[Tigz]

From what you said above, Suzuki did it right with the M109R by putting a pair of cylinders bigger than the Hoss Boss and shorter stroke with a GSX-R motor design. Making it generate more TQ in the lower RPM and generating HP at higher RPM. And installing a wider back wheel to put all that power to the ground. I can just imagine if it has another pair of Cylinders....hmmm. J/K...

I agree with the above...except that I wouldn't compare a Hoss Boss to a GSX-R...More like a GSX-R 1000and a Ducati 1098 or a V Rod and a Roadstar. At which one has a shorter stroke and longer stroke motor design.

 

[Paul-Panic]

I've always wondered about how well a performance V-4 engine design would function on a Motorcycle. I know the Honda Magnas have got them, but they're not exactly performance. Harley-Davidson might be able to compete with the Japanese companies performance-wise with a V-4 configuration.

 

[Tigz]

Honda VFRs are V4 along with the new VFR1200. HD will have to step out of their conventional motor design like they did with the VRod with the help from Porche to deliver that kind of performance in such a smaller displacement.

 

[Rambler]

so how does the kaw. 125 compare in this ? a 502 V8 is a big motor in the Boss Hoss.

 

[Tigz]

There won't be any comparison. It's like comparing a grape to a large watermelon.

 

[badmonkey]

Thank you for the informative response. I have a followup question to the original poster. I am hoping that someone here can provide a suitable response that might be able to help me, short of just simply trading in my Honda 2009 CBR 600 RR for a v-twin or the new Triumph Daytona 675 triple.

I am curious as to how I can best improve the lower range power of my CBR ? What kind of modifications can be implemented in order to achieve a decrease in the powerband for optimal within-the-city riding?

Thanks in advance!

Re: the 675. The 675 is a triple, which makes it like a 4 and like a twin at the same time.

The 675 has much more usable power (I wouldn't say it's on the "low end" since no 600 is going to have "low end" power) than the average I4 600. The powerband is much more linear. But, it also doesn't have that rush of power that comes on in a I4 (like when you're above 9k on your cbr, and it really starts to cook)--at the same time, it doesn't stop making power at 8k like a twin. IMO it's the best of both worlds--and would make for an awesome streetbike IF you can handle the ergonomics of riding one. If you like naked bikes and can't handle the body positioning of the daytona, triumph makes the street triple--which is an unfaired bike with a 675 motor tuned for more mid-range power and torque.

before you trade your bike in, ride a 675 and a twin. see if you like the power delivery on either better than you do on your cbr.

While we're at it, what's a good bike that makes lots of torque and HP throughout the entire powerband? Would make a pretty **** good streetbike.

**note** this dyno plot is for the 06 models of the bikes listed.

and while manufacturers and other people tend to focus on talking about a bike's peak hp#, a more practical approach is to compare the "Area under the curve" of the dyno plot.

I've always wondered about how well a performance V-4 engine design would function on a Motorcycle. I know the Honda Magnas have got them, but they're not exactly performance. Harley-Davidson might be able to compete with the Japanese companies performance-wise with a V-4 configuration.

The new Aprilia RSV-4 is a 60deg V4 displacing 998cc's. 185 bhp, 80 ft-lbs

Then there's the honda V-4 powered RC30 & RC45's. which are rare and worth hundreds of thousands of dollars (they were sold at dealerships, but only for race homologation purposes)

 

[Biker Dash]

While we're at it, what's a good bike that makes lots of torque and HP throughout the entire powerband? Would make a pretty **** good streetbike.

Well, if your looking for a bike with a torque curve that is as broad as the Pacific, and if it is going to be a bike that a beginner can feel comfortable on but even experienced riders can enjoy, I would recommend a Shadow 750. I can cruise along at 35mpr just fine in top gear, yet still accelerate smoothly from it. It does not produce a lot of power, but what torque it produces, it does so throughout 90% of it's rpm range.

If you want more, I hear good things about the 650 sized Ninja. And if your experienced enough for the big power producers, Most any liter sized bike will give you all the power you can handle on the street at reasonable rpm ranges. Some will give you way more than needed even.

More importantly, it is easier to shop around and find a bike your comfortable with, cause your very much likely to find one with plenty enough power down low for street riding. I could supply a list of good bikes for your purpose, but that would get long...

 

[Rambler]

i want power all the way through the RPM range.no more then 5200 and be able to cruise 120 all day

 

[Jay550]

With a built 1602cc Roadstar, the powerband is when you turn press the starter until turn off the key, or hit a tree, whichever comes first. I'll have dyno sheets in the spring, but it'll look something like this:

That might look a little strange to some of you non-star owners, so I'll explain it. The R* actually starts off with more power than a peterbilt, but it comes down a bit so you don't instantly destroy the clutch when you let it out, flip the bike over, or melt the rear tire. The average R* owner has owned 37 R*, typically in less than 3 weeks, because that's how long it takes to stop destroying them due to their complete awesome power. The drivers seat must have a back rest and 5 point harness, otherwise when cruising at 1mph-700mph, if you roll the throttle even a wee bit, the bike will accelerate so fast you'll fall off the back. To this date no one has owned a Roadstar and lived to tell about it.

So, I hope this has cleared up your question about power bands.

 

[builtdesign]

So just to re-cap and maybe simplify things a bit... Low-end refers to torque, and top-end refers to HP/RPM. Torque is the twisting motion from the (low-end) crankshaft. Torque times RPM equal HP.

So in laymans terms:

An engine with a long stroke will have a lot of low-end. Example: V-twin.

An engine with a higher RPM limiter will have more top-end. Example: in-line 4

 

[markk53]

I've always wondered about how well a performance V-4 engine design would function on a Motorcycle. I know the Honda Magnas have got them, but they're not exactly performance. Harley-Davidson might be able to compete with the Japanese companies performance-wise with a V-4 configuration.

Honda won the AMA Superbike titles for a number of years with the first and second gen V4 Interceptors, then both the world and AMA superbike titles with both the RC30 and RC45. So the V4 can do a good job when it comes down to it. Again, it's the state of tune. I don't know exactly what if any differences there are in cams, pistons, and heads, but it would be interesting to put the VFR parts from an 80s or 90s engine in the Magna if possible.

In a side note, it was interesting to us that Honda put the 180 degree crank, which produced better lower/mid range power in the Interceptor and put the 360 degree crank which puts out better hp in the upper range in the Magna. When all things are the same the 360 crank engine will outperform the 180 for HP. The really wierd part is that the 180 crank gives the Interceptor that distinctive V8 rumble like a mini-small block Chevy where the 360 crank gives the Magna a sort of flat drone which is a bit uninspiring. That should have been reversed for the sake of sales. Imagine a Magna with a set of pipes on it... sounding like a small block Chevy. A friend had a set of pipes on his 86 VFR and it sounded incredible - no mistaking it for anything else.

If I could have made one change in the mid 80s in the Honda line up, for sales sake, that would have been it. I guarantee you we could have sold the heck out of Magnas if they'd had that rumble. The cool thing too is that the 180 crank pipes for the Interceptor were 4-2s so there could have been a pipe on each side sort of for a balanced look. I could have pulled that bike out, fired it up, blipped it several times, then gone back in and written the sales order up for the starry eyed customer! :biggrin:

Sometimes it made us wonder who was doing the market research and making the decisions...

 

[markk53]

So just to re-cap and maybe simplify things a bit... Low-end refers to torque, and top-end refers to HP/RPM. Torque is the twisting motion from the (low-end) crankshaft. Torque times RPM equal HP.

So in laymans terms:

An engine with a long stroke will have a lot of low-end. Example: V-twin.

An engine with a higher RPM limiter will have more top-end. Example: in-line 4

Unless it's a short stroke big bore V twin like the Aprilias and the 4 is a longer stroke smaller bore like some of the older 80s models...

We had similar misconceptions when the Yamaha 4 stroke MX bikes came out. Guys were telling other guys that the 4 strokes were "easier to ride than a two stroke, so buy the big Yamaha", basing that "knowledge" on past experience with the old longer stroke milder tuned Honda XR series. Our first customer who came in with that line, bought the YZF425 on a Saturday and was sitting at the door of the shop Monday, after riding it about 50 feet with no wear on the front tire, but a fold marks on the rear fender... he traded it in on a 4 wheeler.

In other words, research the bike being considered for purchase before jumping in. You could find things aren't always what they seem to be. You can expect a lot of grunt from a Harley, but if you carry that thought over to an Aprilia or a KTM V-twin you might be in for a GIANT surprise.

 

[Biker Dash]

With a built 1602cc Roadstar, the powerband is when you turn press the starter until turn off the key, or hit a tree, whichever comes first. I'll have dyno sheets in the spring, but it'll look something like this:

That might look a little strange to some of you non-star owners, so I'll explain it. The R* actually starts off with more power than a peterbilt, but it comes down a bit so you don't instantly destroy the clutch when you let it out, flip the bike over, or melt the rear tire. The average R* owner has owned 37 R*, typically in less than 3 weeks, because that's how long it takes to stop destroying them due to their complete awesome power. The drivers seat must have a back rest and 5 point harness, otherwise when cruising at 1mph-700mph, if you roll the throttle even a wee bit, the bike will accelerate so fast you'll fall off the back. To this date no one has owned a Roadstar and lived to tell about it.

So, I hope this has cleared up your question about power bands.

:coffeescreen:

 

[67fire]

I don't know if this will help or hurt the info that has been shown/discused here
but, if you examine this dyno chart, you can basically see how this engine was designed
to have a very broad and usable power-band.
This engine, will pull like a tank from 3-9,000 with a very flat torque "curve".
So, just off of idle, it is very near it's torque peak.
The "sweet spot" is were the TQ. and HP peaks intersect. From that point , the HP takes over.
This engine was designed with very little camshaft lift and duration.
It would also be considered a "square" engine.
The bore and stroke are nearly identical. 72 mm bore X 66 mm stroke.
A square engine, makes a flat torque curve. It is an inline 4-cylinder.

Eric

 

[67fire]

Here is another example of a square engine. This time a V-8.
3.54" Bore X 3.5" stroke. This engine, suffered from an exhaust restriction
at 5,500. You can see where the HP and TQ just STOPPED!
This engine, was just coming alive at 5,000.
Again, notice the long flat torque "curve." Just off of idle.

Eric

 

[markk53]

67fire,

That first dyno chart does show a very good power spread, with a minimum of about 75% max torque available from 3000 rpm through the peak of 8000. That was what sold me on leaving my 550 drive line alone, the torque held at over 80% from about 3500 rpm through 10,000 rpm. The dyno chart that Cycle ran in it's 1990 test of the Zephyr 550 pretty much looked like that, but didn't sign off as quickly and wasn't quite as high of numbers probably due to displacement and the state of tune required to get that sort of power delivery. I figured if I messed with a pipe or cams it'd just screw up a good thing... if I wanted faster I should buy faster.

The problem for most riders is the psychological barrier of running the engine into the good power. Most riders seem to want to lug along about a thousand under the start of the power, thinking it's the best thing to do. The reality is an engine should be run in the range for which it was designed. I seldom drop below 3500 on either the KLX or the Zephyr and spend a whole lot of time over 4000 on the Zephyr.

I learned of the engine design reality when selling Hondas and dealing with the complaints about gas mileage and poor engine performance by the 1100/1200 Gold Wing riders who thought their bike engines were made by John Deere. They'd lug them around at 2000-2500 rpm and expect them to run smooth. Of course they didn't and we'd get the complaints. Honda told them and us the engine was designed for best performance when run above 3000 rpm and best mpg came in when kept between 3000-4000 rpm, downshifting if necessary. I can tell you from riding my 1100 Wing, back when, they were right.

In other words that bike in your dyno chart should not be run under 3500 rpm under any significant load. It should be worked in the range from 3500-6000 on a regular basis for optimum mpg and performance. Essentially that's the range it was designed to use. Very similar to my under square (58/52.4 bore/stroke) Kawasaki 550 in-line four.

Proving it still has a whole lot to do with more than just bore/stroke or cylinder layout. There seems to be a whole lot of relationship to cam lift/duration/timing and ignition timing/advance. On a Nighthawk S, a simple backing off of the 133 degree cam advance to around 105 will boost midrange noticably while losing around 3 hp... nothing in the bore and stroke changed.

For a more radical example, just consider how streetable the Vance-Hines pro-stock "Harley" engine is...

For a more common example, some engines have drastic reaction to removal of airboxes or changing exhausts. Usually those in a higher state of tune can have major issues due to flow dynamics and jetting. It's like sharpening a knife, when the edge is near razor sharp it's hard to get better, but when the edge is virtually blunt any sharpening is a help. The current supersports fit the former, some of the cruisers and dual sports fit the latter. Unstuffing my KLX boosted performance both in "seat of the pants" and side by side performance of it compared to another "control bike" (I'm not blowing money on dyno runs for a 40 hp single) and oddly enough in MPG, going from 50 mpg to 60 mpg.

It's not so simple as to involve an engine configuration of cylinders or of bore and stroke. Some time dealing with a variety of engines will demonstrate that. Also realizing how the power comes in helps too. If the power comes in higher, the rider just needs to stay in a lower gear. Any Ninja 250 rider can tell you about that. :thumbsup:

 

[scritch]

I just read a good article on torque vs hp:

http://www.vettenet.org/torquehp.html

 

[Tigz]

With a built 1602cc Roadstar, the powerband is when you turn press the starter until turn off the key, or hit a tree, whichever comes first. I'll have dyno sheets in the spring, but it'll look something like this:

That might look a little strange to some of you non-star owners, so I'll explain it. The R* actually starts off with more power than a peterbilt, but it comes down a bit so you don't instantly destroy the clutch when you let it out, flip the bike over, or melt the rear tire. The average R* owner has owned 37 R*, typically in less than 3 weeks, because that's how long it takes to stop destroying them due to their complete awesome power. The drivers seat must have a back rest and 5 point harness, otherwise when cruising at 1mph-700mph, if you roll the throttle even a wee bit, the bike will accelerate so fast you'll fall off the back. To this date no one has owned a Roadstar and lived to tell about it.

So, I hope this has cleared up your question about power bands.

I wouldn't brag about the Roadstar 1600 that much, compare to the power cruisers out like the Warrior, Raider, V-Rod muscle, M109R, and the Rocket. With these Muscle cruisers, it's a much smaller bike, lol.

 

[Biker Dash]

Tigz, it was meant as a humorous post lol

 

[GI Jack]

With a built 1602cc Roadstar, the powerband is when you turn press the starter until turn off the key, or hit a tree, whichever comes first. I'll have dyno sheets in the spring, but it'll look something like this:

That might look a little strange to some of you non-star owners, so I'll explain it. The R* actually starts off with more power than a peterbilt, but it comes down a bit so you don't instantly destroy the clutch when you let it out, flip the bike over, or melt the rear tire. The average R* owner has owned 37 R*, typically in less than 3 weeks, because that's how long it takes to stop destroying them due to their complete awesome power. The drivers seat must have a back rest and 5 point harness, otherwise when cruising at 1mph-700mph, if you roll the throttle even a wee bit, the bike will accelerate so fast you'll fall off the back. To this date no one has owned a Roadstar and lived to tell about it.

So, I hope this has cleared up your question about power bands.

oh god, thats the funniest thing I've seen all day.