[3833]

Well..

The Hiyabusa engine is making 175 at the crank (>155 at the rear wheel) from a 1.3L engine, includes both engine AND transmission, so why bother with the overweight, lower tech approach, which requires designing a new engine, and who's 200 lbs does NOT include a transmission?

 

[seruzawa]

Omigosh! 1 HP per cubic inch! (sarcasm off)



Don't forget that you have to add your radiator/cooling system as well as a transmission which will make the entire package make a GoldWong look small.

 

[23063]

Why bother with a pushrod engine anymore these days - sorry HD, I still love ya. You can get twice the horsepower by just reving the engine twice as fast. There are plenty of oversquare engines, with cams on top to produce all the power you want. What's needed is light weight. We went backwards in the '70s through the '90s with overweight bikes. Now we're getting light weight and high horsepower. Riding bikes is mostly about going around corners. You can go fast in many types of vehicles, but only bikes go fast around corners. For that you need good brakes, suspension and chassis - you don't need much motor for that.

 

[Mashuri]

Well, actually it's the opposite. Sports cars, with their 4 wide contact patches and low CG's, corner better than bikes while the bikes tend to out-accelerate them on the straights. But I get the drift of where you're coming from. Keep those bikes revving higher while getting smaller and lighter!

 

[Benji155]

Take the SV650 for instance (I can hear the sarcastic responses coming already). Power-wise it's nothing spectacular, but it only weighs 426lbs. ('99 model) fueled up. That's the same weight as an R6 ('99 model), but with a whole lot more torque available down low. In the tight stuff it'll keep up with or go past just about anything else.



What I can't understand is how Motorcyclist can give the 600RR the crown when it gained weight. It's roughly the same weight as last year's GSX-R1000! Unfortunately, the new Gixxer thou' has gained about seven pounds this year. Also unfortunate, both new SV 650s have gained some pounds as well. I thought the special mold-casting thingy was supposed to lower the lard. If I have to ride something with that new ugly frame it ough to at least be good for something other than stiffness. The old bike was plenty stiff to me. It seems like manufacturers are backtracking a bit, hopefully this trend goes back the other way. Hats off to Kawasaki and Yamaha though for lowering the weight of their 600 even more.

 

[seruzawa]

Yeah! And what about the VFR and Concours too!

 

[mike_root]

Hey! Listen!! Forget that motor...I have some plans for this wonderful flying concrete boat that would make marvelous motorcycle!

 

[KPaulCook]

I think a company in Australia built a V-8 sport bike called a Drysdale? Maybe I am wrong or lying (right longshyt)? I don't think it was pushrod though.

 

[KPaulCook]

Look the New Drysdale 1000-V8 Cruiser:

click here for link

 

[SmokeU]

Evidentally you need to catch up on your reading. A couple of years ago or so, Motorcyclist(I think) did a head to head comparo of a Corvette Z06 vs GSXR 1000 on a drag strip and a road course(Streets of Willow or something). The GSXR stomped the Z06 in every test, and on the road course actually cornered at higher G loads than the car. They were noticably higher too.

 

[SmokeU]

Re: Look the New Drysdale 1000-V8 Cruiser:

Looks like a Monster rip off. Bad pics, can't see the V8....if there is one

 

[13630]

Why bother with a pushrod engine? BBecause they are easier to modify to get big power. Just look at the NHRA and NASCAR- they do just fine with pushrod engines. And there is a large group of people out there riding motorcycles who really don't care about going fast around corners, because you can't on the street.

 

[KPaulCook]

Re: Look the New Drysdale 1000-V8 Cruiser:

Try this one

http://www.motobykz.co.uk/Drysdale/Drysdale_WSB_2004.htm

 

[ShadowPhil]

scaling down each dimention of a 3-dimensional object will reduce the overall size of the thing by a factor of 8. So the weight should go down by a factor of 8 (which is good), but the cubic inches will also go down by the same factor. So you would have a 50 pound engine with 50 cubic inches producing 25 horsepower.



If you wanted to make the package 200 pounds, instead of halving each side, you would need devide the dimension by the cube root of 3. Each side would be a bit under 24 inches - then the rest of the numbers should be correct. 2 cubic feet is a bit large to stick in a cycle.

 

[nokneedragin]

He was taking 2 yamaha 400 i4's and slapping them together. Funky idea, don't know if he was getting the HP, or torque number talked of here.

 

[TL1000SV]

Um, a little math error here. If you reduce all of the dimensions by half, you will cut the bore by half as well. Displacement is a product of the square of the radius of the bore, so your displacement would be on fourth of the original engine, giving 50 Cubic Inches (about 830 ccs). But it would be lighter than you stated by about a fourth as well, and power would likely be higher than 1/4th of the original 220, due to lighter reciprocating mass and a higher redline.



Sounds a lot like the V-8 a guy built out of two FZR 400 engines a couple of years back...

 

[3833]

Sorry, wrong answer...

Compare the dyno chart for the GSXR-1K

http://www.motorcycle.com/mo/mccompare/mcphotos/02opendyno.motml

with a Harley Deuce

http://www.motorcycle.com/mo/mccompare/cruisers/mcphotos/01deucephoenixdyno.html

The GSXR, although being "only" 1L rather than 1.5L, is making almost the same power at low RPM, while being stratospherically more at high RPM.

The only reason you don't really see engines like that in cruisers is because 95% of the cruisers are V-twin engines, chosen for looks not performance.

 

[SmokeU]

Re: Why Pushrods? I'll tell you why

I take it you don't know that Ford truck engines are OHC??

 

[seruzawa]

Re: Why Pushrods? I'll tell you why

True, but GM's new truck engines are pushrod and perform at least as well as Ford's.

When engine RPMs are limited there is no real advantage to OHC. OHC engines in bikes like the Shadows or V-Stars are an unneceassry complexity. In a truck engine where you want low end power OHC is pointless. Ford is probably using OHC more as an advertising ploy than for any real engineering requirement. The engines don't get anywhere near the revs to suffer from valve float. Neither do the engines in most Japanese cruisers. Even Yamaha went back to pushrods to lower the center of gravity in the RoadStar engines.

 

[13630]

Re: Why Pushrods? I'll tell you why

And also, like I said above, you can get just as much power out of pushrod engines as you can OHC engines. Just look at NHRA.