Pros and Cons of Compression Release Cams - Harley Davidson Forums: Harley Davidson Motorcycle Forum
 
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post #1 of 10 (permalink) Old 01-04-2013, 09:51 AM Thread Starter
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Pros and Cons of Compression Release Cams

Looking at new cams. What are the pros and cons of compression release type cams? I know the basic idea is to save starters and possibly batteries....hype or truth?

That said...I would like to hear from someone who has them and from some wrenches who have installed them a true opinion....not just the sales propaganda.

Thnx,

Bill D.
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post #2 of 10 (permalink) Old 01-04-2013, 10:47 AM
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Quote:
Originally Posted by kg5ie View Post
Looking at new cams. What are the pros and cons of compression release type cams? I know the basic idea is to save starters and possibly batteries....hype or truth?

That said...I would like to hear from someone who has them and from some wrenches who have installed them a true opinion....not just the sales propaganda.

Thnx,
No hype, they do just what they are intended to do. E-Z start.
We've installed them with our kits, and our clients love 'em.
Saves the cost of machining for releases.
BTW, this feature has been on the kneescrapers for quite some time, and the V-Rods have them as well.
Good product, from a great company.
Scott

"....3 dueces and a 4 speed..........and a 389"..........
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post #3 of 10 (permalink) Old 01-04-2013, 03:05 PM
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im not willing to spend the extra money on releases (granted i have an evo and dont beleive they make them for my cam) as far as the head goes im not going to pay for the releases to be installed either

i had 200psi in my cylinder and my starter turned it over everytime with no fuss, i did however install the yuasa HD battery with more CCA over factory for my bike

i dont feel it becomes a real issue untill you go to a really large bore were the psi starts to take a toll on the starter

most dont run more then 190psi on the street simply because they are worried about knock and bad gas, you have to have you ducks in a row to run 200+psi on the road with pump gas(including jetting, ignition timing, and the ability to help cool the motor with oil cooler and colder plugs)

so i would say unless you are running a 113 big bore with high compression (and im not talking 10.5:1 because NO ONE runs 10.5:1 on the street i dont care if thats what your pistons are labeled, that doesnt matter it comes down to elevation, cam timing, rod length and stroke most people rarely see over 9.25:1 which is like 192psi

i suppose some like to tell everyone about there compression releases and play with them before they start the bike

ive got 11:1 wisecos in my bike, i was told it would never run on the street, i live in michigan and have rode to milwaukee and rode out in sturgis....no issues or knock

98 Evo 83.5ci, custom cam, 44cv, lightened ballanced crank, H-Beam rods, beehive springs, tapered pushrods, johnson hylift lifters, SE slip-ons no baffle, 101.78 hp @ 6200rpm
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post #4 of 10 (permalink) Old 01-04-2013, 03:21 PM
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Quote:
Originally Posted by 98DARKHORSE View Post
im not willing to spend the extra money on releases (granted i have an evo and dont beleive they make them for my cam) as far as the head goes im not going to pay for the releases to be installed either

i had 200psi in my cylinder and my starter turned it over everytime with no fuss, i did however install the yuasa HD battery with more CCA over factory for my bike

i dont feel it becomes a real issue untill you go to a really large bore were the psi starts to take a toll on the starter

most dont run more then 190psi on the street simply because they are worried about knock and bad gas, you have to have you ducks in a row to run 200+psi on the road with pump gas(including jetting, ignition timing, and the ability to help cool the motor with oil cooler and colder plugs)

so i would say unless you are running a 113 big bore with high compression (and im not talking 10.5:1 because NO ONE runs 10.5:1 on the street i dont care if thats what your pistons are labeled, that doesnt matter it comes down to elevation, cam timing, rod length and stroke most people rarely see over 9.25:1 which is like 192psi

i suppose some like to tell everyone about there compression releases and play with them before they start the bike

ive got 11:1 wisecos in my bike, i was told it would never run on the street, i live in michigan and have rode to milwaukee and rode out in sturgis....no issues or knock
Releases come stock on the 103" (Ultras since 2011) and 110" engines, right from the HD. If you're running a bike at factory specs, (Read: EPA 14.7:1 AFR) the added heat alone will warrant compression releases when the bike is hot.

If the bike were alowed to be sold running as rich as we'd all like, there'd be no need for them, in most cases.

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When the going gets weird, the weird turn professional.... ~ Hunter S. Thompson~

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post #5 of 10 (permalink) Old 01-05-2013, 05:54 AM
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Yep.
The OEM 110"ers that carry the 255(called the "school-bus" cam here) are between 205-207 ccp, right off the showroom floor, so you can bet your last dollar they are in DIRE need of those releases.
We have HO 80", and 89" Evo's that use releases.
Saves the battery, starter clutch, ring & spur gear, along with 18.9 lbs. of aggravation.
Scott

"....3 dueces and a 4 speed..........and a 389"..........
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post #6 of 10 (permalink) Old 01-05-2013, 06:51 AM
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we use them & like them

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post #7 of 10 (permalink) Old 01-05-2013, 03:24 PM
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Quote:
Originally Posted by Hillsidecycleco View Post
Yep.
The OEM 110"ers that carry the 255(called the "school-bus" cam here) are between 205-207 ccp, right off the showroom floor, so you can bet your last dollar they are in DIRE need of those releases.
We have HO 80", and 89" Evo's that use releases.
Saves the battery, starter clutch, ring & spur gear, along with 18.9 lbs. of aggravation.
Scott
205ccp...no kidding im surprised they are pushing them up that high, throttle response must be nice on them things

98 Evo 83.5ci, custom cam, 44cv, lightened ballanced crank, H-Beam rods, beehive springs, tapered pushrods, johnson hylift lifters, SE slip-ons no baffle, 101.78 hp @ 6200rpm
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post #8 of 10 (permalink) Old 01-07-2013, 07:21 AM
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The timing of that emmisions cam is very odd.
Once tuned, they do give the rider the sensation of that the bike is going to go, go, go, but once they hit about 4000 rpms, the party is over.
Scott

"....3 dueces and a 4 speed..........and a 389"..........
Goodson H-D Cylinder Head Tooling Manufacturer
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post #9 of 10 (permalink) Old 01-07-2013, 08:10 AM
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I still miss that bottom end though, Scott.


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post #10 of 10 (permalink) Old 01-07-2013, 10:49 AM
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I'm running JIMS 120 motor w/ manual compression buttons and was told that if making a practice starting without using them, plan on new starter pretty quick. Have forgotten a couple times but also learned I had better have gloves on or be very quick in pushing down for those buttons get very hot to the touch. Done it so many times now it has become a habit and when through riding bike, punch the buttons so as to not forget next time I start it.
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