I got the Sportster dyno tuned yesterday. The printout of my chart is very light, so I am trying to brighten it up with some photo software. Until then, I thought I would just list the results. I am running Andrews N-8 cams, heads ported by Skip's Custom Cycle of Winchester, VA, 12 to 1 Wiseco pistons with the combustion chamber opened a little around the intake valves to produce 10.8 to 1 compression, CV carb with Dynojet kit, SE Race Ignition tuner software and S&S mufflers using the stock headers, and a HurricaneFlow air cleaner setup. The bike is making 93.2 HP at about 6600 and 85.8 ft lbs of torque at about 5000. It is making over 70 lbs of torque from just over 2000 rpms and increases to over 80 at about 4000. The S&S mufflers produce the flatest torque curve with no midrange dip that I have ever achieved. The thing I liked the most besides the flat torque curve is that it makes 90 hp at 5700 and holds above 90 until about 6650.
The only bad news is that its too cold in VA this weekend go out to test it.


shooter

shooter ..... Nice numbers!

If you can make 90rwhp without installing the 1250cc kit on these engines, you are in great shape. :)

My motor came short of the 90 HP goal by 6. The engine was too lean, so I have changed the main jet to correct that. Also, I am shit-canning the SE slip-ons for a set of pipes that will make power. I don't have the programable ignition system like you do, but I certainly hope to make 89-90rwhp next time.

Using those high compression pistons really really helps to increase the low rpm torque that the big cams tend to take away. Good choice!

Again, congrats on the 93 HP and good torque numbers.

I guess it is time to take mine to the Dyno. 93 is a bunch. I doubt I have that but the compression, the cams. hi4 programmable, thunderheader, s&s, heads milled ported polished and titanium valves ought to get me close. I guess we will have to see when the wiring is done. How do you check compression ratio where the number is meaningfull.

Great Numbers Shooter, you did good. Any adjustments made to get to 93?? Going to get me one of those Hurricane ACs as soon as I can, still waiting on carb to get back.

Ditto, nice numbers there...

The final compression figure was calculated by my head porter after it cced the combustion chambers. Of course, every cam change will result in differences in actual compression figures.

Bill-The difference was adding a little advance to the ignition in the upper end of the rpm range and adding the dynojet kit. You may have noticed when you rode my bike that the low end wasn't very responsive. The new needle and spring, couple with a 190 main jet really made a difference. I am also sold on S&S slipons. They are not too loud, but they make incredible torque across the power band without taking away top end HP. You will have to ride it again to see the change.

Shooter

PS The amazing change at the dyno was a friend that I brought along with an 04 Ultra with a SE 103 motor running SE253 cams. He was running the same aircleaner that comes on a SE Electraglide. That is basically a stock airbox and filter with some slots cut in it. The base run was just over 80 HP and 85 torque. Eight runs later installing a new style SE breather kit with big filter, SE spitfire plugs and changes to the fuel map with Race Tuner software, he was making 96 HP and 110 ft lbs. He was so happy that I thought he was going to have to change his pants. Remember that next time you ask whether a good breather is worth the money.

Nice Numbers Shooter!!! :clap :clap

Ralph

The only way to accurately check compression ratio is by measuring and calculating...

As mentioned cc the heads, add the volume of the head gasket, add or subtract the volume of the piston deck height...if it's a positive deck then it needs to be subtracted, add the volume of the valve pockets....


All that is added to the volume the piston travels...bore*stroke and then the total is divided by the origional volume with the piston at the top



It can be done by filling the combustion chamber with oil and measuring it as it goes in.....this method is handy for domed pistons

so, If I have 50 thousandths milled off the heads. 0027 copper gaskets instead of .065, flat top pistons and a original 9 to 1 is it safe to guess I still have to measure. I still know it is way higher just because of the effort the starter goes through now. Much harder to turn it over unless the battery is fresh. I think it atleast more than the original 9to1 and probably closer to 10to1. Then comes all that cam stuff. I have n8's and they work. I am going to get it dynoed this year just to see how much it has. Hope it is not less than 80. I dynoed 72 in europe in 95 without cams, carb and head mods. Just ran great.

The problem with guessing is precisely that...it's guessing.

I've seen more than a couple of cc's different between heads so ya can get a ball park figure BUT ya never KNOW untill it's measured.


You will certainly have more than you had standard......

maybe around the 9 1/2++ : 1 region


Are you useing adjustable pushrods??????

as you've lost over 80 thou in height....

Yes on the adjustable pushrods. I thought I had to when I put the cams in so I ordered them at the same time. Still don't know why I needed them. I have read that you only need adjustables with the 550 lift cams but I suppose if the heads are closer to the cams that would sort of be the same.

Wow...what to say? Huge numbers and a few mysteries. Strong tq @ 2 k with n8s is odd. And good breathing past 6500 rpm to maitain your high hp is also rare. Your tech and whoever did your heads are to be congratulated.
What heads and what size valves. Beauty job...great hp and wide torque....
best I could get with similar build was 85 and 80.

Yes on the adjustable pushrods. I thought I had to when I put the cams in so I ordered them at the same time. Still don't know why I needed them. I have read that you only need adjustables with the 550 lift cams but I suppose if the heads are closer to the cams that would sort of be the same.


Your lifters only have a couple of hundred thou travel from memory..

So if you reduce the distance from lifter to rocker by too much then ya run out of travel in you lifter


The only reson for running adjustables is to set the lifter up correctly....standard pushrods are lighter...

so, If I have 50 thousandths milled off the heads. 0027 copper gaskets instead of .065, flat top pistons and a original 9 to 1 is it safe to guess I still have to measure. I still know it is way higher just because of the effort the starter goes through now. Much harder to turn it over unless the battery is fresh. I think it atleast more than the original 9to1 and probably closer to 10to1. Then comes all that cam stuff. I have n8's and they work. I am going to get it dynoed this year just to see how much it has. Hope it is not less than 80. I dynoed 72 in europe in 95 without cams, carb and head mods. Just ran great.


Did you cc the heads after milling? That's the big question. Your using .0027 gaskets? That's only 2.7thousandths. That's thin. Or .027 gaskets?

.0027 is only .099 CCs.
.027 is only 4.2 CCs
.065 is 10.1 CCs

Go here and punch in your info. It only works if your info is accurate.

Compression Ratio Calculator (http://www.rosspistons.com/calculator.php)

My info was
3.503 bore
3.812 stroke
54 head CCs
.030 gasket
.0001 deck height
-8.5 dish pistons
2 cylinders

It equals a nice 9.95 to 1

This is so much easier than doing math the long way.

He's probably got a head volume around 67cc give or take a few

And the head gasket will be 0.027" (Just about the absolute minimum ya can get away with......although a <= '03 1200 head has no quench area...)

maybe a zero deck height........

too many maybees, probablies and what iffs for my liking.....

I have the super thin copper gaskets. I also have original 1993 1200 heads that have been milled. It would be nice to know the compression ratio but it is not worth pulling the heads for. I will just say I have enough compression to make the battery work and too much to push start the bike. The rear tire always slides to a stop. Oh well. I will Dyno this summer eventhough the dyno won't make it go any better either. Suppose I could try jetting but it is real darn close.

I did not CC the heads because the guys at lakeshore HD told me I could not so I went to a machine shop and ask them to mill 50 off. I really think it was 60 but I am not positive. I wanted to try it even though Lakeshore HD told me not to. They also did a crap valve job where they ground the seats crooked. I posted a 72 on the dyno with crooked seats. That was a miracle. When my friend put his valve grinding toll on the seat he was suprised I did not feel the lack of a good seal as far off as they were. The valves were also burnt looking. We put in some titanium valves and cleaned up the ports port matched the intake and everything else he knew to do. He was a machinist by trade and in the HD business for 15 years. I assume he new what he was doing. Still like them gold colored valves.

[QUOTE=stevo]He's probably got a head volume around 67cc give or take a few[QUOTE]


Aren't they 67 CCs from the factory?

I was thinking they would be more like 62ish after taking .050 off.

Sorry....not clear...

started at around 67cc and lose 0.050" from there but it's not a linear measurement...

as you are taking that from a hemisphere...


as I said .....whatever we come up with it's guesswork ONLY....

I used stock 05 Roadster heads with stock valve sizes. They were ported and the chambers were opened up to reduce the compression of the pistons. The tuner attributed the strong torque at low rpm to the S&S mufflers.

Shooter


Wow...what to say? Huge numbers and a few mysteries. Strong tq @ 2 k with n8s is odd. And good breathing past 6500 rpm to maitain your high hp is also rare. Your tech and whoever did your heads are to be congratulated.
What heads and what size valves. Beauty job...great hp and wide torque....
best I could get with similar build was 85 and 80.

How important is knowing the engine's compression? I felt that it is important to know for when you are tuning, troubleshooting or even thinking about the next performance mod. How much of a role does knowing your compression ratio play when selecting a set of cams?

I got the Sportster dyno tuned yesterday. The printout of my chart is very light, so I am trying to brighten it up with some photo software. Until then, I thought I would just list the results. I am running Andrews N-8 cams, heads ported by Skip's Custom Cycle of Winchester, VA, 12 to 1 Wiseco pistons with the combustion chamber opened a little around the intake valves to produce 10.8 to 1 compression, CV carb with Dynojet kit, SE Race Ignition tuner software and S&S mufflers using the stock headers, and a HurricaneFlow air cleaner setup. The bike is making 93.2 HP at about 6600 and 85.8 ft lbs of torque at about 5000. It is making over 70 lbs of torque from just over 2000 rpms and increases to over 80 at about 4000. The S&S mufflers produce the flatest torque curve with no midrange dip that I have ever achieved. The thing I liked the most besides the flat torque curve is that it makes 90 hp at 5700 and holds above 90 until about 6650.
The only bad news is that its too cold in VA this weekend go out to test it.


shooter

Congrats to the awesome numbers! Can't wait to see what the dyno sheet looks like! Ever going to take her out to Richmond and see how she does?

How important is knowing the engine's compression? I felt that it is important to know for when you are tuning, troubleshooting or even thinking about the next performance mod. How much of a role does knowing your compression ratio play when selecting a set of cams?
I consider it part of the total equation myself...I don't know if you would be looking at ONLY what CR you are running (as I'm sure you know), but the cam specs, displacement, head design, fuel, etc, etc, etc. in the engine's "big picture"...for example...a 9.5:1 might be as high as one person wants to go while 12:1 would not be enough for someone else...it is certainly something you want to keep in mind when troubleshooting and thinking about performance mods but it is so tightly integrated into most of the performance modifications that I wouldn't say it was something seperate to consider when contemplating mods...instead I would say it is PART of the mods...i.e. if I use cam X with this piston Y and head Z then what will my actual CR be...not sure if I'm making sense here, but I'm sure that someone will be able to clarify better than me :D

Go here and punch in your info. It only works if your info is accurate.

Compression Ratio Calculator (http://www.rosspistons.com/calculator.php)
...
This is so much easier than doing math the long way.
Just to note that cam choice can really change the actual compression ratio quite a bit...the perfect classic sportster question is "Why can't I use 10:1 pistons with N2s to keep that low end torque"...due to the timing of the cams it results in higher than wanted (by most) compression ratios.
I know that a lot of people here know this I'm just posting it for those that don't.
This is one of the reasons I'm working on a calculator for the Actual Compression Ratio taking everything into account for our bikes.
Also for those that don't know much about this...listen to Stevo and Barry...these computations only work if you are accurate in your measurements...you can't just assume the volume of your heads as they can be off +/- quite a bit from what they "should" be.

How do you calculate the compression ratio with the cams involved in the formula?

http://www.rbracing-rsr.com/comprAdvHD.htm

Find all the details, and set your boost at zero. I believe stock rod is 6.926
this was accurate for mine.

I have an xl 1200 with n8 cams and I agree they are weak down that low. They rev well so I barley spend much time there. But his cr is high and that will keep those cams torquey. My bike was 60 lbs at 2000 and 68 lbs at 2500. High cr is gonna make some diff. But I forget to say in my last reply...THOSE ARE GREAT NUMBERS, MY BUDGET WAS ABOUT THE SAME...
IGN
HEADS
PIPES
INTAKE
PUSHRODS
ETC...ETC
I spent the wad like you, But YOUR #'S ARE GREAT WAY TO GO!
And I could only get 82 hp and 80 lbs.
So you did realy well. Obviuosly those n8s needed more cr, which I was going to persue but chose to add n20 instead.
http://img.photobucket.com/albums/v136/sonysucks/Our%20harley/N8_cams.jpg

oH YEAH, WHAT HEADS AND WHAT SIZE VALVES..883 SIZE OR 1200 OR LARGER.

He has 12:1 pistons, but he states 10.8:1 CR since the head chambers were opened up a bit. Even if he was a full point higher he isnt going to pull that kind of torque down low. No way. I have never seen a 1200 pull that kind of torque that low ever. I want to see a legitimate dyno on this setup.

I guess if you've never seen it, then it can't happen then ;) :shhhh

I havn't seen it either ...... but I've seen enough things to not say it's impossible....

Sorry....not clear...

started at around 67cc and lose 0.050" from there but it's not a linear measurement...

as you are taking that from a hemisphere...


as I said .....whatever we come up with it's guesswork ONLY....
no expert here but can't you get a good idea with ccp ??

what is CCP???????????????

sorry, its cold cranking pressure, or ya can do it hot, which is more accurate way to do it.

I used 1200 roadster heads and stock valves that my tuner spent some time on the flow bench tuning. Used bigger valve springs. He reported that the heads would flow 163 CFM at .600 valve lift. Unfortunately, I am running only .490 with these cams, so I am not getting the full effect of the head work. I have been thinking about getting some cams custom ground by Andrews with a higher lift. I tried it at the 1/8 mile and while it was quick (.791 at 88 MPH) I was disappointed that it wouldn't do better. The gearing is way too tall for drag racing. It would do over 80 in second gear. I have now changed to a Dyna rear sprocket with 70 teeth vs the stock with 68 and have just gotten an 883 sprocket with one tooth less for the front. A three tooth overall change should improve the 1/8 mile speed which I hope to check out next week without hurting my around town riding to much. I ride a Road King for long rides, so I dont' really care about mileage or highway driving with this one.

shooter

AT 7.91 for the 1/8th ain't too shabby , that's puttin ya at low 12's for the 1/4

Only ever ran an 1/8 mile once...I was hungover somethin fierce as we'd ridden up to a rally the night before and I had only stopped drinkin a few hours beforehand...it was at an airfield and the council had put some more emulsion down to cover the loose stuff...what a stuff up that was...the race bikes couldn't get any traction and I ended up second fastest qualifyer on my street sporty at 7.57.....I won the Harley bracket and gave it to the rest of the jappas and race bikes at the presentation...
Someone said "how embarrsin to be on a Harley" .....to which I replied "not half as embarrasin as being out qualified by one".......the crowd laughed at that....and the other lad went REAL quiet... :D:D:D

As I get braver and lower my launch time (.624), the time should come down closer to yours. I really think the two sprocket changes are going to help. I can tell a difference on the street already with the Dyna rear sprocket and I think that the smaller front one will help more. Unfortunately, these new bikes are also hauling about 50 extra pounds over your older model. I guess I will have to go on a diet to even the match. LOL!

Shooter

Your reaction time has NO effect on your Elapsed time...

I have 11 second time cards with .8+ and .4 reaction times

The timer for run start as soon as you brake the beam.....doesn't matter if ya got a 1.5 sec reaction or a .401 ....it doesn't change the time it takes you to do the run...

This is a common miss-conception tho....

Imagine your dial in/run time as a block of time.....the closer you can get that block of time to a perfect reaction time then the earlier your block of time will arrive at the other end...but the block of time doesn't change (unless you run a different time of course)...


It's not like a 100 metre foot race in that the time starts from the gun......that's where most people have difficulty with it...
the gun goes off BUT your TIME doesn't start untill you trip the beam...

You can sit at the line for 3 seconds and then go... that 3 seconds is NOT added to your time to do the 1/4


If ya still not clear (it takes some people quite a while to get their head around it) I can scan and post some time cards and draw a diagram that I usually use to explain it....it's somethin ya need to UNDERSTAND and then keep it to yaself ...as it's the key to winning in "Dial your own"..

Stevo, Thanks for the correction. I knew that but had a brain fart. At least I have gotten my carb to stop farting.
I am going up tonight to try the new gears.

Shooter