A little history

[riffraff]

Excerpts from a couple Yamaha history sites

More than any other manufacturer, it is Yamaha that forces out four-strokes engines from Grand Prix racing.
 
And from another site

By 1970 the number of models had expanded to 20 ranging from 50cc to 350cc, with production up to 574,000 machines, 60% of which were for export. That year Yamaha broke their two-stroke tradition by launching their first four-stroke motorcycle, the 650cc XSI vertical twin modeled on the famous Triumph twins.

   Yamaha realized the long-term potential of the two-stroke engine and continued to develop two-stroke bikes, concentrating on engines 400cc and under.

The underlines are mine, there was more but this was the most interesting 

[opfermanmotors]

I have a little history series on youtube.

Legends of Dirt Bike History (HD)

Legends of Dirt Bike History Part 4 (HD)

Legends of Dirt Bike History Part 7

Legends of Dirt Bike History Part 8

[SachsGS]

The XS650s were copies of Horex OHC parallel twins, not Triumphs.

[JETZcorp]

The Yamaha history kind-of explains why they haven't dropped the YZ's.  They've been doing two-strokes for so long, it would be the end of a tradition that's been around since day one.  Kind of like how Porsche can't bring themselves to make a car that doesn't have styling cues from the original 356 from way back in the day, and how they still put the engine in the "wrong place" in tradition.  In both cases, the traditional values lead to a uniquely awesome product.

[SachsGS]

I think the top brass at Yamaha are not stupid and "want to keep that two stroke door open".

"Wrong position?". How can a "kazillion" Volkswagen Beetles be wrong?.A long time ago I was at a ski hill with a girl friend and her brother in law was trying to climb this snow covered hill with a "hopped up" Chevy Blazer. He was making it about 1/3 of the way up and he was teasing her that her Beetle couldn't even make it over the hump at the start of the climb. Well, enough was enough, and so I jumped in the old Bug and drove it right to the top of the hill!

[riffraff]

"Wrong position?". How can a "kazillion" Volkswagen Beetles be wrong?.A long time ago I was at a ski hill with a girl friend and her brother in law was trying to climb this snow covered hill with a "hopped up" Chevy Blazer. He was making it about 1/3 of the way up and he was teasing her that her Beetle couldn't even make it over the hump at the start of the climb. Well, enough was enough, and so I jumped in the old Bug and drove it right to the top of the hill!

x2 on that, how can it be wrong to have all the engine weight over your drive wheels?

[factoryX]

Well put it this way, one nick name for the Porsche 911 turbo was "The Coffin". With all the weight in the back it makes it extremely tail happy and very hard to drive. These things are famous for spinning out and off the road into a tree lol. The reason its still being made is that its what the public wants. And as for the question of whats wrong with all the weight on the rear wheels, if it is not a drag car, their is no reason for it to be there. And the beetle was a horrible car. Only thing cool about it was it's own class in the baja 1000, and the movie lovebug, which Lindsey Lohan and Disney ended up killing.

[SachsGS]

Given the racing successes of the 911 and it's derivatives I think Doktor Porsche knew what he was doing.

As for the Volkswagen Beetle, it and the Austin Mini came to define the modern compact car. The Beetle is a stunning example of industrial design and how it can change the world.The fact that Volkswagen is the world's largest auto manufacturer is due in no small part to the Beetle.

[opfermanmotors]

I think they need to make a car with the engine in the passenger seat.  That way you can show everyone "look at MA INGINE!" without having to pop the hood.

[factoryX]

All it has performance wise right now is 0-60 in like 3 seconds, other than that a  corvette zr-1 will destroy it everywhere else.  And imagine that a corvette has equal weight distribution. And as for its successes, why would they change a 60 year old design? They tried to update it with the 928 and people wanted the 911 back.
porsche 928
Opferman the video's are awesome by the way.

[SachsGS]

The 911 has a lot more then quick 0-60 times. It is the most recognizable sports car in the world. How fast would that Porsche be if it had a displacement equal to the zr-1? For those who demand more mainstream handling characteristics might I suggest the Boxter and Caymen models.

[factoryX]

buddy its not all about power, rofl. There is a lot more involved with a car than simply throwing horse power at it. All the Porsche is, is a status symbol. All I am saying, is that rear engine cars are not very practical, and the 911 proves my point. The 911t/911 is out dated and was supposed to be replaced! This is from the words of Porsche!  And as of right now, Porsche sales at the moment are dead because nobody can afford a car that constantly breaks down, rofl.

Also, this is as close to a corvette motor in a Porsche your ever going to get to get, the ls2 motor only weighs 400lbs pushing 500hp+:
Porsche 944 LS2 V8

[SachsGS]

I've driven both Porsches and Corvettes and I can assure you that I am no idle armchair critic. Shall we compare the racing successes of the 911 to that of the Corvette? Or shall we examine companies in question's bottom  lines. Let me see now, was it Porsche or GM that declared bankruptcy? Porsche 911s also have a reputation for being very long lived.

From the design vantage point of vehicle weight management/cost and powertrain packaging the rear engine concept is one of the most efficient. That is why Porsche selected the design 80 years ago and is also why companies like Volkswagen and Tata are reintroducing rear engined cars now.

I've built many a small block Chevy, a design that dates back to 1955. Trust me, the Porsche engines are a little more sophisticated.    

[factoryX]

 right now your going way over board with this whole sexual thing for Porsche. Its called weight balance my god. Would you ride a rear engine dirt bike? rofl. They are over sophisticated! Why do you think that the Chevy motor is considered an upgrade? You know what more sophisticated really means? more things to break and more weight.

[SachsGS]

My relationship with Porsches is strictly platonic, however, Alfas are a whole different matter...

Small block Chevys are plentiful and offer a lot of performance for little money invested.As well we must distinguish between weight management and weight distribution (balance).

Porsches are representitive of the German mindset of engineering machines to the "brink of the unknown" (some might say to the "brink of disaster").Corvettes are the product a different philosophy, that of offering a whole lot of value (performance) for not a great deal of money. I'm not really sure if you can compare the two, they come from two different vantage points and appeal to two different markets.

As for the rear engined bike thing, you've given me an idea for a "recumbant motorcycle".Thanks.

Now you'll have to excuse me, I've got a date with a red headed Spyder.