Fuel octane question - Page 6 - Harley Davidson Forums

Notices
Sportster Models 883, 883 Custom, 1200 Custom, 883L, 1200L, 1200S, 1200 Roadster, XR1200, and the Nightster.
Sponsored by:
Sponsored by:

Fuel octane question

  #51  
Old 01-11-2019, 09:52 PM
handirifle
handirifle is offline
Senior Rider
Thread Starter
Join Date: Sep 2018
Location: Somewhere out west
Posts: 473
Thanked 16 Times in 16 Posts
Default

Apache
Thanks, I assume those tripple digit bikes with .536 cams, also have headwork done as well, to reach those levels? The cam lope was pretty obvious in that video.

Taht kind of money will most likely never be in my hands for a hop up job, but nice to see what can happen when it is.
 
  #52  
Old 01-11-2019, 10:03 PM
apache snow's Avatar
apache snow
apache snow is offline
Road Captain
Join Date: Sep 2017
Location: over the mountain
Posts: 723
Thanked 146 Times in 123 Posts
Default

It don't cost as much as you think. Especially if you do your own work. Mine is right at 110 hp Motor work was around $2500.if I remember correctly.
 
  #53  
Old 01-11-2019, 10:28 PM
handirifle
handirifle is offline
Senior Rider
Thread Starter
Join Date: Sep 2018
Location: Somewhere out west
Posts: 473
Thanked 16 Times in 16 Posts
Default

Yea too rich for this ole retired mans blood sadly.
 
  #54  
Old 01-11-2019, 10:32 PM
TriGeezer's Avatar
TriGeezer
TriGeezer is offline
Supporter
Join Date: May 2012
Location: San Diego County, CA
Posts: 12,475
Thanked 2,908 Times in 1,646 Posts
Default

This topic always upsets me, and gives me gas.
 
  #55  
Old 01-11-2019, 10:42 PM
handirifle
handirifle is offline
Senior Rider
Thread Starter
Join Date: Sep 2018
Location: Somewhere out west
Posts: 473
Thanked 16 Times in 16 Posts
Default

High octane I hope
 
  #56  
Old 01-11-2019, 10:53 PM
TriGeezer's Avatar
TriGeezer
TriGeezer is offline
Supporter
Join Date: May 2012
Location: San Diego County, CA
Posts: 12,475
Thanked 2,908 Times in 1,646 Posts
Default

Originally Posted by handirifle View Post
High octane I hope
Definitely,,,
 
  #57  
Old 01-12-2019, 11:01 AM
pistondealer
pistondealer is offline
New Member
Join Date: Sep 2017
Location: Hastings MN
Posts: 57
Thanked 10 Times in 9 Posts
Default

Originally Posted by aswracing View Post
Compression ratio is only half the compression formula. Cam timing is the other half.

You can only build compression when both valves are closed. Well, as the motor starts it's compression stroke, the intake valve is still hanging open. So the piston starts coming up, but the intake valve is still open for awhile, and no compression is building.

The reason for later intake close points is high rpm torque, which is better known as "power". The idea is to keep filling the cylinder as the rpm rises. Cylinder fill keeps happening during the early stages of the compression stroke because the incoming fuel has inertia.
But..................................the later intake closing along with a early exhaust opening all by itself will raise cylinder pressure and performance. But.....................................if you do not raise the compression ratio also you will need to run at 6,000 RPM all day, anything less and you'll probably get outrun by a Briggs & Stratton.
 
  #58  
Old 01-12-2019, 12:58 PM
apache snow's Avatar
apache snow
apache snow is offline
Road Captain
Join Date: Sep 2017
Location: over the mountain
Posts: 723
Thanked 146 Times in 123 Posts
Default

You know you are answering Hammer performance who does this for a living. LOL
 


Thread Tools
Search this Thread
Featured Sponsors
Vendor Directory

Contact Us About Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: