Keihin CV 40 on 1/2 VW

[nicholsaz]

Hi Everyone,

I am new to this forum and have been digging around on this forum and numerous other sites on the internet.

I saw that years ago, Doug Stevens, in conjunction with Chester Thomas, used a Keihin CV 40 carb off off a Harley.
The initial statements were that it performed well and ran strong, but that is all I could find.
There doesn't seem to be any follow up since 2004 on this engine, or aircraft.

Any experience out there with the Keihin CV 40, with its altitude compensation on the 1/2 VW engine?

Thanks,

Mark Nichols

[Steve]

Here's a photo of the Doug Stevens engine...

Other top mounted carbs have performed as well as this was reported to work... Notable in this build is one item that should not be copied - the rubber bends are at great risk of collapsing from the intake vacuum, use metal bends and very short runs of rubber hose...

There are high speed (supersonic) air waves that reflect from one side of the engine to the other in the long intake pipe when the intake valves close... It is thought that the intake "T" intersection to the carb should be straight so the pressure waves are more inclined to go across the engine instead of partially out the carb...

30 - 40mm Carb sizes have been used successfully...

Any carb with an inlet butterfly valve should be installed with a means to
provide air inlet side carb heat...
The Keilin has a butterfly valve and you see carb heat provided in the photo...

[Steve]

An introduction to the Keihin CV 40 carb:

http://www.gadgetjq.com/keihin_carb.htm