I am amazed at the power and speed that I see in the twin and four cylinder streetbikes on speedvision! Someone fill me in on how these bikes are producing so much power and speed. Are they using every trick in the book or what? What would it take to come close to this performance in a 650cc 4-stroke single QUAD? Is the twin cylinder the key or is it something else? I think the motor technology in the DS650 is based on 60's technology! What can I do to it to make the power state-of-the-art?

 

GP race bike: price tag ~$250,000.00

 

OK, that must be overhead or something, not just the parts? Even just an off the shelf 750 twin doubles the HP of the DS650, how come?

 

The GP bikes that you are most likely seeing on Speedvision. Price tag: ~$250,000.00

...Titanium, carbon fiber, engine technology the likes most commoners wouldn't even dream of...

Most of the bikes live at 13,000+ RPM.


Try looking at these...some spec's that are PUBLISHED(so probably close but not the REAL deal).

http://www.europark.com/ny-machn/ny-nsr500_1996.htm

http://www.europark.com/ny-machn/ny-apr400_1996.htm

You'll notice that most of them are two stroke 4 cylinder V formation engines. Potent.

For a four stroke, you can get modest horsepower figures(for equal CC's), but then you're working against weight and friction(valve train=HP loss).

To get those kind of HP figures, it really becomes a function of RPM. An engine is a air pump, the more air you can get to move thru it, the more power it will make. Add extra cylinders there is less "free-wheeling" so to speak, that the crank is being driven thru the entire revolution by each cylinder firing(typically about 120 deg. apart). If you can get the fuel and air in to be ignited, and just as importantly, to exit the cylinder you create more power.

Look at what we do to engines to get more power...larger head pipes--flow more out, bigger carbs--flow more in, larger profile cams--allow more mix to be drawn in and again expelled within certain degrees of crank revolution, higher compression ratios--more "bang" when lit off, hotter ignitions that are able to ignite the mix under high compression ratios...................

You can get those kind of horsepower figures out of your motor, but it has to be designed to survive under those conditions (high RPM, high load), and also function well too.

It's purpose built engineering, you can't expect a Yam. Grizzly, while it is 600 or so CC's to be able to create the same power that a 600cc CBR-F3 would be able to, it's purpose built(while not even addressing the weight issue.). Fortunately there are some motors that tend to be over-built from the factory which thankfully gives us the ability to stretch them further and create more HP/Torque.

Power often becomes a function of RPM and getting everything else in sync with it to be able to sustain, function within, and SURVIVE those parameters.................................

This is why all of us stand around and spend hours staring at our engine components, just hoping that we can find that one more little secret key that will allow us to unlock our engines power potential even further..................

 

I would have to agree. When it comes to any racing engine, almost everything is fabricated (titanium, chromolly, tungsten rods, pistons, etc.)

It's like saying "Nascar uses a Chevy 350 and get 750 HP out of it without nitrous, supercharger, or turbo, how?"

The lighter the rotating assembly (crank, rods, and piston) the higher rpm's you'll turn. The higher rpm's you'll turn, the larger the HP curve.

Also, with a street bike engine (650cc = 4 cylinders) this help with vibration rather than one 650cc piston trying to churn out 16,000 rpm's.

This smoothes out all that violent HP.

 

Street bike motors like what I have in my Ninja are highly tuned. I talked to one guy that said it would only cost a couple of hundred bucks to blue print my motor because it is so highly tuned. Most race bikes like what you saw racing are designed for high rpm HP. Any below 6000 rpm and these bikes stumble and studder. Street bikes are actually the test bed for the race bikes. They come out with something new and see how well it works on street bikes. If it works great they slap it on a race bike. Quads are designed to survive punishment for years. I have ridden my banshee for over 2 years now and still have the same plugs in it from when I bought it. My Ninja has had 4 tune ups, and about 5 sets of tires. You always get what you pay for.