Oh where to start? I just introduced myself here a couple days ago and mentioned I have an 01 1200S. I'm a little puzzled over my latest configuration.

Last summer the only mods I was running were a SE intake (w/ K&N filter), 45/180 jets, and straight drag pipes. I dyno'd 69.5hp and 74.5tq. I was pretty happy about it.

This winter I installed an SE ICM (6,800rpm), N4 cams, and SE Pro II slip ons. I dyno'd at 71.0hp and 67.5tq. I'm pretty bummed out.

1.5hp gain and 7lb loss in TQ?? So what, if anything, went wrong?

The dyno guy started telling me all about how I needed head work and increased compression.
(Sidebar: Do any of you Sport owners tell a dealer or wrench that you own a Sport and they look funny at you?? When he was filling out my paper work and asked what model, I said "1200 Sport". He said "custom or roadster?" I said, "Sport". Then he looked curious, and I said "It's a Sportster 1200 Sport". The light came on and he said OH! So this happens all the time...)
So since most guys don't seem familiar with the Sport, I didn't bother going into it with him. But that's because I'm not 100% sure about some things, either.

Correct me if I'm wrong, but doesn't the Sport already have a 10:1 something comp ratio, compared to every other models 9:whatever? And doesn't the Sport have improved heads over the other models stock heads? So I'm dismissing the need for head work and increased compression.

I'm no expert on reading dyno charts either, and I'm at work and don't have a scanner, but let me try to sum it up. Last summer first run: TQ curve started going up at 3.5rpm from 66ft/lbs, hit 70 at 3.75, and hit 73-74 at 4,000. It stayed there until 4.8, then gradually went down, falling below 70ft/lbs at 5.1rpm and revving out at ~67ftlbs/5.5rpm. Clear as mud?

This latest run: Started to climb from ~60ftlbs at 2.5rpm, climbed to 65ftlbs at 4.0rpm, and hit 67.5 at ~4.2rpm. It stayed at 67.5 until ~5.3rpm, which is when the HP crossed above it, and fell gradually back to 60ftlbs at the rev limit.

So without pictures, do I have a better torque curve? Is having lower TQ for a longer time w/ a slight HP increase better then more TQ for a shorter time?

Now, I was a little lean, Actually probably too lean at important times. So I'll be playing with a 185 or 190 jet to correct this. I know the "what cam is best" debate will rage on for centuries. I chose the N4 because I believed the N2 might not have much edge over the Sport's W cams.

So before I go playing the trial and error game (which is time consuming and costly) I thought I could get y'all's opinion. Let me have it! Is this the worst setup you ever saw? Was I better off before I started? Or do I only need some minor adjustments? Or am I good to go and don't know it?

My opinion:
Lose the drag pipes.
Some back pressure in the exhaust should help,at least with the tourque.
You lose lowend with drags.
1200 Sport begs for a nice 2 into 1.

Are we sure that the cams were indexed correctly when installed? Maybe one is lined up one tooth off...

Did you shim the needle any after the cam install? What did the A/F ratio look like on the dyno?

With the later intake close event of the N4's, the mid-range reversion of the drag pipes is probably more pronounced now than before and shows the drop in torque.

Are we sure that the cams were indexed correctly when installed? Maybe one is lined up one tooth off...

Did you shim the needle any after the cam install? What did the A/F ratio look like on the dyno?

With the later intake close event of the N4's, the mid-range reversion of the drag pipes is probably more pronounced now than before and shows the drop in torque.
I stared at the cams for a long time before I put the cover back on...not likely, but they could be off by a tooth. I hope not.

No shimming, the A/F was lean, ~14-15 the whole run.

The drags are gone, I have SE Pro II slip-ons.

another thing to look at also, is this the same dyno you used last year? you can get very different numbers from one machine to another.

if you get a good non-drag pipe exhaust you will get more like 85+ hp! go with V$H, thunderheader,Etc. they cost but are worth it!!!

Kinda of odd that you lost torque with the slip-ons..

i think:

you lost some dynamic compression when you installed the cams, you need to bump it back up to get the hp and tq where they should be,

thinner head or base gaskets, or better yet, a nrhs complete top end ?

i think:

you lost some dynamic compression when you installed the cams, you need to bump it back up to get the hp and tq where they should be,

thinner head or base gaskets, or better yet, a nrhs complete top end ?

I'm running 9.7:1 compression with my N4's, and gained all kinds of power when I swapped them in....

He has slightly more compression than I do, so I don't think this is his issue.

JMO....

static -vs- dynamic compression,

cam swaps do not effect static, but they do change dynamic

how have you measured the compression ?

the squish is set to ? ???????

I went with se.536's and had less than optimal dyno results untill addressed squish and compression issues.


the easiest way, in my opinion ??? warm up motor, unplug the coil and remove spark plugs, insert compression tester in to sparkplug hole, open throttle all the way, hit the starter button for about 5 sec.

if your not over 200 (mines about 215-220) build up the compression.


also check the ignition timing, Crim and I found about 4 degrees of retard (not advance) makes em our 98/99 1200s' about right

another thing to look at also, is this the same dyno you used last year? you can get very different numbers from one machine to another.
Here's an update.
First, no it was not the same dyno. BUT, today I went back and ran it again on the same dyno as last summer. Numbers were a little better, but still not what I was hoping for.

The guy who ran the dyno was very helpful, though, and I feel much more confident. He did two pulls for me. On the first, I averaged 75hp (up from 69.5 last summer) and 74.5tq (the same as last summer).

On the second pull, he acted on a hunch and let the choke out 1/3 of the way. 76.09hp and 77.05tq. His hunch was that the 40mm carb is not enough for my setup. So I guess a new carb is my future.

Also, I discovered a big error on my re-jet job: for some reason I assumed I had a 170 jet stock, so I put a 180 in it. Just did a little more reading, and realized the 1200S has a 190 jet stock :doh No wonder I'm really lean.

I was also browsing sportster.org and found something that suggests the power I'm getting with my setup is probably right on the money, high 70's once I straighten out my carb.

Can't wait to re-jet (again) and see. Than maybe later I'll get a 44mm carb or something.

Also, I discovered a big error on my re-jet job: for some reason I assumed I had a 170 jet stock, so I put a 180 in it. Just did a little more reading, and realized the 1200S has a 190 jet stock :doh No wonder I'm really lean.

Aha! I wondered how that 180 got in there. Never heard of a Sport model with less than a 190. I don't know how your new cam will affect things, but you probably should have a 195 and 200 main jet on hand for your next pulls.
Until you approach 100 HP, a different carb won't do much more than lighten your wallet. Save your money and talk to NRHS about some headwork. The Lightning heads on our Sports are so-so. Better'n standard, but not as good as T-Storms or the '04+ heads.

I think I'll start with a 195. If I can pull in the high 70's, maybe even hit 80, I'll be plenty happy.

I am no expert on the matter. All I know is what I've read by some of the experts that share their wealth of knowledge with us (Thank you Aaron of NRHS). I run N4s and it works well with the other two very important components that I have: T-Storm Heads and a 2 into 1 exhaust (85 hp 80 Tq SAE). One of the things that I read that has really stuck with me is that your performance is not defined by the sum of the parts on your bike but by the one that is holding the performance back. I believe Aaron has written that here on several occassions. I don't know the specs but judging from your numbers, I suspect the N4 probably has a later intake closing than the Sport cam thereby pushing your power higher up in the rpm range. You saw higher torque numbers, higher in the RPM range meaning you had better cylinder fill there. Your performance on the low end is suffering. If you want better performance on the low end, then go back to the Sport cams. If not, I believe you'll have to go with higher compression heads and a good exhaust to compliment your head choice. Again, I'm nothing close to an expert. I suggest you go back and read some of the very informative archives and check out the articles on this website: http://www.nrhsperformance.com/tech.shtml

Good luck in whatever you choose to do.

You're new numbers (with it richened up a bit) sound spot on to me...maybe even a little higher than I would have expected, though the cams are probably responsible for that.

As was stated before, the heads on your 1200S are better and worse than others. They were basically a standard head with more material in the combustion chamber to bump the compression. More compression means more power, but it also shrowded the valves a bit, so there can be some flow issues with them. Like was said, better than the standard head that were out at the time, but nowhere near what an XB (04+) is cabable of.

But agin, I'd be very happy with the numbers you'll be at with that jet change.

One of the things that I read that has really stuck with me is that your performance is not defined by the sum of the parts on your bike but by the one that is holding the performance back...
That's absolutely true. I had thought that maybe my new ICM was retarded, and maybe I would get a better curve with the original ignition...just a thought. But I couldn't find anything that says t he SE ICM (6,800rpm) is retarded.

I will rejet some time this week. (Like I said, a glaring error on my part) and pull again sometime in the near future. For fun, and if the dyno guy and I get along, maybe he'll let me do a pull with the SE ICM, then quick switch to the original, just to see the difference.

I think I'm pretty much squared away on this one. Thanks guys!

The other day I finally rejetted. I used a 200 main, and wow what a difference. I didn't realize how much the bike was hesitating on acceleration until after I made the switch. From a stand still with the 180 jet, the bike would bog when you first hit the throttle, and wouldn't begin to really take off until about 2.5rpm. Now it blasts off right from the start! Awesome.

I'm not worried about another dyno pull, so I probably won't do it for awhile.