Pros and Cons of Compression Release Cams - Harley Davidson Forums: Harley Davidson Motorcycle Forum
Harley-DavidsonForums.com is an independent enthusiast website owned and operated by VerticalScope Inc. Harley-DavidsonForums.com is not sponsored by or in any way affiliated with Harley-Davidson Inc.. The Harley Davidson names and logos are trademarks owned by Harley-Davidson Inc.

Go Back   Harley Davidson Forums: Harley Davidson Motorcycle Forum > Technical > Performance

» Insurance
» Our Partners
»ATV Reviews
»Motorcycle Games
Reply
 
LinkBack Thread Tools Display Modes
Old 01-04-2013, 09:51 AM   #1 (permalink)
Senior Member
 
kg5ie's Avatar
 
Join Date: Sep 2012
Location: Weatherford, TX
Posts: 107
Images: 1
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.
kg5ie
2009 FLSTC
kg5ie is offline   Reply With Quote Quick reply to this message
Old 01-04-2013, 10:47 AM   #2 (permalink)
Senior Member
 
Join Date: Sep 2008
Location: Munnsville, N.Y.
Posts: 1,412
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"..........
Hillsidecycleco is offline   Reply With Quote Quick reply to this message
Old 01-04-2013, 03:05 PM   #3 (permalink)
Senior Member
 
98DARKHORSE's Avatar
 
Join Date: Feb 2012
Location: Britton
Posts: 544
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
98DARKHORSE is offline   Reply With Quote Quick reply to this message
Old 01-04-2013, 03:21 PM   #4 (permalink)
Grandstanding Member
 
Dave63's Avatar
 
Join Date: Jun 2008
Location: PA
Posts: 29,816
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.
__________________
__________________________________________
“When the going gets weird, the weird turn professional....” ~ Hunter S. Thompson~

R.I.P. Rubberdown. 1971-2012
Dave63 is offline   Reply With Quote Quick reply to this message
Old 01-05-2013, 05:54 AM   #5 (permalink)
Senior Member
 
Join Date: Sep 2008
Location: Munnsville, N.Y.
Posts: 1,412
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"..........
Hillsidecycleco is offline   Reply With Quote Quick reply to this message
Old 01-05-2013, 06:51 AM   #6 (permalink)
nitro freak
 
prodrag1320's Avatar
 
Join Date: Jul 2009
Location: DELAND,FLORIDA
Posts: 1,162
Images: 5
we use them & like them
__________________
kirby-vee twin racing
AMRA champion, AMRA & AHDRA record holder
prodrag1320 is offline   Reply With Quote Quick reply to this message
Old 01-05-2013, 03:24 PM   #7 (permalink)
Senior Member
 
98DARKHORSE's Avatar
 
Join Date: Feb 2012
Location: Britton
Posts: 544
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
98DARKHORSE is offline   Reply With Quote Quick reply to this message
Old 01-07-2013, 07:21 AM   #8 (permalink)
Senior Member
 
Join Date: Sep 2008
Location: Munnsville, N.Y.
Posts: 1,412
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"..........
Hillsidecycleco is offline   Reply With Quote Quick reply to this message
Old 01-07-2013, 08:10 AM   #9 (permalink)
Millwright
 
petew's Avatar
 
Join Date: Oct 2011
Location: Idaho
Posts: 208
I still miss that bottom end though, Scott.
__________________

103" w/Race Kit,Stage IV 117HP 111TQ
SE 259E Cams
SE Heavy Breather AC (Scott's modified)
SE Race Tuner
V&H Power Duals & Hi Outputs
SE CNC Heads 10.62/1 w/SE 58mm TB
John Scott port matching
Renegade Racine wheels. 21x3.5/ 17x6.25
http://www.harley-davidsonforums.com...845-petew.html
petew is offline   Reply With Quote Quick reply to this message
Old 01-07-2013, 10:49 AM   #10 (permalink)
Senior Member
 
Join Date: Jun 2012
Location: South Charleston, WV
Posts: 294
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.
Instructor is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Harley Davidson Forums: Harley Davidson Motorcycle Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 05:21 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
This site is in no way affiliated with Harley-Davidson
Motorcycle News, Videos and Reviews
Honda Grom Forum Harley Davidson Forum Honda 600RR Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum Ducati Scrambler Forum