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#51 soubriquet

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Posted 11 January 2005 - 07:19

Originally posted by Mark Beckman


Overheating peices of crap they were.


Quite possibly. My first bike had a Villiers 197cc engine. It was my last 2 stroke.

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#52 Mark Beckman

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Posted 11 January 2005 - 14:33

I meant the Ariel Arrow/Leader were peices of crap at least the Villiers went a bit longer but then again zero horsepower doesnt exactly put a strain on anything does it. :lol:

Bad luck if you came to a hill :rolleyes:

Come to think of it there isnt a single British 2 stroke worth using as a boat anchor and dont anyone come back with Starmaker cause they were peices of crap too.

Served them right for putting up with 146 year old Lord (insert name such as Smyth-Bradford ect)'s running the board.

"its been running fine for the last 35 years and I see no reason to update it now, those little Asian scooters are just a fad, we make the real motorcycles...."

#53 VAR1016

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Posted 11 January 2005 - 15:58

Originally posted by Mark Beckman
:

...Come to think of it there isnt a single British 2 stroke worth using as a boat anchor and dont anyone come back with Starmaker cause they were peices of crap too...


Surely you are not including the Scott "Flying Squirrel" in this generalisation?

PdeRL

#54 thomaskomm

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Posted 11 January 2005 - 19:39

Originally posted by indigoid
for me, BRM's supercharged 1.6 (or is it 1.5?) litre V16 takes the biscuit. sounds incredible, too! IIRC 370-420 bhp at around 11500rpm, depending on what book you are reading


Hello this hell of car generate over 550 HP!

Thomas

#55 malbear

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Posted 12 January 2005 - 07:00

[QUOTE]Originally posted by vivian



A flat engine. Two pistons share the same bore, so we have two crank cases. There is no cylinder head, the two pistons work against each other.



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There is a similar engine that has been raced . It has replacement heads with a smaller half speed opposed piston.
http://www.jack-brabham-engines.com/

Engine Type Air-cooled opposed-piston rotary- & reed-valve 90° V-twin
Bore x stroke 86 x 57 lower, 60 x 25 upper
Capacity 616cc intake, 575cc compression corrected, 643cc expansion corrected, 592cc exhaust.
616cc intake, 756cc compression, 732cc expansion, 592 cc exhaust
Measurements taken with upper crankshaft 20° retarded
Corrected measurements taken after ports are closed.
Compression ratio 10.6 : 1 (approx)
Fueling 4 x 35mm Mikuni CV carburettors
Ignition Dual ignition, Ducati CDI & two H-D 12 volt coils
Power 40 bhp at the rear wheel at 5000rpm as tested after Sir Alan Cathcart's test ride. (Computer predicts 86bhp @9000rpm, 41 ft/lb @ 6000rpm)
Valve timing Intake open 20° BBDC 520° close 60° ABDC 240°
Duration 440° (this is not a mistake)
Maximum port area at 20° ATDC
Exhaust open 40° BBDC 500° close 60° ATDC 60°
Duration 280°
Maximum port area at TDC 0°
Overlap 260° (also not a mistake)
The reed valves control the beginning of intake according to engine demand.

MOTO GP RULES
To help keep a cap on power and, hence, speed, the MSMA has decided to propose a reduction in engine capacity from 990cc to 900cc. "The intention is not to reduce performance but to prevent a continuous improvement in speed and lap times," according to the press release.

2004 2007 weight changes
2 Cylinders 135 Kg 133Kg - -2Kg
3 Cylinders 135Kg 140.5 Kg +5.5Kg
4 cylinders 145 Kg 148Kg + 3Kg
5 cylinders 145Kg 155.5 Kg +10.5 Kg
6 cylinders 155Kg 163 Kg +8Kg






The proposed changes to the rules also affect the minimum weight standards, adding more weight to engines with more than two cylinders from 2007.


The proposed changes above may indicate the technical direction that some manufacturers are pursuing for the future. As Honda is the most powerful voice among the companies, it is interesting that the proposed minimum weight for five-cylinder machines, such as the Honda RC211V (and Proton KRV5), has been increased the greatest amount. This may indicate that Big Red is already working on new engine configurations and is looking to abandon the V-5.

And, as two-cylinder bikes are the only ones to get a minimum weight decrease, might we see the introduction of a 900cc MotoGP V-Twin? If so, it wouldn't be as powerful, no doubt, but it would enjoy nearly a 50-pound weight advantage over a V-5-powered machine. And, as a Twin would have a 66-pound advantage over a six-cylinder-powered bike, it looks like the rumors of a Honda V-6 will not be fulfilled.

The MSMA is also looking at perhaps reducing the 2005 rule for a 22-liter fuel tank capacity (down 2 liters from current rules) for the 2007 season.

The introduction of 4-stroke machines to MotoGP has resulted in a huge amount of newfound interest in the class. Now, with revised regulations again on the table, the series might get even more interesting.


The Testastretta engine fitted to the Ducati 998R 2002 version, the bore is 104 mm.
Unfortunately, such a large bore currently causes combustion problems with dramatically decreased efficiency.
This stems fundamentally from the need to augment the injection advance and from the worsening of the "shape factor" of the combustion chamber which, with the reduction of the bore/stroke ratio, becomes ever broader and flatter. The "shape factor" is a critical synthetic value to check a combustion chamber's good operation, and a good indicator of its compactness and "thermal efficiency".
It should be borne in mind that aspirated racing engines require rather extreme valve lift and overlap angles, therefore, cavities are made in the piston crowns to prevent contact with the half-open valves. The combustion chamber is therefore practically contained in the piston cavities, such cavities becoming bigger as the stroke/bore ratio decreases, which makes it hard to obtain the high compression ratios required by high specific power engines.

The Beare sixstroke does not have these limitations because the main lower piston does not have valve cutouts and the combustion chamber is a compact design with squish contribution from both upper and lower pistons. The shape is much more like a fist than a flat hand hence thermal efficiency is high .
Combustion chamber diameter oprox 75mm
The main piston is lighter and stronger than the 4-stroke, because the lack of cutouts allow a thinner slightly domed top
Malcolm does believe that the sixstroke 15kg weight advantage will be a major benefit for the Beare Sixstroke, much more so than the 30kg handicap enjoyed by Twins in 500cc twostroke racing. "Working on the assumption that all these four-strokes are going to make enough horsepower, 15 kilos is a lot," he says. It’s straightforward enough, the Twins will have a 10 percent weight advantage and force equals mass times acceleration, so it is a big difference.


Sixstroke Beare 900cc Vtwin MOTO GP

Bore 116.25 mm stroke 42.5 upper bore 82mm upper stroke 34mm
compression ratio 12.25 to 1
power 337HP @ 15000 RPM
torque 74.6Ft/Lbs x80% x2 = 118Ft /Lbs
piston speed at 18000 is 5019 Ft/min or 25.4965 Mtre / sec
XL engine file
Torque 101.2 NM or 74.6 Ft /Lbs discount by 20% and multiply by 2 for twin cylinder is 118 FT/ Lbs
6 port design with 3 exhaust ports leading to a rotary disk, 3 intake ports,One intake rotary disk and 2 reed valves with air assisted injectors. 2 or 4 10mm plugs per cylinder.
The port area is oprox 20% to 30% more than a 4 valve head
Results of XL file sixstroke touque calculator

Based on Dual Cycle
Total Torque
Fourstroke 62.00

Main Top
66.05 35.15 101.20

Increase in torque 63.23%

#56 Bill Sherwood

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Posted 13 January 2005 - 13:24

Originally posted by malbear A flat engine. Two pistons share the same bore, so we have two crank cases. There is no cylinder head, the two pistons work against each other. [/B]



Seen this engine in person and it's VERY impressive.
Very clean, very torqey.

#57 Mark Beckman

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Posted 13 January 2005 - 15:33

Originally posted by VAR1016


Surely you are not including the Scott "Flying Squirrel" in this generalisation?

PdeRL


Reasonable enough bike for its time if you could afford one, but trying to reintroduce it in the 70's ? (The Silk) :rotfl:

#58 VAR1016

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Posted 13 January 2005 - 18:38

Originally posted by Mark Beckman


Reasonable enough bike for its time if you could afford one, but trying to reintroduce it in the 70's ? (The Silk) :rotfl:


You could still order a new Scott in the 1960s; price was about the same as a Triumph or Beezer 650.

pdeRL

#59 McGuire

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Posted 14 January 2005 - 10:43

Does anyone know what became of the Britten? What a brilliant and creative guy RIP.

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#60 McGuire

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Posted 14 January 2005 - 10:46

Originally posted by indigoid
for me, BRM's supercharged 1.6 (or is it 1.5?) litre V16 takes the biscuit. sounds incredible, too! IIRC 370-420 bhp at around 11500rpm, depending on what book you are reading


Yes, but did it ever actually perform 11,500 revolutions in a row? :D

#61 Wuzak

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Posted 14 January 2005 - 12:22

Originally posted by McGuire
Does anyone know what became of the Britten? What a brilliant and creative guy RIP.


http://www.britten.co.nz/

I think the company pretty much stopped after Britten died.

Pity, because the current MotoGP rules would have enabled him to enter one of his fantastic creations.

#62 jgm

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Posted 17 January 2005 - 16:17

www.bigbikeriders.com/48cyl.htm

Not a racing engine but a 48 cylinder motorcycle is good for a laugh.

#63 ciaoduc1

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Posted 21 January 2005 - 08:17

Not exactly meant for 2 or 4 wheeler racing but pretty crazy just the same...9 four cylinders on a single crankshaft.
http://www.prime-mov...ges/xr7755b.jpg

This guy and his "model" of an engine should also be worthy of mention...sorry to bring another deltic into the discussion.
http://www.craftsman...m/Tomlinson.htm

#64 McGuire

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Posted 29 January 2005 - 12:43

Originally posted by soubriquet


They look as if they may be Ariel Arrow/Leader barrels and heads. They were considered quite advanced for their time, and much better than anything by Villiers.

Cheers
S


Hey, good eye. You know your stuff. Thanks for the info...one more piece of another puzzle.

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#65 llmaurice

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Posted 30 January 2005 - 13:58

Just consider for a moment that the current 125GP engines (single cylinder ) can produce over 50 brake and 250gp (twins) around 98 at around 14000rpm! using 102 octane U'leaded
Look at the bhp/litre and then we see why the faithful simple two stroke still cuts the mustard (400bhp per litre ) Match that with F1 !

#66 Mark Beckman

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Posted 31 January 2005 - 15:48

Originally posted by llmaurice
Just consider for a moment that the current 125GP engines (single cylinder ) can produce over 50 brake and 250gp (twins) around 98 at around 14000rpm! using 102 octane U'leaded
Look at the bhp/litre and then we see why the faithful simple two stroke still cuts the mustard (400bhp per litre ) Match that with F1 !


As the individual cylinder size increases for a 2 stroke the efficiency drops quite dramatically.

A 300cc 4stroke F1 currently gets 80hp (maybe 70hp+ as a single) a target a 300cc 2 stroke could not acheive and even if it did the fuel consumption would be way over the 4 stroke.

In the Supermono classes in Australia, 650cc 4 stroke singles leave 540cc 2 strokes for dead.

#67 djellison

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Posted 31 January 2005 - 16:02

Originally posted by McGuire


I don't know anything about it either. A friend sent me the photo...I believe the engine is in a British collection (Donington?).


Yup - that's at Donington - it MIGHT be a Porsche project - or perhaps thats just my brain trying to link it to a part-restored Porsche from the late '60s in the same 'wing' of the collection.

There's a lot of engines at Doni - I'd submit that the DFV was fairly crazy. Imagine an engine built today that would still, if slightly derived over time, power modern F1 cars in 2025. It's an impossible thought - yet that's what happened when the DFV appeared.

Doug

#68 Superliner II

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Posted 31 January 2005 - 18:30

Originally posted by Mark Beckman


As the individual cylinder size increases for a 2 stroke the efficiency drops quite dramatically.

A 300cc 4stroke F1 currently gets 80hp (maybe 70hp+ as a single) a target a 300cc 2 stroke could not acheive and even if it did the fuel consumption would be way over the 4 stroke.

In the Supermono classes in Australia, 650cc 4 stroke singles leave 540cc 2 strokes for dead.


But a 500cc V4 two stroke can still produce about 200hp. Big cylinders do not equal big power. The big single cylinder (250cc+) conventional two strokes can suffer from poor scavenging though. Old fuel consumption and emissions problems have been solved by the latest generation of fuel injected outboards and snowmobile engines. Two strokes can still deliver higher specific power from a lower weight package than any four stroke engine.

#69 Engineguy

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Posted 31 January 2005 - 19:22

Originally posted by Superliner II

But a 500cc V4 two stroke can still produce about 200hp. Big cylinders do not equal big power. The big single cylinder (250cc+) conventional two strokes can suffer from poor scavenging though. Old fuel consumption and emissions problems have been solved by the latest generation of fuel injected outboards and snowmobile engines. Two strokes can still deliver higher specific power from a lower weight package than any four stroke engine.


Looking at it from an F1 standpoint (this is Atlas F1 after all :) ), if you just allow 3.0L normally aspirated engines... and no other restrictions... a V12 four stroke would go to "about" 1200 HP (Honda claimed to be exceeding 1000 HP by the end of 2004 with a V10) and weigh about 100kg.

Stacking 6 of your example 500cc V4 modules that make "about" 200 HP each gives you a V24 with the same 1200 HP... I hate to even think about the mass and bulk of all those expansion chambers... and you'd need center power takeoff (anyone remember the Heidegger 1.5L inline six turbo F1 engine?) which complicates packaging too.

Make mine four stroke.

#70 llmaurice

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Posted 31 January 2005 - 20:35

All those great old lumps of metal hurtling about and needing 4 engine cycles to produce a bang !
Interestingly in Europe ,the single cylinder brigade (Monos) have banned two strokes to allow the great tractor engines they call supermonos to stay competitive yet in Motocross , the move is back to 2 strokes again because of the weight and ponderance of the 4 strokes .
We could always of course reverse the equation of say power output of 8*125 Gp motors and
Think what power a 125 4 stroke single would produce with cams /followers/valves and all the rest . Certainly not 50 brake ,thats for sure .

#71 llmaurice

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Posted 31 January 2005 - 20:39

Sorry , I didn't realise we can only talk about F1 here . I'll get me coat !

#72 Engineguy

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Posted 31 January 2005 - 22:03

Originally posted by llmaurice
Sorry , I didn't realise we can only talk about F1 here . I'll get me coat !


I certainly didn't say that.

My point was that two strokes are not inherently more powerful or a better solution for a given task. Due to bore size effect on breathing area, at some point above 125cc/cyl two strokes make less specific power... at some point below 250cc/cyl four strokes make less specific power. Somewhere there is a practical crossover point. I can't get excited enough about a disappearing type of engine to put much more thought into them. Besides, the sound is annoying.

Granted, ignoring upcoming emissions requirements that will apply to all engines, two strokes may be a better fit for model airplanes, weed-wackers, and shrill kiddie motorscooters. Just kidding; I have ridden a 500cc V4 two stroke, so I know first hand what kind of peak power they make... but it was so peaky (rubber-bandy? explosive?) it wasn't fun, just scarey. Of course I'm no Kenny Roberts...

#73 Superliner II

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Posted 31 January 2005 - 22:48

The need for bulky expansion chambers can be eliminated by use of a crank driven compressor as in those enormous 2 stroke diesels that power most of the worlds ships and quite a few locomotives.

You are forgetting something. You only need a 1200 hp 4 stroke engine to haul all that unnecessary and wasteful weight around. 4 stroke engines produce pitiful bhp/ton figures that make me laugh at sarcastic trogs with their heads stuck in the sand when it comes to 2 stroke Vs 4 stroke power plants. Only kidding ;)

Its all about the numbers in racing and you have to admit they have always looked pretty bad for the 4 stroke.

#74 Engineguy

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Posted 31 January 2005 - 23:50

Originally posted by Superliner II
The need for bulky expansion chambers can be eliminated by use of a crank driven compressor as in those enormous 2 stroke diesels that power most of the worlds ships and quite a few locomotives.

If we're going to add crank driven compressors to the party our 3.0L four stroke is going make 2000 HP. :lol:


Originally posted by Superliner II
You are forgetting something. You only need a 1200 hp 4 stroke engine to haul all that unnecessary and wasteful weight around. 4 stroke engines produce pitiful bhp/ton figures that make me laugh at sarcastic trogs with their heads stuck in the sand when it comes to 2 stroke Vs 4 stroke power plants. Only kidding ;)

Its all about the numbers in racing and you have to admit they have always looked pretty bad for the 4 stroke.


The 3.0L V12 four stroke would make 11,000 BHP/ton. To match that your 500cc V4 two stroke has to weigh 37 lbs (under 17kg). Does it?

#75 hydra

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Posted 01 February 2005 - 13:14

How about a dual stage supercharged/turbocharged sleeve valve 2-stroke running ~18psi boost with a BMEP of 250-300 (500-600) psi and a BSFC of ~0.34-0.37 (according to Ricardo)? Now that's the shiznit right there!;)

#76 Superliner II

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Posted 01 February 2005 - 14:03

Obviously not.

I would guess that a conventional 180bhp (I wasn't sure before so I checked the the facts) 500cc GP engine would weigh between 45 and 55 KG (average 356bhp/ton) My 250cc 65bhp engine weighs 30 kg (216bhp/ton). My 125cc 28bhp direct drive kart engine weighs 15kg (186bhp/ton) and my 100cc 30bhp direct drive kart engine weighs 10kg (300bhp/ton). My 27cc go-ped engine with pipe produces 5bhp from a package that wieghs less than 2 kilos. Its a little monster though! Show me some four stroke motors that can compare cylinder capacity-wise.

They are a lot cheaper to manufacture and easier to fix too. There will always be a need for this type of power plant whether it be in marine, industrial, locomotive, home or racing applications whatever technology is used to bring it up to date with emissions regulations. Yes they are noisy but some of us like them. My 100cc kart engines rev to 18000+rpm. Just like an F1 car. Now you can't say that isn't exciting when a pack of either of them are racing to the first corner.

Getting back to crazy racing engines, I am currently working on modeling a 1997 Yamaha TZ 250cc GP engine on Ricardo WAVE. The interesting thing about this engine is the exhaust water injection system. The water has a cooling effect on the exhaust gasses as they leave the cylinder thereby slowing down the pressure waves in the expansion chamber. The main effect this has is to quite dramatically increase hp throughout the revs, effectively softening the peaky nature of these engines. Much easier to ride and can accelerate/carry more corner speed than almost any 600cc machine. However peak hp is at approx 800rpm less and is 2hp down on the same engine with the water injection switched off. There is just a lot more area under the power curve. My aim with the WAVE program is to try and get back peak power and over rev hopefully by using the right combination of different expansion chamber design and modified exhaust port/power valve timing.

This system was also used on Hondas 500cc gp machines in the late 90's. Doohan didn't like the feel of it so like many other good ideas in engines it never got the development it deserved.

I like the sound, power, feel and reliability of four stroke as much as the next bloke but when it comes to my racing I can afford a lot more fun in a variety of different types of racing from hill climbs to off road to circuit racing with two stroke power.

Just my preference Engineguy. Don't shoot me for it :confused:

#77 Flatoutincanada

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Posted 01 February 2005 - 14:24

Hey everyone! I just regisstered and started reading this thread about 2stroke vs 4strokes. Typically in all forms of racing 4strokes are given a displacement advantage to be competitive. Usually a 600 cc snowmobile 2stroke class will allow 1000cc 4 strokes in. In the Moto GP motorcycle class 500cc 2strokes compete with 900 cc 4strokes. 2-Strokes in the smaller engine sizes are definitely higher output per cc and per kilogram than 4-strokes. It is only when you get in the bigger ( 1litre and up) engine sizes that 4-strokes become more favourable for racing. As for saying that the sound of a 2stroke is annoying is like saying that skinny women are ugly! Beauty is in the eye (or the ear) of the beholder! I personally love a 2-stroke at full song but I am bias cause I build the exhaust pipes for racing two strokes. www.gifford.ca

#78 Mark Beckman

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Posted 01 February 2005 - 15:49

Originally posted by llmaurice


Think what power a 125 4 stroke single would produce with cams /followers/valves and all the rest . Certainly not 50 brake ,thats for sure .




And a 125 2 stroke makes even less by itself.

It needs the aid of a (rather bulky) reflective wave supercharger to produce the power they do.

#79 llmaurice

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Posted 01 February 2005 - 16:02

Show me a 50 brake normally aspirated 125 single 4 stroke and I show you ------
--------- my wallet !

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#80 Mark Beckman

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Posted 01 February 2005 - 16:03

Originally posted by Flatoutincanada
. In the Moto GP motorcycle class 500cc 2strokes compete with 900 cc 4strokes.. www.gifford.ca


No they are allowed to race in the same class (with lighter weight too) but "compete" is certainly the wrong word to use ;)

The 2 strokes are peaked (no pun) at 195 hp but the 4 strokes can get 280+ hp but unridable at the moment and I beleive (depending who you talk to) they race with around 230-240 hp.

Sure the smaller 2 stroke makes HP but other than the recreational/grasscutting world whats their place ?

Certainly not in the USA !!

#81 Superliner II

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Posted 01 February 2005 - 16:54

Large capacity injected 2 stroke jet skis are still passing emissions regs in California last I heard so they can't be that bad.

Mark, other than recreation, two stroke has a place where high specific power and low weight are absolutly necessary such as ocean going tankers and in locomotives. I'm sure you know of the Orbital company. The advantages are clear and the technology is in place. Now all its going to take is to convince Joe and Mary Schmo to give something new a try when they buy a new car.

#82 Flatoutincanada

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Posted 01 February 2005 - 18:42

Mark Beckman! Exactly my point. More power per cc can be extracted from a two stroke than a 4stroke. Otherwise a class would not give 4strokes a displacement advantage. A 500 cc 4stroke would be lapped several times in a race by a 500cc 2stroke regardless of state of tune. As for emissions in USA or anywhere else in the world, two strokes can be (and are currently being built) to meet any emission standard in place. Racing engines (recreational or not) have never regulated emissions as far as I know. Direct injection or semi-direct injection not only solves the emission problem but also increases fuel efficiency to that of comparable 4strokes with little effect on performance.
Also when you look at the vast amount of hazardous waste oil being generated by 4 strokes and the extra cost and complexity of manufacture, 2 strokes are an attractive alternative to the old faithful 4 stroker environmentally speaking. They also sound better : :clap:

#83 llmaurice

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Posted 01 February 2005 - 19:19

Fortunately Mark ,the world isn't just the USA (just as well as we'd be under water by now with all that melted ice ) And 2 stroke motors are alive and well still in most of our "lesser" nations . As regards the 195 BHP ceiling on 2 strokes ,the main reason for the hp capping was the rubber situation and the fact that very few riders could handle the optimum power they produced because of way it was delivered hence the terrible "big bang " misnomer . If development had continued .we would see further gains still !

#84 desmo

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Posted 01 February 2005 - 19:24

Originally posted by Mark Beckman




And a 125 2 stroke makes even less by itself.

It needs the aid of a (rather bulky) reflective wave supercharger to produce the power they do.


Wouldn't any exhaust or intake plumbing that would increase the VE of an engine above that of an engine with no exhaust system and just an injector into an open intake port be supercharged then by that rationale? If an expansion chamber is a "supercharger" (and it sort of is in a sense, I suppose) aren't all engines supercharged?

#85 Mark Beckman

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Posted 02 February 2005 - 11:47

Originally posted by desmo


Wouldn't any exhaust or intake plumbing that would increase the VE of an engine above that of an engine with no exhaust system and just an injector into an open intake port be supercharged then by that rationale? If an expansion chamber is a "supercharger" (and it sort of is in a sense, I suppose) aren't all engines supercharged?


Of course only a fool would argue your point but in the case of an expansion chamber on a 2stroke, it must be considered an entity to itself when considering not only that it is responsable for doubling the efficiency but also its sheer bulk and difficulty of packaging and without it a 2 stroke is useless efficency wise.

I suggest that I could mechanically supercharge our theoretical 125 4stroke within the same packaging confines and achieve 50 hp.

Its only that you Guys are staying within common racing regulations thinking in regards to supercharging and manafacturers costing/profit bias towards 2 strokes that you are basing your comparisons on.

In the world of motocross 99 out of 100 open class bikes sold are now 4 stroke, was the opposite for the last 30 years.

#86 Mark Beckman

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Posted 02 February 2005 - 11:58

Originally posted by Superliner II
Large capacity injected 2 stroke jet skis are still passing emissions regs in California last I heard so they can't be that bad.

Mark, other than recreation, two stroke has a place where high specific power and low weight are absolutly necessary such as ocean going tankers and in locomotives. I'm sure you know of the Orbital company. The advantages are clear and the technology is in place. Now all its going to take is to convince Joe and Mary Schmo to give something new a try when they buy a new car.


I notice Yamaha have slotted an R1 motor into jetskis too, the 4 strokes are coming ! (probably others too but I dont really follow them)

Yes I've even met Ralph Sarich, I was pretty young and he had a revolving cutaway at the Melbourne motor show (the actual original orbital engine!) and have read his deeds for the last 30 years.

I'd like to know if the huge 2 strokes are positive displacemently supercharged and what fuel do they use ?

#87 Mark Beckman

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Posted 02 February 2005 - 12:18

Originally posted by llmaurice
Fortunately Mark ,the world isn't just the USA (just as well as we'd be under water by now with all that melted ice ) And 2 stroke motors are alive and well still in most of our "lesser" nations . As regards the 195 BHP ceiling on 2 strokes ,the main reason for the hp capping was the rubber situation and the fact that very few riders could handle the optimum power they produced because of way it was delivered hence the terrible "big bang " misnomer . If development had continued .we would see further gains still !


I'm confused....

a. The USA is moving away from and banning 2 strokes to clean their air.

b. Garden variety 2 strokes in their millions are responsable for staggering amounts of air pollution in our lesser nations and contributing to 'melting ice'.

c. Honda saw 202 hp from one 500 and said that was it no more to be found, their quote not mine.
d. The big bang was a specific type of firing order 500 2 stroke that had 10 less hp but better ridability

Honda, Yamaha and Suzuki the combined largest producers of 2 strokes in the world are the ones who pushed for 4 strokes for MotoGP, its a changing world, why flog a dead horse ?

I am moving to Chongqing, China on Friday (4th Feb), one thing I'm not looking forward to is the smog and smell from squillions of 2 strokes running around.



#88 llmaurice

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Posted 02 February 2005 - 13:27

You'll be pleased to know that the Chinese Government are banning the manufacture of 2 stroke bike engines then. No doubt they'll follow the "enlightened" lead and force ctalyasts on to their populace so their emissions will increase CO2 to something approaching 16% from 14%
Whos bright idea were catalysts ? Not the Japs , nor Ford I suspect who already had lean burn.
Its interesting to see that even Dorna have bowed to the mighty dollar and are permitting the Laguna Seca event to run without 250/125s so its not really a full Grand Prix just a local selling gimmick for the big 4 (plus the ODD Italian machine etc. )

#89 McGuire

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Posted 02 February 2005 - 21:57

With a power stroke every crankshaft rotation, the two-stroke engine can achieve twice the operating inefficiency of the conventional four-stroke design. :D

#90 Greg Locock

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Posted 02 February 2005 - 22:35

Mark, Lovely Chongquing, the jewel of the Gorges.

How long are you in for?

#91 BRIAN GLOVER

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Posted 03 February 2005 - 02:14

Place an ice cube in a glass and fill it to the brim with water. Return in an hour or so and you will observe the water level to be below the brim, you communist you.
The most accurate records of the climate in the last 60 years are held by the US Navy. There are 5000, 10000, 30000 and 50000 year cycles in the earth's climate and to claim that the earth is warming in the past 100, 200 or 300 years is absurd. The scientist that proclaim this have to be alarmists to get funding, or commies like you.
A bunch of scientists at the University of Victoria in BC Canada lead a group of international scientists who happen to be in the majority, conclude that their is no evidence of global warming despite winters over the last decade getting colder and longer in duration.
Why, right here in Florida, we had the coldest winter since 1940 last year and Siberia was the coldest in 100 years.
The ice caps never change their volume. Only the relationship between the sun and the earth change the climate due to their molten cores and the variation of polarity therein. Some short term climate changes occur with volcanoes and meteorites, etc.
The rain forests spew out more CO2 than all of industry. Get rid of them and all the miserable creatures that live in them. Mankind has no influence on the climate. The Kyoto Protocol is to destroy capitalism and hydrogen will cause more harm to the atmosphere than any amount of C02.
Sides, you would be speaking German if it whereat for us.


Originally posted by llmaurice
Fortunately Mark ,the world isn't just the USA (just as well as we'd be under water by now with all that melted ice ) And 2 stroke motors are alive and well still in most of our "lesser" nations . As regards the 195 BHP ceiling on 2 strokes ,the main reason for the hp capping was the rubber situation and the fact that very few riders could handle the optimum power they produced because of way it was delivered hence the terrible "big bang " misnomer . If development had continued .we would see further gains still !



#92 Ray Bell

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Posted 03 February 2005 - 03:37

Originally posted by BRIAN GLOVER
.....right here in Florida, we had the coldest winter since 1940 last year and Siberia was the coldest in 100 years.....


Right on... sez it all, doesn't it?

There was always a time it was either colder or hotter, and always that's in the last fifty or hundred years!

If there was a time that was just as hot or just as cold, then things are going on like they always did... simple logic.

But how does rainforest produce carbon dioxide? I thought plants ate it up and gave us oxygen...

#93 llmaurice

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Posted 03 February 2005 - 09:51

I realise that we are moving away from the real topic but if mankind has no real effect on the evironment where did all the CFCs come from that have put the hole in the heavy side layer , not from the need to have air con I presume ?
As the song goes "When will they ever learn ? "

#94 hydra

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Posted 03 February 2005 - 11:43

Originally posted by Superliner II
Obviously not.



Yeah? Why not? :rolleyes:

#95 Mark Beckman

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Posted 03 February 2005 - 13:04

Originally posted by McGuire
With a power stroke every crankshaft rotation, the two-stroke engine can achieve twice the operating inefficiency of the conventional four-stroke design. :D


Iguess...

if there wern't BLOODY BIG HOLES in the sides a 1/4 the way down the bore :lol:

(thats redneck tech talk there)

#96 Mark Beckman

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Posted 03 February 2005 - 13:16

Originally posted by Greg Locock
Mark, Lovely Chongquing, the jewel of the Gorges.

How long are you in for?


At least a year Greg.

We (my wife and daughter) plan to cruise down the Yangtzee, see the pottery warriors, the panda's ect their all within range of Chongqing.

First time out of Australia so the culture shock will be the first battle, luckily we have friends and a 'Western' social group to go to there as well as arriving there with 3 other Aussies.

I'll post any weird mechanical contraptions I come across (most likely on the opposite end of the scale from F1 though!) and I will be looking ;)

#97 Mark Beckman

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Posted 03 February 2005 - 13:18

Originally posted by McGuire
With a power stroke every crankshaft rotation, the two-stroke engine can achieve twice the operating inefficiency of the conventional four-stroke design. :D


Sorry, I just read the post properly :rotfl:

#98 Engineguy

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Posted 03 February 2005 - 16:29

Originally posted by Mark Beckman


Sorry, I just read the post properly :rotfl:


Glad you misread it (so did I... surprised me McGuire bluntly would say what I thought he said).

Otherwise I wouldn't have got to have a good chuckle at your bloody big hole statement.

And now I get to have another good chuckle now at what he really said :rotfl:

#99 McGuire

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Posted 04 February 2005 - 11:29

Originally posted by Mark Beckman


Sorry, I just read the post properly :rotfl:


Quite all right. Folks often don't get the half of what I am going on about. It's more fun that way. :D

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#100 Wuzak

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Posted 04 February 2005 - 12:12

Originally posted by Ray Bell


Right on... sez it all, doesn't it?

There was always a time it was either colder or hotter, and always that's in the last fifty or hundred years!

If there was a time that was just as hot or just as cold, then things are going on like they always did... simple logic.

But how does rainforest produce carbon dioxide? I thought plants ate it up and gave us oxygen...


Some plants give out carbon dioxide as well as oxygen. I believe that they expire oxygen during the day, inhaling carbon dioxide, and vice versa at night!