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post #1 of 13 (permalink) Old 11-21-2012, 09:51 AM Thread Starter
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Need Cams explained

I have a basic understanding of lobe & duration but what exactly are the differences or the deciding factor when you picked your cam ?
My question is really for us average Joe's that are doing only a stage 1 and want to add an aftermarket cam to make a little more get up & go off the line as well as mid range.... I guess I want it all ; an all-around-cam that will improve my Off the line jump as well as highway speeds........ Is that possible.?

Ive seen 777, 555 , 254 , 222


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post #2 of 13 (permalink) Old 11-21-2012, 01:51 PM
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a VERY simple explanation is to look at duration & int closing for compression(under 235 like stock comp.,235-240 around 9.5-9.8,240-250 around 10.0-10.5,250up 10.5-1 & up).plus the earlier the int opens & closes will make power lower.a nice "all around" cam set is the S&S .570`s,set @ 9.8-1
post #3 of 13 (permalink) Old 11-21-2012, 04:39 PM
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My 2 cents ride your bike normal for a while and pay close attention to how you drive, where in the rpm range you do most of your driving. This will help you in finding the cam. If your looking for a low and mid range there are a lot of cams that fit the bill and comes down to your pick. if you email any of the suppliers they will express thier favorite or perferred cam for your bike and what your looking for. You have to enjoy it have fun.

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post #4 of 13 (permalink) Old 11-21-2012, 05:31 PM
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Originally Posted by prodrag1320 View Post
a VERY simple explanation is to look at duration & int closing for compression(under 235 like stock comp.,235-240 around 9.5-9.8,240-250 around 10.0-10.5,250up 10.5-1 & up).plus the earlier the int opens & closes will make power lower.a nice "all around" cam set is the S&S .570`s,set @ 9.8-1
holy shit.... i would h8 to see the VERY complex answer!

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post #5 of 13 (permalink) Old 11-22-2012, 01:29 AM
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Some Things To Consider
Not everyone’s bike or riding style is the same. Camshaft selection must be based on what you’re looking for as well as the component parts and accessories being used on the motorcycle. The installation of the right cam can produce both performance and reliability. Here are the key factors to consider:
1. Riding Style
Is the bike for weekend use or your main form of transportation? Is the bike being used for short trips around town “from light to light”, or for touring long distances? What terrain do you ride? Is high performance or racing your primary concern?
2. Weight Of The Bike
What does it weigh? Is it light, or weighted down with accessories? Do you tow a trailer or have a side-car? Do you ride solo or tandem?
3. Operating RPM Range
What gearing does the bike have? How many speeds to the transmission? Does the bike have “International” gearing? What rpm range are you most likely to be operating in?
4. Engine Displacement
And Compression Ratio
What cubic inch is your engine and what compression ratio does it have?
5. Engine Modifications
And Engine Accessories
To obtain the maximum potential from your bike it is important to have engine components that are compatible. The components, accessories and modifications to consider are:
a. Air Cleaner Filter, Jetting
b. Exhaust System
c. Ignition System
d. Carb Size, Style, or F.I.
e. Compression Ratio
f. Cylinder Head Modifications
1. Performance Valve Springs
2. Enlarged Valve Diameters
3. Porting, Polishing, Milling
g. Aftermarket Cylinder Heads
h. Nitrous Oxide
i. Supercharger or Turbo
The Heart Of The Matter
An engine is a giant air pump and the more efficiently the air moves through it the more power the engine makes. The camshaft opens and closes the valves allowing the air to enter and exit. Camshafts differ in design, but the two main factors are the amount of “duration” and “valve lift”. The “duration” is the time the valve is open (measured in degrees of crankshaft rotation). Duration determines the “rpm potential” of the engine and power band. The longer the duration period the higher the RPM the power band will operate at. The “lift” is the distance the valve opens (it is measured in thousandths of an inch of travel). The more lift the more air/fuel mixture can enter and exit the engine, thereby producing more torque.
Bigger’s Not Always Better
The camshaft provides an “rpm power band” that is approximately 3,000 rpm wide. This rpm power band can be produced in either the Lower Range (from off idle to 3,500 rpm), in the Mid Range (from 2,000 to 5,000 rpm) or in the High Range (3,500 to 6,500 rpm). Select the camshaft that will perform the best in the particular rpm band that the bike will be operating in. The amount of valve lift that the engine can accept is often determined by valve to piston clearance, valve to valve clearance, and the amount of travel the valve spring can handle before its coils touch one another and bind up. Big lift camshafts could require modified cylinder heads or pistons and performance valve springs with additional travel.
Power vs Weight
The “horsepower to weight ratio” is very important. You must produce the right amount of power at the correct rpm range. A heavy bike normally needs a cam that will provide good lower rpm power (torque) to get the bike moving. Generally, a cam with less duration would work the best in a heavy bike. A lighter bike requires less low end power, therefore a cam that provides power in the higher rpm range would be better suited. But of course there are always the exceptions. A rider with a heavy Dresser who rides the open highway might not care how long it takes for the bike to wind-up to speed. He likes to ride at 65 mph and wants to pass up to 90 mph! In this case, a cam with increased duration and rpm potential would work best.

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post #6 of 13 (permalink) Old 11-22-2012, 03:11 AM
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Still Grumpy one other thing ~ the ole seat of the pants thing ~ on my 10 LTD my buddy & I had same setup 555's same exhaust ~ only difference is I had worked heads ~ his bike still pulled with mine to 90 or so then I could ease away ~ my point is all the specs really don't give you the feel of ridin em ~ Talk to folks ~ I never had a problem lettin a seasoned rider try out my bike with the 555's or the 777's ~ If you are thinkin about a cam maybe you know somebody or even the dealer with a used one that will let ya take it for a spin. We typically want our bikes to come on early, a buddy of mine bought a 120r and installed a woods cam before putting the motor in the bike ~ his cams come in at about 1800 ~ and drop off at 4k ~ this is how most of us ride. Not sure which cam it is but it is fun to ride.. TW???

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post #7 of 13 (permalink) Old 11-22-2012, 07:17 AM
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post #8 of 13 (permalink) Old 11-22-2012, 08:00 AM Thread Starter
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Thanks guys. There will definitely be alot to consider Thanks for all replies.!

Sent from my iPhone using Free App

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post #9 of 13 (permalink) Old 11-22-2012, 08:34 AM
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when you look at the specs , look at where the intake closes in degrees ABDC

early intake closing ( less than 30 degrees ) is a low speed torque cam
high torque at low engine speeds and lower hp at high engine speeds

30-50 degrees is the mid range cam

greater than 50 degrees is a high speed power cam

the mid and high give you higher hp at high engine speeds along with less torque at low engine speed

S&S 551 is where I am headed soon


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post #10 of 13 (permalink) Old 11-22-2012, 09:36 AM
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Here's what I've found out. TW777 great cam but likes higher compression and head work will work good just by itself. TW555 great cam likes the same thing but works great just by itself. TW222 works great just by itself. Is great for low compression big engines like the 103", but It also works well if you go with some higher compression and headwork. Confused now? I think I just confused myself! I haven't looked into the specs of other brand/cams. My head would explode then.

2012 FLTRX Denim Black,Stock head pipe with Cat removed w/ Jackpot 4" black slash up slip-ons. power vision, Fuel Moto pro billet A/C, Woods TW-222's, 12" Klock Werks . Sanchos Wings. Khrome werks 2+2 Handlebars.
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