Comments on: The new Horex motorcycle with VR6 engine: A Technical Analysis (Bike Reports) (News)

By: Norm G.

Norm G. — Thu, 05 Apr 2012 01:30:26 +0000

re: “If you wouldn’t go for a motorcycle in this price range over a car if you had the money then you just aren’t a true motorcyclist”

correct. he is nothing more than a consumer MASQUERADING as a “Motorcyclist”. we have a lot of that now in modern day. not that there’s anything wrong with that for that’s how most start out, but we’ve gotten to the point where we’re a little too “fast and loose” with that label. not all motorcyclists are “Motorcyclists” (capital M).

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By: John Tuttle

John Tuttle — Wed, 04 Apr 2012 21:52:58 +0000

Piston stroke affects more than the maximum safe rpm. It determines how far the air that has entered the chamber has to travel to make the roundtrip from the intake valve to the piston face (when the piston is close to BDC) and back to the intake valve.

Engine torque at a given rpm is linearly bound to the quantity of air that the engine traps per individual intake stroke, at that rpm. If a factor that influences this quantity of air does so in a manner that is interdependent with rpm, it will influence the overall shape of the torque curve. This is the only means by which a factor can ordinarily have any appreciable influence on the overall shape of the engine torque curve.

The question, of whether piston stroke has appreciable influence on engine torque at low rpm, reduces to the question of whether, for a given cylinder volume displacement and for a given duration of the intake stroke, the volume of air trapped per individual intake stroke is appreciably the same for a cylinder that is long and skinny as it is for a cylinder that is shaped more like a disc.

For most of the intake stroke, the air entering the chamber is trying to catch up with the piston. Sometime before the piston comes to a full stop, the air smacks against the face of the piston and bounces off, then races just as fast, but now moving in the other direction. The amount of air that escapes through the intake valve before it closes depends on several factors, to include the speed at which the air is moving, and the distance it has to travel, and how much time is available, which is different at different rpm. These factors are interdependent. The optimal distance for the air to have to travel depends on the amount of time that is available. For a given amount of time that is available (corresponding to a specific rpm), and for a given cylinder volume displacement, and all else being equal, the quantity of air that gets trapped within the cylinder is different for different bore/stroke ratios.

“You are welcome to believe otherwise, that doesn’t change the facts.”

Alas, the facts are often not in agreement with what one chooses to believe. We all run into this from time to time, so there is nothing to be embarrassed about, unless perhaps the tone you used was unduly assertive.

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By: Jake

Jake — Wed, 04 Apr 2012 19:42:10 +0000

Norm G. says: “…now that the VR is finally being tackled…”

In the “Nothing new under the sun” department: Let us not forget the Matchless Silver Arrow 400cc narrow-angle V-Twins and Silver Hawk 600cc narrow-angle V-4s of the 1930s.

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By: Keith

Keith — Wed, 04 Apr 2012 15:29:40 +0000

Hopefully the Kompressor will be an option…well, one can HOPE.

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By: zuki

zuki — Tue, 03 Apr 2012 19:15:39 +0000

If you wouldn’t go for a motorcycle in this price range over a car if you had the money then you just aren’t a true motorcyclist and just don’t get it… in my opinion! In this price range what would you get? A Civic? How fun! Your bonus is you don’t have to worry about bad weather? Really, how boring! Same rings true with the complaints about the Motus’ price!

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By: zuki

zuki — Tue, 03 Apr 2012 19:08:08 +0000

No Colonel Sanders (Goose), you’re wrong.

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By: Goose

Goose — Tue, 03 Apr 2012 17:21:36 +0000

My point was that bore/ stroke doesn’t effect power out put at a given RPM. You are welcome to believe otherwise, that doesn’t change facts.

Goose

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By: Biker Cat

Biker Cat — Tue, 03 Apr 2012 17:13:35 +0000

I current drive a 2008 VW R32 with the VR6 motor, with 250HP and 245Lbs of torque it’s smooth with that torque down low. I love this motor and it has that rare exhaust note which is music to a motor head. It’s pretty cool someone also loves this motor and designed a motorcycle using this motor. I would like to see a sport touring model with a shaft drive.

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By: Norm G.

Norm G. — Tue, 03 Apr 2012 01:13:25 +0000

re: “the cylinders are “oversquare”, meaning that the bore is greater than the stroke. The cylinders in BMW’s K1600 are just slightly oversquare, and this is the main reason that the engine is as short as it is (“short” in terms of length side-to-side, as opposed to height). This bore/stoke ratio favors engine torque at low rpm, at the expense of engine torque at high rpm, and therefore at the expense of peak power.”

dirck’s statement above is 100% correct as written.

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By: Norm G.

Norm G. — Tue, 03 Apr 2012 00:59:48 +0000

double update, not only is it a “tri-cam”, but like an MV it’s also a “hemi” with a fueling/mercedes 3 valves per cylinder. looks like they gotta whole “multiple of 3″ thing goin’ on. here’s a video of the sound…

http://www.youtube.com/watch?v=YN2zCilUZXk&context=C4020f21ADvjVQa1PpcFMdppUBIOUtK8QFkCDandURz7pYpDSn-9Q=

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