Question about advertised compression ratios
Thread Starter
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HDF Community Team
Joined: Apr 2018
Posts: 2,574
Likes: 1,068
From: Ohio
I am not sure why you think we might be arguing? No argument on 95cc for CVO or 110 heads. You asked what you were missing with the advertised compression ratio when your calcs came up with 10.06 as compared with the advertised 10.75. What was missing in your calcs was the OEM head gasket thickness and 85cc chamber volume which is what the manufacturer uses to develop advertised specs. Maybe I misunderstood your OP but did not intend to start an argument.
So if I understand you correctly even though all 110 heads measure ~95cc they are advertised at 85cc?
Grand HDF Member
Joined: Jul 2007
Posts: 3,740
Likes: 8,536
From: Bates County MO
No, I believe he is saying they are using the term SE heads, but using the 85cc measurement.
SE heads doesn't necessarily mean CVO heads. There were SE heads in the SE catalogs that never came on a production bike.
110 Heads usually come in at 95cc
103 CVO heads usually measure ~98CC
99-05 heads were typically 85 cc
06-17 96/103 heads at 86cc
Measure everything, so you get what you're looking for.
SE heads doesn't necessarily mean CVO heads. There were SE heads in the SE catalogs that never came on a production bike.
110 Heads usually come in at 95cc
103 CVO heads usually measure ~98CC
99-05 heads were typically 85 cc
06-17 96/103 heads at 86cc
Measure everything, so you get what you're looking for.
Thread Starter
|
HDF Community Team
Joined: Apr 2018
Posts: 2,574
Likes: 1,068
From: Ohio
No, I believe he is saying they are using the term SE heads, but using the 85cc measurement.
SE heads doesn't necessarily mean CVO heads. There were SE heads in the SE catalogs that never came on a production bike.
110 Heads usually come in at 95cc
103 CVO heads usually measure ~98CC
99-05 heads were typically 85 cc
06-17 96/103 heads at 86cc
Measure everything, so you get what you're looking for.
SE heads doesn't necessarily mean CVO heads. There were SE heads in the SE catalogs that never came on a production bike.
110 Heads usually come in at 95cc
103 CVO heads usually measure ~98CC
99-05 heads were typically 85 cc
06-17 96/103 heads at 86cc
Measure everything, so you get what you're looking for.
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
Road Warrior
Joined: Sep 2014
Posts: 1,872
Likes: 1,325
From: DeLand, Florida
All performance kits are “advertised” to give the best possible outcome as most people buy on impulse from this advertising.
the only way to truly know is to cc everything yourself. Not hard to cc heads if they are off using a syringe and a liquid of your choice - I use alcohol.
the only way to truly know is to cc everything yourself. Not hard to cc heads if they are off using a syringe and a liquid of your choice - I use alcohol.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,923
Likes: 8,027
From: poway
All performance kits are advertised to give the best possible outcome as most people buy on impulse from this advertising.
the only way to truly know is to cc everything yourself. Not hard to cc heads if they are off using a syringe and a liquid of your choice - I use alcohol.
the only way to truly know is to cc everything yourself. Not hard to cc heads if they are off using a syringe and a liquid of your choice - I use alcohol.
I use alcohol too but not to CC heads..
Robin also missed the early SE heads that were 78-80 ccs.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,923
Likes: 8,027
From: poway
While some may like conspiracies, I do believe that the advertised CRs and CCs can also be off due to simple errors. For instance, Wissco screws up regular.
They state that their current one of their 4.125 , 4 inch stroke pistons are 10.5 to 1. With stock chambers they are closer to 11 to 1. Their early 10.5 to 1, 95 ci pistons were advertised as 10.5 ccs. When measured they were closer to 14ccs. Nice unexpected compression bump..
They state that their current one of their 4.125 , 4 inch stroke pistons are 10.5 to 1. With stock chambers they are closer to 11 to 1. Their early 10.5 to 1, 95 ci pistons were advertised as 10.5 ccs. When measured they were closer to 14ccs. Nice unexpected compression bump..
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Road Warrior
Joined: Mar 2013
Posts: 1,923
Likes: 587
From: Alorton, Illinois
I just always assume advertised anything was meant for stock applications. There is no way to target all possible mods. There will always be variations from deck height and chamber. Always measure everything.
Banned
Joined: Sep 2009
Posts: 3,569
Likes: 624
From: deland,florida
It's best to always cc your chambers.we use CP Piston kits here and go by dome volume,more than advertised ratio's (that said, advertised ratio's will get you in the ball park). Heads are then set at the cc amount to yield the compression ratio wanted