Engines > Your Own Design

V3 90 deg 'Jota' Engine big bore

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AlexS:
Hello there,

What should you do, when you have ideas and make some sketches the last couple of months?
I will start on make a 3d model of a new engine. And later on build it.

A multi cylinder of higher rpm range. More kind of a 'sport' engine.

I do like three, six and even twelve cylinder engines of there sound an simplicity/engine balance. But something different.
But what about a V3 engine? I only know a couple two stroke bikes that use this engine geometry (Honda NS500).


I was thinking of the next thing.

- 3 cylinder 90 degree bank angle
- 180 degree crankshaft. Where cylinder 1 and 3 are on 180 degree, and cylinder 2 shares the crank journal with cylinder 1. (so it is more a mix of a 180 deg twin and 90 deg V twin engine)
- Big bore B/S ratio around 1.4-1.5
- 3 or 4 valve design per cylinder
- Overhead camshaft while cylinder 1 and 3 shares the intake and exhaust camshafts(cam rollers are shifted 180 degrees)
- Split connecting rods with one piece crankshaft, two smaller bearings on each side, a larger bearing in the middle
- Thinking of 2 split crankcase
- Addition, two primary balance shafts for compensate the piston motion of cylinder 2
- Water-cooled
- Larger cam durations than my one cylinder, higher static compression ratio to 1:8-9

Firing order 1-3-2
1 [180 °] 3 [270 °] 2 [270 °]

AlexS:
http://www.youtube.com/watch?v=NQdZDmWgfAg

A rough principle of the bottom block of the V3 engine. Reused some parts and had to modded dimensions.

Art K:
Alex,
That sounds complicated, I'm glad you are visualizing how to make this work & not me.
Art

Admiral_dk:
Hi Alex

The Laverda Jota was a straight 3 cylinder Four Stroke 1000cc with a 180 degree crank for the first six years 1976-1982 and later with a 120 degree crank - is this the one the title refers to ?

Real V3 motorcycles where : 1955 DKW 350, 1968 Suzuki RP68, 1982-1984 Honda NS5000/NSR500, 1983-1984 Honda MVX250F and 1985-1987 Honda NS400R.

A related layout was the W3 engine, although this placed all three cylinders in the same plane, but none of them in the same bank. This was used for the 1905–1915 four-stroke Anzani engine, which was used in motorcycle and aircraft applications.

I have tried to construct something similar to your ideas in Alibre a few years ago, but was never satisfied with the result ....

Best wishes

Per

tghs:
having road a few bikes, laverda jotas were a bit on the thumpy side at lower rpms, but fast and powerful once up to speed, great open road bike.. when BMW K100's came out (4cylinder inline)fast, even power with a harmonic buzz at certain rpms, I thought the electronic gear indicator was one of those "why?" things.. a few years later when the K75 came out (3 cylinder with a counter rotating counter balanced shaft) it was needed as the motor was as smooth as an electric motor,, best triple ever made 

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