1000cc two stroke

[Ixion]

..
On a true V pairs of conrods share the same crank pin

..

Shit load of car and truck V6 and V8 engines that have different ideas.

[Skunk]

They could hardly write "Square four Crank Configuration With Non Parallel banks of Two Cylinders" on the fairing could they?

Just "Square Four" would suffice I think. If it were right that is.
"Isosceles trapezium four" is what you're thinking of - cause square it ain't.

[Ixion]

Firing interval is what would determine if a square four behaved as a V4, two V twins or two parrallel twins or a perverted inline four.

[FilthyLuka]

PS only an inadequate wanker red reps a post because they disagree with it paLuka

hmm "i disapprove..." I disapprove of your outlook on my wee little project, i disapprove of the idea i should just go out and buy a new sports bike and i disapprove of having to tally up the total cost of a build before its starts and spend not a cent more...

I also disapprove of being called an inadequate wanker, hence the red showing said disapproval.

On a true V pairs of conrods share the same crank pin

Wouldn't a two stroke vtwin sharing the same crank pin make it essentially fire like a "big bang" engine? I mean, everytime the piston is at TDC, the spark plug fires and you get a power stroke. So, if two conrods shared the same pin, it would mean both pistons would fire at the same time as they would both be at TDC at the same time, effectively making an expensive single cylinder.

So Aprilia RS, Suzuki RGV and Honda NSR aren't true v-twins...

I suggest you take imdyings advice

[speedpro]

V Engine
One with two banks of in-line cylinders mounted with an angular separation on a common crankcase.

Common crankcase, NOT common crankshaft.

Seems I'm not the only one suffering from a misconception of what constitutes a V configuration engine.

Also direct from the Cagiva website, specifications for the Cagiva C504, as ridden by John Kocinski - "498,3cm3 (56/50,6mm) 80°V4 twin crankshaft". Seems even the dudes designing and building the engines have got it wrong. Just for interest, the cranks in this square four(?) were geared together and contra-rotating.

[xwhatsit]

So, if two conrods shared the same pin, it would mean both pistons would fire at the same time as they would both be at TDC at the same time

Ummm.... no? Not unless the angle between the cylinders was 0 degrees. Which would be hella difficult.

[FilthyLuka]

Ummm.... no? Not unless the angle between the cylinders was 0 degrees. Which would be hella difficult.

#click, brain turns on# oh yeah... Sorry, disregard the post i made before, mind is stuck in single cylinder mode

[speedpro]

Wouldn't a two stroke vtwin sharing the same crank pin make it essentially fire like a "big bang" engine?

No. Plus you can't(shouldn't) build a 2-stroke twin with the cylinders displaced about the crankshaft axis sharing a common crankcase as the cylinder port timings will be different by the value of the V angle. The 1st cylinder whose transfer ports open will get the best shot of air/fuel, leaving not much for the 2nd. You could get away with it if air was force-fed direct to the cylinder ports and not via the crankcase. Pretty typical setup for the BIG turbo diesel 2-strokes as in ships etc. They are in-line engines though.

I've toyed with the idea of supplying fuel/air/oil to a manifold over the transfer ports from a little supercharger I have, but time/ money etc will make sure it never happens.


Edit - I type too slow!

[xwhatsit]

mind is stuck in single cylinder mode

No sweat, I spend my whole life living there

[Ocean1]

mind is stuck in single cylinder mode

No sweat, I spend my whole life living there

Nawt wrong wiv 'em I say. Was good enough for Uncle Sylvester and it's good enough for us.

http://www.motorcyclemuseum.org/classics/bike.asp?id=3

[imdying]

V engines only have one crank - it's a square four.
Do you even know what a square four is?

/edit: Yes, you're right. The sticker on the side is wrong... two pistons going one way, two the other, it's definitely a square four, my mistake. I will try to insure that in the future I do not misinform other members by providing false information in my posts.

[onearmedbandit]

The Fact that it has 2 cranks precludes it from being a true V.........

V engines only have one crank - it's a square four.
Do you even know what a square four is?

I probably owned more two strokes than you ever did, several before you were born,I look forward to their return and vanquish of the four stroke world and I recognise a pointless exercise when I see it

Pixie, just wondering if this helps clear it up a bit for you?

BTW, if it doesn't, let me know because there is an engineer here in CHCH that designed and built a 500cc V4 dual crank ZXR250 based engine. Now this guy has only built and designed engines, and as you have owned lots of engines you no doubt can correct him as well.

[ManDownUnder]

Pixie, just wondering if this helps clear it up a bit for you?

Na mate - that pics got me beat... can you give us a clue... that final shape... not too sure on it.

Rhomboid?

[pete376403]

No. Plus you can't(shouldn't) build a 2-stroke twin with the cylinders displaced about the crankshaft axis sharing a common crankcase as the cylinder port timings will be different by the value of the V angle. The 1st cylinder whose transfer ports open will get the best shot of air/fuel, leaving not much for the 2nd. You could get away with it if air was force-fed direct to the cylinder ports and not via the crankcase. Pretty typical setup for the BIG turbo diesel 2-strokes as in ships etc. They are in-line engines though.!

Nope - two stroke diesels dont have to be in-line. You must have seen GM 6,8 or 12 cylinder two strokes in Vee configuration, eg 6V71 or 8V71.
And as for a naturally aspirated two stroke, whether inline or V, each cylinder has to have it's own crankcase - it might be a common casting but each chamber is sealed from it's neighbour(s)
The main reason for building a V twin over a parallel twin was to get more room in the cylinders for the transfer ports.

[pete376403]

Yeah there is, Detroit Diesels but with no crankcase compression they here big fuck off blowers to get the air into them which brings me to fun fact No 237 2 stroke Detroit Diesel blowers have been turned into superchargers on Top Fuel Dragsters for 50 years.

Detroit Diesel two stroke diesels have four valves per cylinder and IIRC an overhead cam too. (Uniflow design is also used in Nissan UD engines)
The valves are all exhausts and the cam is for the fuel injector (it's been a long time since I had one apart)