an antique vase.


16th March 2007, 09:19
I agree that the dealer should definitely do a remap. You could also be babying it to much. Check the owners manual on the correct breakin procedure. I believe it says in there something about not to lugging it too much. If you're used to having a tach that may be part of your problem it's hard to say how low of rpm you're running it at. I can duplicate the shaky rpm's simply by being in to high of a gear for the current speed.


Don Burton
16th March 2007, 11:05
If you're babying it, the rings will never seat. It needs some intermittent WOT runs with cool offs in between. WOT to about 4000-4500 (not 6,000) rpm then shift to the next gear up to about 70 mph or so then let it back off. Do that intermittently and frequently for the first 50 miles and your rings are seated. Vary your speed and give it some gas occasionally, Do not baby it, beat on it or overheat it as that's no way to break in anything. I think they've already covered the fuel air mixture fairly well.

Screw Loose Dan
16th March 2007, 13:18
I find it hard to believe that the dealer would actually deliver the bike without doing the remap. All the dealers I've spoken to about about it (at least three that I'm thinking of) INSIST that it must be done. Some will even reference the HD Accessory book (it clearly states that the SE AC requires a remap).

That being said, more then one of us (http://www.xlforum.net/vbportal/forums/showthread.php?t=41426) have put on high flow A/C's and exhaust without issue. It's really up to you if you think it needs a remap, then go pay the dealer to do it. There's no doubt if it wasn't done, you will notice an increase in performance by having it done.

The SERT is a great tool if you want to spend some $$ on tuning the bike. The module will likely be the cheap part at $350-$400. The SERT comes with canned maps that can be used and tweaked, but to really get the most out of it 4-6 hours worth of dyno time are required to tune everything right. And if you make a change, you'll have to spend more time and money tweaking. Most guys probably aren't going to have the dyno shop spend that much time tuning it, but they won't get everything they can out of it. It is a really good tool, but probably more then most will need.

I also agree with Zepfan that this is all subjective. Are you stepping off a crotch rocket and expecting the Sporty to be like that?

Also, don't worry about the low RPM shakes. You don't have enough miles on the engine yet to be lugging the motor. Seriously, don't damage your motor by lugging it when it's brand new!

16th March 2007, 14:14
I have an idea (but not a particularly good one!), of what "lugging" is? Can someone please outline what it means, because I pick up my '07 883 Custom next month, and it sounds like I definitely don't want to be "lugging".Cheers.

Moved On / My Own Choice
16th March 2007, 15:24
I have an idea (but not a particularly good one!), of what "lugging" is? Can someone please outline what it means, because I pick up my '07 883 Custom next month, and it sounds like I definitely don't want to be "lugging".Cheers.

Lugging is attempting to accelerate a motor under load in too high a gear or too low an rpm.

When pulling away from a dead stop it means not giving it enough throttle and not getting the revs up enough before starting to engage the clutch.

When rolling down the road it means simply being in too high a gear and trying to accelerate from too low an rpm (below 2k on a Harley, though I tend to like to keep em at or above 3k myself).

When lugging a motor will feel sluggish and may buck or shudder a bit.


16th March 2007, 16:04
Thanks for the input! I think I may finish my first 500 miles or so and then see about getting some tuning done.

16th March 2007, 16:15
WOW, I was told before I even purchased the bike... slip ons ok, A/C without remap not ok and I would void my warranty. They should know you are hurtin your engine a bit. get that thing flashed

16th March 2007, 17:29
Yesterday I picked my bike up from my indy - had first 1000 mile service done as well as NRHS Hurricane flow AC and SE II 49 state legal slip-ons installed. Rode 200 miles and all I can say is WOW, the difference is amazing. We didn't do anything to the efi but he is a wiz with the throttle. It rolls on very smoothly with no dead spots. The bike is so much quicker it is like a different bike. I have a tach and like it very much. I certainly can hear and feel when to shift but when it's at the top or bottom of optimal rpm range the tach tells the true story. And with the bike running so smoothly it changed my perception. This is my second bike but first Sportster altho hubby has an '06 883R, which I've ridden a lot and they are so different, both fun.

Also had some geometry issues fixed i.e. seat and rizer mod that improved handling and my comfort.

Oh and the mileage went from 48 +/- mph to 50+.

17th March 2007, 00:45
I'd ride a demo. Mine's a shaker under 2500 rpm - nature of the beast, I think. The power is very smooth and tractable. I'm banned from accessories for a while, but plan to get more power in a year or so via that route. What I mean by tractable is that a novice could ride my bike if it weren't so heavy. Congrats on your Nightster... fine-looking bike!