freelancethink

Search This Blog

Harley Davidson bobbers worth blogging about, plus a few yamaha and triumphs

September 24, 2011

Get link
Facebook
X
Pinterest
Email
Other Apps

Get link
Facebook
X
Pinterest
Email
Other Apps

Comments

honda xr250 by low brow customs

History of the harley Davidson sportster

when old is new again

Researching the air-cooled Honda XR650 L engine I came across the acronym RVFC cast into the valve head. RVFC or Radial Four Valve Combustion was a proprietary valve arrangement created by Honda to make a four valve head flow more like a hemi head. Honda RVFC or Radial Four Valve Combustion, splays the valves radially away from the bore's axis and creating a hemispherical combustion chamber when viewed from the engine's profile. The splayed valves arrangement allows quicker flame propagation across the combustion chamber, allowing the engine to produce more power at a given RPM. Additional benefits include better cooling and the engine's timing can be more radically advanced. MV Agusta's new 750cc inline-four uses a radial valve configuration because the engine utilizes a small stroke relative to its bore. A smaller stroke will allow an engine to rev to higher RPMs and produce large amounts of horsepower but when we reduce an engine's stroke it will produce l...

Powered by Blogger

sean coker