Irving Vincent V-Twin Personal Best Dyno Run

bmetcalf

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Is that an external vacuum pump for engine breathing from the front intake adjuster cap? Also, I wonder what the purpose of that long perforated assembly hung on the G50 plate is? In the K/S area, maybe the power takeoff for the brake, but the long length?
 

Cyborg

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I gather it’s their sidecar engine?? so maybe the plates have something to do with that although they don’t seem to be visible when the bike is assembled.
Not sure about the vacuum pump... looks more like a glorified catch tank, but that wouldn’t explain the gauge on the bottom of the tank. I recall seeing a photo of a twin with a vacuum pump installed, but don’t recall if it was Irving.
The drag racers in the US used vacuum setups... just plumbed into the exhaust to help retain oil. They discovered it also added a bit of hp. Then switched to vacuum pumps when the people against everything complained about the noise and mufflers meant plumbing into the exhaust wasn’t an option. You can still buy kits to plumb a breather into the exhaust on small aircraft. I don’t have any hands on experience with vacuum pumps, but I’d be cautious about sucking any of that precious oil mist out of the engine.
 

bmetcalf

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Since a dragster finishes in ~7 seconds, they have a chance to top it up right away. :)
 

Cyborg

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It’s interesting when you calculate the number of engine revolutions between the green light and the finish line...

It’s not so much the oil level I was thinking of, but the mist or oil fog that helps lubricate things. Maybe not a concern in something that is totally pressure fed?
Maybe not a concern for that engine in the video ...I would imagine it’s oiling system has been improved somewhat. Anyway, just guessing.
There is another video of the sidecar and in the comments he says the HP is “around 175”.
 
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