Girls/Women and Bikes?

[ScotsLass]

[ScotsLass]

Hmm, so it seems.

147,373 registered motorcycles in Denmark in 2010. Population estimate 5,671,050 in 2011 = .026 motorcycles per capita.


1,300,000 registered motorcycles in the UK in 2010 versus 63,300,00 people in 2010 = .0205 motorcycles per capita.[/quote]

Lol, I might have guessed you would have produced figure to prove a case.....nice one.
The other statistic I noticed when over there had been the shocking level of deaths relating to motorbikes, with 13 people dead in what seemed at the time like a really short period to me.
Are the Brits having a similar level here, or are we better at not getting killed?

[SuziCat]

[bazza]

[Rogerborg]

[Polarbear]

Roger, next time think before you post what you have dug up. It might not be true, but more to the point, it won't encourage the pond life on here to keep on with the booring so called huimourous shit thats gone on for 10 pages or so.
____________________
Triumph Trophy Launch Edition

[Dragonfly]

I wouldnt worry about one of two eejits commenting in this thread the important people who are talking to you are worth knowing and proper gentlemen.
____________________
All the breast.
Muzza on Binge:
He's too busy beating the everloving shit out of Lizzie to notice this thread has taken a turn down Drama Avenue and stopped off at the popcorn shop.

[ScotsLass]

Oi - are you slagging off my lovely old timer - you sarky monkey you

It's a joy to ride and reminds of my holidays back in the mid 80's. Nowt wrong with that !![/quote]

Yeah I was rather fond of the 80's as well, although being young and not knowing what the future held did help to make it even more fun.
I even remember doing weekends in Blackpool with friends, and having a fab time. I tried a weekend there about 5 years ago and hated it............must be a getting older thing

[Teflon-Mike]

[ScotsLass]

[ScotsLass]

Well, the 'history' of the two-stroke goes back to the pioneering era; some of Benz early engines were proto-two strokes.
First two-stroke to make a 'spash' in biking though was in 1908, made by Angus Scott... parallel twin, water cooled, with two-speed gear-box, all chain drive, telescopic forks, a kick-start and NO pedals.

It debuted at a Hill-Climb and was almist imedietly 'Banned' by dint of the gear-box, and then the lack of pedals, and ultimately by its two stroke engine.

Angus apparently sat cool-lee on the start line astride his machine smoking a pipe, as fellow competitors were gioven the flag to start, and ran along side or pedaleed furiousely to start thier machines and get going, then struggled up the hill, having to stop half way to swap drive belt pulleys, and then again at teh top to swap back again...
Then when Angus's turn came along; he tapped out his pipe, popped it in his top pocket, unhurredly put his goggloed down, and without getting out of the saddle, kicks started the engine, and pulled away, and effortlessly glided up the hill without stopping...
Or so the legend says!

It was a very advanced motorcycle, and Angus Scott was the architypal boffin; and as soon as he had seen his creation 'proven' went off in search of new technical challenges, his bikes built by the Jowwet Company in Shipley Yorkshire, under licence.
However... through the 1920's & 30's, the four stroke proved its superiority for reliability, and performance.
The two stroke was relegated to the boffins who ponder the inherent problems of 'porting'.

A two stroke, uses the underside of the piston rising in teh crank case to suck charge into the engine, and falling again, to squash it into the top of the cylinder, to save one of teh four strokes of the four-stroke engine; but to save the exhaust stroke, exhaust gasses are merely 'vented' from holes in the cylinder wall, uncovered when the piston is at near bottom dead centre; the last remnants washed out of the cylinder by the fresh charge being squashed in from teh crank case.

FIRST fundemental problem of the two stroke, is when charge has been sucked IN to teh crank-case, by the piston rising, NOT letting it get squashed back out again as it falls.

This is called 'Trapping Efficiency' and in thoery, with no kind of valving to hold charge in the crank-case, OUGHT to all be pumped back out again!

The conventional 'piston-ported' two-stroke uses holes in teh piston skirt passing ports in the cylinder wall, so that the piston rides causing a vacuum, sucks in a wallop load of charge, then close again before they get squashed.

This does NOT trap a lot of charge, and limits the power potential of the engine; a 125cc piston ported engine might only actually 'trap' 50cc or less of charge; but firing twice as often, will burn 100cc of charge in the same crank revolutions as a four stroke, 125, that 'could' suck a full cylinder-full of charge in.

The next problem, is that a four-stroke engine can have a 'wet' crank-case; oil spashing around in it, lubricating the crank bearings, cylinder walls & con-rod bearings. A Two-Stroke, dragging teh charge through the crank-case, has to be 'dry' or it would get splashed up into the ports, and be burned with the charge. BUT still needs lubrication, hence 'some' oil is pumped into teh crank-case or fed in with the fuel, on a 'total-loss' principle, limiting teh amount of oil that can be burned. BUT with the bearings still needing lubrication, and unable to be provided with possitive 'forced' lubrication like a four-stroke, they have to have 'open' roller bearings that cant take as much load, as the plain bearings used in most modern four-strokes.

THIS is one of the fundemental problems the two stroke engine STILL suffers; the burning oil, is condemned by emmission controls, while the necessary bearings that can tolerate such low lubrication, cant tolerate such high loadings; making bearings bigger to take higher loads, means making them heavier, increasing their own loads and deminishing any gain from them.

Then above thee cylinder, we have the 'nigle' of this missing induction & exhaust stroke. In a four stroke engine, you have an entire half crank revolution to suck charge into the cylinder, and another half revolution to push the burned gasses back out. On a two stroke, you have only a brief maybe 90 degree of crank rotation period, when the piston is near the bottom of teh stroke, to do BOTH. Pump charge in, and get exhaust gas out. One of the reasons that while people mutter about 'revvy' strokers, actually they rarely turn as many crank rpm as four strokes! Faster teh crank turns, shorter in time that small window of intake & discharge can be!

AND, you have the niggle, that with fresh charge coming on one hole in teh cylinder, and exhaust gas going out of another; there is little to stop fresh charge depoarting out the exhaust port with teh brined charge, or burned charge lingering and contaminating teh charge.

It really IS astounding that a two-stroke can actually work at all, if you think about it; BUT; 1920's/30's boffins tried exploiting the pottential a two-stroke offers of firing ever revolution, and hence offering potentially twice the power for the same weight and capacity.

The Spit single, was one innovation; two pistons and two cylinders NOT necesserily teh same size or even rising andf falling at the same time; but inlet ports in one cylinder, exhaust ports in the other. The Super-Charged two-stroke, was probably more viable and did more to adress problems though; doing away with crank-case induction, and simply using a mechanically driven pump, to squash charge into the cylinders.

BUT, we have Hitler to thank for the modern two-stroke!

Hitler set up a design studio; cant remeber its name; produced a lot of modern design icons. Chrome & leather office furnature being amongst them if I recall. HOWEVER; Hitler promiced the German people the Volts-Waggen... but they didn't get it! Too expensive for most, and prominant Nazi Parti officials were prioratised to the top of teh waiting list. The BMW 650 motorcycle, fitted with a side-car was the back-bone of trades transport, but they were almost as expensive to make as a Beetle. SO in apeasement; a design study was set up to concieve a 'cheap' easy to mass manufacture motorcycle.

The result was probably the first 'Designed For Manufacture' product ever made; and it WAS produced by Auto-Union, and sold under the brand-name of a sewing machine maker who had build bicycles, typre writers, and small motorcycles.... DKW - Das-Kline-Wunder..."The Little Wonder", as the RT125.

Nothing startlingly revolutionary about the technology of this machine, apart from THAT engine. It was a two-stroke, but DISTILLED down to the bare essence of 'engine'. THREE moving parts! A piston, a con-rod and a crank-shaft.

And it was easy to make; the difficult timing and assembly of a four stroke engine, setting the phasing of the cam-shaft and piston so that the valves opened at teh right time; all taken care of by the holes in teh side of the cylinder. If you do up a nut and bolt; you could build a DKW engine, it didn't need skilled knowledgeable technicians.

Bike was built under-licence or roundly copied without accross europe, before WWII. And after, the licence was offered widely; the bike being built in Britain for many years as the BSA Bantam.

The 'original' DKW factory, contunied making the bike, in divided East-Germany, as the MZ RT125, and was developed by ex Auto-Union Technician, Water Kaaden, to who can be considered the 'Father' of the modern Hi-Po two-stroke; pioneering tuning techniques, that included the disc-valve and teh 'harmonically tuned' expansion chamber exhaust.

Another Licence was granted to Harley Davidson, and that found its way to Yamaha curtecy of the US reconstruction of Japan; and resulted in the Yamaha YA1, and thier innovation of the 'reed-valve'.

Kaaden's Disc-Valve, and Yamaha's reed-valve, drastically improved the trapping efficiency of the two-stroke engine; now when the piston rose, it would suck in an almost full cylinder displacement of charge, and the valve would hold it there as the piston fell.

Kaaden's pioneering 'Expansion Chamber Exhaust' combined with a novel opposed-port 'fountain scavaging', seriousely improved the efficiency above the piston, the fountain porting more effectively washing exhaust gas out ofthe port, without contamination; the expansion chamber exhaust, creating a shock wave stopping the fresh charge dissapearing down the exhaust!

These developments; made the two-stroke engine enormousely more efficient, without hugely increasing the simplicity. Reed or disc valve added just one extra moving part; the exhaust was just a different shape!

The BSA Bantam, 125, with air-cooled, piton ported engine, made maybe 7bhp. The addition of a disc or reed-valve, and an expansion chamber saw power leap to around 10bhp or more. Evolution of this confection, saw power grow, rapidly, and the 'last' air-cooled 125 GP bikes were pushing around 30bhp.

Most of that evolution, coming in barely a decade, the 1970's.

By that point; increasing the number of ports, making the wider, making teh port timing more radical, REALLY brought the two-stroke to the point where to get any 'more' from it, demanded more complexity, and started departing from the fundemental 'engineering elegance' of the design.

'Auto-Lube', a mechanical pump to meter two-stroke oil into the crank-case, was an early departurte; that made its way to production bikes, as it made them more user freindly. But, probably doubled the number of moving parts in the engine! Did stretch the capability of those wide clerance roller bearings though.

Liquid Cooling; feature of the pioneering Scott; but with 'fire in the hole' every revolution, two-strokes needed the extra cooling to handle the sort of power they were producing.

Then, with more and more radical porting, and more extyreme expansion chambers starting to create 'the power-band', the 'Power-Valve' to change the harmonic tuning 'on teh move' was required.

THAT takes us to the 1984 Yamaha RD350YPVS, and it was only JUST less complicated than a four stroke.

Phenominon of the two-stroke, is that due to these idiocyncracies of 'tuning' relying on shock waves and harmonics; the efficiency reduces with cylinder capacity. There is an 'optimum' cylinder capacity around about 150cc, becouse Cylinder wall area to put ports into starts decreasing with larger capacities. Much over 250cc and the reduced cylinder wall/port area means that they struggle to flow as much 'charge' or make more power. So, to get more power, rather than making a larger capacity two-stroke, you have to make a multi-cyclinder one.... and again, its adding complexity and weigh.

AND The 500-fours, really demonstrated the deminsihing returns of advancement in the two stroke concept. As teh spec comparison shows, by 1985, the advances in two stroke technology, really had erroded the dadvantages to the point that there was little practical advantage, and very little more to be gained.

The practical engineering limits of that 'dry' crank-case and open journal bearings, pretty much marked the threshold. The reliability of the two stroke, up until that era was still reletively acceptable; motorcycles, in general, tolerated much shorter service intervals, sacrificing reliability for performance, in a consumer enviroment that was accustomed to high maintenence.

But, the Honda CB750 of 1969, launched at around the time the two-strokes really started to 'hot-up' was showing how motorcycles COULD be built to a new, much more 'consumer freindly' standard, demanding much less skilled attension. By the mid 80's, with the new breed of water cooled four-stroke 'fours' with sophisticated overhead camshafts and four valves per cylinder; the technology was 'beyond' the DIY freindliness of the old push-rod twins of yore; and modern manufacturing techniques, closer tolerences and pressure fed hydraulic plain bearings offered a new level of 'sealed for life' durability, ready to be exploited that the two-strokes simply couldn't utilise, or at least not without even MORE added compelxity or another quantum leap in technology.

Meanwhile, outside influences were working against the two stroke; the main atraction of a two stroke is its reletively high power to capacity ratio. But really, the only place that is of any real merit is where artificial csapacity restrictions are imposed.

The licencing laws in many countries impose arbitery capacity limits; we have a 125cc capacity limit on a provisional / A1 licence. That A1 125 licence made hi-po 125's very popular in Italy for many years; a 250 capacity restriction in Japan, made the hi-po 1/4 litre bikes viable; and it was merely the arbitery 500cc capacity limit on GP racing regs that made that the capacity of those engines.

Competition regs dating back to the 1950's banned supercharging; that could have lead two-strokes down a different avenue, and potentially overcome the dry-crank/loose bearing, and some of the emmissions problems. But would also have aided the four-strokes that might have utilised turbo-technology.

The 1960's, saw the number of gears limited to 6 ratio's, in an attempt to kurb the ludicorusely highly tuned two-strokes with razor powerbands. That restriction has deturred development of more spohisticated and high power 'variable-ratio' (scooter) transmissions, that may have favoured raucousely tuned two-strokes.

The late 60's/early 70's saw the cylinder restrictions, 125-single, 250-twin, 500-four, that actually benefitted the two-strokes, imposed to kurb the MV and later Honda's 'Screaming-Sixes', that were horendousely expensive, factory specials.

Meanwhile, on the road, on a full unrestricted licence; bikes are bikes, and doesn't really matter what capacity the engine is; it's how much power it's punting out, and how fast it goes, and how well it goes round corners.

Why, make life difficult, trying to meet racing regulations, building a small displacement, hi-performance two-stroke, when you can get the same power simply building a slightly bigger four-stroke?

And these days, that, "Little bit bigger' is the 130bhp of the Yamaha R6, that betters many of the open class bikes of the RD500's day!

The two-stroke's 'Day' was over by the mid eighties and the RD & RG. The technology 'push' of what could be done, had reached the buffers, while the 'pull' of what technology people wanted, was waiting for a four-stroke express; and like the hey-day of steam, while we may mourn the beuty and the passing of the era; it was dirty, and outdated and at the end of the road.

I am sooooo not worthy.
I don't know what to say, other than I'll take your experienced word for it.
So there you have it folks, 4 strokes are better and make way more sense on all departments.
Saying that, I bet most of us will just keep on loving 2 strokes anyway.

The RD500 remains a land-mark motorcycle; the pinicle of two-stroke tech, and the buffers at the end of that technological avenue.

For my personal two-stroke homage? Well, that lives on in my Montesa Cota and air-cooled Yamaha DT. Two-strokes from the zeneth years; maximum effect from minimum technology. A single, air-cooled cylinder, and no surperflouse equipment or systems, to detract from the ethos of high-power, light weight simplicity.

A different take on teh same nostalgia; and ultimately that is pretty much all the two-stroke reverence is. Like folk preserving steam loco's. Yes, the Mallard was faster than a modern pendelino, and far more evocative, with sounds and smells and everything else; BUT for the most part, the old steamers weren't those headline machines; they were smelly, smokey, cantankerouse, high maintenence dinasaurs, that cost too much to make, too much to maintain, and too much to run, and a Diesel electric, maybe boring, is just SO much more useful, if less 'interesting'.[/quote]

[Dilyan]

Just in case someone missed that:

[ScotsLass]

Sorry, I have no idea why my reply there ended up in the middle of your post.........it must be a blonde thing

[Nexus Icon]

This thread shows that quote-retards come in all shapes and sizes.


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Greetings from Shitsville!

[Dragonfly]

[sickpup]

[ScotsLass]

This is not as bad as I have seen it, least you have knowledge of bikes and a lot of members are talking to you civilly. Some are just arseholes who bring the place down. People like that are everywhere. Used to be so much more arseholes in here. There are more decent ones here than immature boys. If you stick about you are worthy , most woman run. They cant get rid of me [/quote]

Thanks
I'm starting to get settled in now, so I won't be doing any running away. Besides, I've just read another post here that is worse than mines for setting myself up for all the grief. A cyclist has come on here complaining about bikers not giving them enough space on the road
Now that has to beat me hands down on the stupidity stakes, lol
Also, I really don't know much about bikes to be totally honest, except for how I feel riding a bike, which is awesome. Hopefully that is enough reason for me being here.........and the promiss that I will try harder.

[Noxious89123]

[ScotsLass]

[Rogerborg]

[Dragonfly]

[Polarbear]

[ScotsLass]

[ScotsLass]

[sickpup]