head volume
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
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From: Haslet Texas
Are you talking about EVO heads (this is the EVO section after all) or are you talking about the heads of your 96" motor that is in your signature?
Club Member
Joined: Aug 2008
Posts: 22,855
Likes: 17,906
From: Lafayette, Louisiana
I was wondering how you measured it.
Road Captain
Joined: Aug 2012
Posts: 625
Likes: 102
From: New Albany, Ms.
I think around 82cc . Sounds like yours have been cut. You can also measure from the head gasket surface to the top of the rocker cover gasket surface & uncut height should be around 3.740, give or take a few thousands.
Ride Safe,
Harold
Ride Safe,
Harold
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
Thanks, for the info and the suggestion to measure the head, hadn't even considered doing that.
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
http://www.nightrider.com/biketech/h...ompression.htm
I have around 9.73:1 compression; good for the ev51
This also confirms my volume measurement when put in the Big Boyz compression calculator, which was producing less compression, 9.34:1
Not sure which one is more accurate, but the bottom line is that at least whoever did the work didn't just put the wrong cam in it.
Thanks again for the info.
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Road Master
Joined: Feb 2014
Posts: 913
Likes: 5
From: indiana
stock is suppose to be 83cc but it can be anywhere from 81cc to 85cc. if yours are 74 they have been cut thats the volume that most hot rod builders shoot for. with 74cc heads .030 head gasket wiseco 10:1 pistons .003 in the hole and a wood w-9 cam will give you 11:1 static compression and 9.67:1 corrected that's as high as you can go on pump gas.
with flat top pistons and ev51 cam your static would be 9.3:1 and corrected is 8.4:1
with flat top pistons and ev51 cam your static would be 9.3:1 and corrected is 8.4:1
Road Master
Joined: Feb 2014
Posts: 913
Likes: 5
From: indiana
Just measured the head at 3.656" so if your number is near correct than the head is shaved down around .080" and according to this chart,
http://www.nightrider.com/biketech/h...ompression.htm
I have around 9.73:1 compression; good for the ev51
This also confirms my volume measurement when put in the Big Boyz compression calculator, which was producing less compression, 9.34:1
Not sure which one is more accurate, but the bottom line is that at least whoever did the work didn't just put the wrong cam in it.
Thanks again for the info.
http://www.nightrider.com/biketech/h...ompression.htm
I have around 9.73:1 compression; good for the ev51
This also confirms my volume measurement when put in the Big Boyz compression calculator, which was producing less compression, 9.34:1
Not sure which one is more accurate, but the bottom line is that at least whoever did the work didn't just put the wrong cam in it.
Thanks again for the info.
don't use that chart its wrong you never just mill so many thousandths off a head always cc them.