Ironhead Cam Performance Opinion

[chevelle]

I have done quite a bit of dyno experimentation using many different cams,carbs,exhaust on my stock 900 and my 4&5/8" stroked 900 as well as others but I will only touch on the above 2 bikes here.

(I have zero stock 1000 experience, but can only assume the same info applies to a stock 1000.)

Let me emphasize all this info is for stock 900's, bigger engines are a different story.

I have come to realize the guys at the factory knew their shiet,
and long before computer technology and digital dyno setups.

I used to think of the stock P cams as just that, stock P cams.
I think it has alot to do w/ the catalogs w/ lists of aftermarket cams, there must be a better, higher performance cam for my bike right? In some performance applications yes I agree.
But think back to days before govt mandates and emissions, what would be the reason for the engine designers, builders to use a sub par camshaft... and these were the days before the screaming chicken (HD performance brand)
I have not tested all the aftermarket cams of course but as of yet I have not found a bolt in cam that performs as well as the stock P in a stock engine.
I will clue you in if I do.....

To elaborate some on the "performance increases" guys feel once a different cam grind (or other performance change) is installed.
This is not meant to point fingers or call anyone a liar of course, just to mention a phenomenon I have felt myself as well.
I have bounced this off of a couple very experienced performance guys as well, they feel the same way.

I am begining to realize this situation; that is when guys install a so called hotrod cam
and the engine now runs with a "different" characteristic or rides with a "different" feeling.
This feeling immediately tells the rider... WoW this is a definite improvement.
But just because it feels different does not alway mean better performance.

Some times also when a cam or exhaust or whatever is changed, in effect they are often (not always) losing power in certain critical crusing rpm.
So your crusing around with less power, but when you twist the throttle to say pass a car, you feel that rush that the "on cam" power gives you.
Any guys that have ridden 2 stroke dirtbikes, know what the "on pipe" feeling is, and this situation of the hotrod cam feels much the same.
It's a total false sence of power that is induced from the flat spot you were crusing around in, even when your bike is tuned as best a DIY'er can.
I have a sneaking suspicion that most all performance cams give this false sence of power, in a 900 that is.

Dont get me wrong, I know there are many improvements that can be made and these are true genuine improvements even w/o a dyno graph, but on these 900's they were close to optimal from the factory.
If you do not have a a before dyno run or ET, and a after to compare them to then do yourself a favor and stick w/ the P cams, because I have the graphs and so far have found no extra power in swapping cams.

Exhaust has been by far the best opportunity I have found for increasing power and torque.

Just what I have learned so far on these dinosaurs if anyone cares.
How many of you think im CRAZY ?????


900 thread: http://xlforum.net/vbportal/forums/s....php?t=1222275

Stroker thread: http://xlforum.net/vbportal/forums/s....php?t=1265958

2:1 thread: http://xlforum.net/vbportal/forums/s....php?t=1367025

[shovithead]

No, you are not crazy. Even though I do not do dyno work, i do build a bike or two and a lot of 900's have been through my shop, not to mention my own personal collection. You can make them faster, but a increase in cid is necessary, short of a quarter horse here and there. Pipes, are a better hp booster than carbs or cams. Even a sprocket swap can get you closer to what you desire. Remember, these bikes were built to compete with the british twins that were kicking the K's ass. So they built them to run, and run good. When the big twin guys mess with me, i say, i can beat them to the beer store. They say they can go to California much more comfortable than me. I tell them, how often do you go toCalifornia? And, how many times do you go for beer? Sportsters are fast, in the HD world.

[Dragstews]

.
.
.
....Yep.......There's No Replacement for Displacement......

Aaaaaaa unless it's blown...!! "If it's not Blown, It's gotta Suck"

[Threadkiller]

I'm no Sporty lover, but I can pay my respects....."Sportsters! Blowing away Big-Twins since 1957"

[texas rattler]

77 was a great year for sportys, add some p cams and carb/pipes and youl have a honkin sporty.

[Jtw79]

So if you were to stroke it would you run P cams or? You have my attention with your dyno pulls to prove it.

[Dragstews]

Stroke's like more duration ...........

[Jtw79]

That's what I would guess. Longer stroke= more volume to fill so you need to keep the valve open longer. So whose cam would have the specs to fit the bill?

[FeHd]

And makes it able to kick over.

[Dragstews]

Originally Posted by Jtw79

So whose cam would have the specs to fit the bill?

Aaaaa...Think there's a thread on here talking much about cams...

[Jtw79]

Okay you got me I need to search.

[Dragstews]

Originally Posted by Jtw79

Okay you got me I need to search.

I was going to ask Egor the name of it....But he's still out to lunch..

[Monte03]

Just what I have learned so far on these dinosaurs if anyone cares.
How many of you think im CRAZY ?????

Not Crazy at all Chevelle, you are a street rider that also has Dyno access, the info you are gathering is very interesting, looking forward to the Sifton 'H' cam reveiw..
I had changed my stock P Cams with Harley PB cams and you are correct, it changed the WoW factor (for a 55"er anyway) to further up the scale... an around Town stoplight to stoplite Sportster may be better served with the P .400 cams but dedicate funds on improving head flow with a good Porter..
Hey I remember buying a Lake Injector Carb when I was 21 thinking it's the new best hot setup.. we are all quick to search for the magic bullet only to find that there there are very few..
Monte

[chevelle]

Originally Posted by Monte03

Not Crazy at all Chevelle, you are a street rider that also has Dyno access, the info you are gathering is very interesting, looking forward to the Sifton 'H' cam reveiw..
Monte

I will let you know when I run the H's.
I'm hoping there will be some increase..... I'm not betting on it though.
Don't hold your breath.....

[Dragstews]

Originally Posted by chevelle

I will let you know when I run the H's.
I'm hoping there will be some increase..... I'm not betting on it though.
Don't hold your breath.....

If it wasn't a Huge undertaking to do a few dyno runs with the stock heads and then throw on a set that has the XLR valves and some port work...
Would love to see what the chart says on that....

This is pretty much what Branch did with his XR Hop-Up book...
Shoot....After pipes, carbs and cams. He even went to the trouble and time to add a windage tray in the sump for a few runs to see....

[chevelle]

Originally Posted by Dragstews

If it wasn't a Huge undertaking to do a few dyno runs with the stock heads and then throw on a set that has the XLR valves and some port work...
Would love to see what the chart says on that....

This is pretty much what Branch did with his XR Hop-Up book...
Shoot....After pipes, carbs and cams. He even went to the trouble and time to add a windage tray in the sump for a few runs to see....

I may do just that on my 4.625" stroker.
I have a set of Branch heads, and a set of stock to compare the two.
Although I believe even my stroker will be over ported w/ the 1.750" exh and 1.935" Int valves.
Again, this may be another lesson learned as far as bigger doesent always mean better.

[Dragstews]

.....Dyno Runs.....

Had the Buell at Daytona Bike Week a few years ago...

Alot of the portable Dyno's was in attendance....

Did a run at Carl's Speed shop...Showed great numbers on the chart....

Same night a few hours later went down to Gilly's Pub in New Symera and did another run....Shoot the number's was higher by 12 Horses .....

Pretty cool, I thought going 20 miles down the road and finding more Horse Power....



.....The Air was Heavy down there......

[chevelle]

Originally Posted by Jtw79

So if you were to stroke it would you run P cams or? You have my attention with your dyno pulls to prove it.

Im not so sure any cam will perform better than the P's on my small stroker either.

Check the stroker thread I posted.
You will see the P's are better than the PB+'s, that goes for both the stroker and the stocker.
I have yet to do alot of cam swaps on the stroker.
I ran some Andrews X cams and they did not perform well either (although I never posted runs), too much duration.

My stroker is also only 3' bore, I believe the larger bores of the 1000 may change things some.

[Jtw79]

So after reading all your findings on XL forum with Dyno graphs I am reluctant to change my cams, but more interested in stroking the motor. Already built a 2-1 with Supertrapp discs in a megaphone pipe. Wish I lived near you so I could see what my motor is doing or not doing on the Dyno. Really like all the info you are posting, keep it up.

[Jtw79]

So Chevelle have you had a chance to bolt on the Branch heads to see what they will do? Thanks!