Motorcycle owners: I have a question about V-twin power output.

[nitrox28]

Ok. I just sold my ZX-7RR and I am looking at either a Harley Davidson 1200 Sportster or a Suzuki 1400 Intruder. I've never owned a cruiser or V-twin before and I'm confused about the HP and TQ numbers. The Intruder only has 63hp and 105ft/tq. That's a really low horsepower number, but the torque is huge. The Sportster is the same way. My Ninja was a 750 and it had around 120hp but only had around 90-95ft/tq. What gives? I would think a large V-twin would have ALOT more horsepower. Could someone explain this?

[Slick26]

Its normal for V-Twins to push more tq than hp. I'd say, most bikes that are v-twins that is the case. There are a few out there where the hp and tq numbers are closer together, but generally there's more tq than hp. I dont remember why that is though. Possibly because there's only 2 pistons doing all the work? I have several friends that just bought v-twin bikes, one of them is a member here, and they swear by having more torque than hp now after switching from a sport bike. A bike to consider, that has gobs of both, is the new Suzuki Boulevard M109R... what a crazy ass monster of a cruiser. And also, I think that one has slightly more hp than tq. I think its 127hp and 119tq, could be wrong though. Either way, its a sick looking bike and rides even better. Kicked the crap out of my YZF and thats half the weight/size. I'm thinking of upsizing now too...

[nitrox28]

Thanks for the input. I looked at those bikes, but they are WAAAY out of my price range. They are huge allright!

[Slick26]

Yeah they're big. But suprisingly balanced. What's your range then? New (as in meaning not used yet) 2005 Yamaha Warriors are going for like $10k. They sell for $12,999 new. I personally wouldnt recommend a Harley, but I wont knock on them either. I just know a bunch of people that have had some bad luck with them. Not as good quality as they put on. Especially for the money. But thats just my .02.

[joestacey06]

Get the Intruder. Very nice bike. My buddy has a 1400 and has had only 1 problem. The relay for the starter went bad. $30 later he was on the road again. Other than that it's a sweet bike.

[V8KILLR]

Ok, here’s the physics why Vs engine configurations power and torque outputs respond differently then I4s. Torque in physics is the same as work done on a system. As a simple example, say you are at the gym and you pick up a 25 lbs dumbbell and raise that weight 5.5 feet. You have done 5.5 ft X 25 lbs = 137.5 Ft.*lbs of work on the system. Notice that then is no time evolved in this example…it does not matter in regards to work / torque if you took 5 seconds or 1000 seconds to lift that dumbbell. So this is where horsepower comes in. Power is the amount of work / torque preformed in a given amount of time.

So now that you have the physics ABS down, I’ll move on to engines. Let’s say that you’re looking at two different engines, a Kawasaki ZX-12R and a Buell Firebolt XB12R. Note that both have the same displacement, 1200 CC. Let’s just say to make things easy that every thing is equal except for engine geometry. The ZX is an I4 that from the numbers I’ve looked up puts out 159.8 HP and 91.4 Ft.*lbs and the Buell is a V engine putting out 103 HP 84.0 ft.*lbs. So clearly in comparing the two bikes, the V in comparison to HP, produces more torque. To know why this is the case, we have to look at the bore and stroke of these engines, which is as follows below:

Buell - 88.9 mm x 96.8248 mm
Kawasaki - 83.0 x 55.4mm

So let’s say that the force (lbs are a force) on each piston is only based on geometry. That is to say that the area of the piston is all that matters in this example when it comes to force. So let’s look at bore for this. Total area = (pi x bore squared / 4) x # of pistons:

Buell – total area = (3.14 x 88.9^2 / 4) x 2 = 12408 mm squared
Kawasaki - total area = (3.14 x 83.0^2 / 4) x 4 = 21613 mm squared

Ok, so although mm squared is not a force, let’s just call it a force since above I stated that we are looking at engine geometry only. So to get a torque / work comparison, we need the travel distance, like the amount moved in the above dumbbell example. This is only the stroke.

Buell – total torque based on geometry = 12408 mm squared x 96.8248 mm = 1517111
Kawasaki – total torque based on geometry = 21613 mm squared x 55.4 mm = 1198383

So basically per engine rotation all things equal except for engine geometry, the V produces more torque then the I4. This is your key take away, if I’ve lost you.

Ok, so why more HP on the I4 you may be asking. This is due to the high RPMs. Since the I4 has smaller components, a.k.a. rotational mass (smaller pistons, small connecting rods and so on), then the V, it can reach much higher revs. As way above stated, HP takes in account time. Well, that’s just what RPMs are…rotations per 60 SECOND. Therefore, since the I4 can rev harder, it can get more HP.

Not sure how I did exsplaning this. I’d be happy to get you or any one else my cell, because a phone would be a MUCH better way to say this.

Jason

[snaggeltooth]

Yeah they're big. But suprisingly balanced. What's your range then? New (as in meaning not used yet) 2005 Yamaha Warriors are going for like $10k. They sell for $12,999 new. I personally wouldnt recommend a Harley, but I wont knock on them either. I just know a bunch of people that have had some bad luck with them. Not as good quality as they put on. Especially for the money. But thats just my .02.

Yamaha's make great big cc bikes..You might want to try the Valkyrie by Honda also, it has the same engine as a Gold Wing....

[D!ck]

ever been in a car wreck? if u have, then imagine if u were on a bike when it happened. there are no fender benders on bikes. i bout got ran over by a lil old lady in a quad cab dodge. shes real sorry, but ur fucken dead, and not excepting apologies at this time.

[D!ck]

everybody says they are such good drivers. i dont disagree with that. but u cant control other people.

[snaggeltooth]

ever been in a car wreck? if u have, then imagine if u were on a bike when it happened. there are no fender benders on bikes. i bout got ran over by a lil old lady in a quad cab dodge. shes real sorry, but ur fucken dead, and not excepting apologies at this time.

Have you ever road a bike ???

[oneBADDz]

ever been in a car wreck? if u have, then imagine if u were on a bike when it happened. there are no fender benders on bikes. i bout got ran over by a lil old lady in a quad cab dodge. shes real sorry, but ur fucken dead, and not excepting apologies at this time.

Why do you do this in every thread about bikes? every time? We get it, we got it from our mommas and everyone else. Thanks for caring about us all, now we got it though

[pecha]

check this one out: http://www.starmotorcycles.com/star/...05/0/home.aspx

just change the muffler
I love vtwins - nice torque from the bottom - just like american muscle

[310stanger]

seriously. everytime i read a bike thread someone is telling you how dangerous a bike can be. duh. we know. but you know how many motorcyclists there are out there that havent been in an accident in years of riding? your chances of getting in one are no different then a car. they are jus potentially a lot more dangerous. but nobody wants an accident. you go out in your car every day for years and nothing happens. you dont ride a bike nearly as much as you drive your car. theres tons of rider safety courses i think are of great value. the danger i think motorcyling gets is the fact that everybody that wants a bike these days thinks they need so much more bike then they do. the threads that piss me off are from the guys that havent ever ridden a dirtbike and they want the fastest 600 on the market. dude, practice on a 250 first, take some courses and move up. they are so concerned with running 10s on a bike nevermind how to ride it. most people dont realize how much faster you feel your going on a bike. my motocross bikes top out at around maybe 70. but the acceleration would make u think ur going way faster. now a 600 sportbike? it will completely rape my motocross bikes. keep in mind 600s are on the low end of sportbikes. a top level 600 has around 105 to 110 horses whereas the 1000s are putting out 170. these are in my opinion the closest vehicles available to the public that are basically race machines. jus my 2 cents. as far as the vtwin thing. the physics of mass are primarily what prevents similar horsepower figures to an inline 4. the big vtwins vibrates so much more due to reciprocating mass. 2 big pistons are way bigger then 4 given an equal displacement. because of this they are not able to rev as high as the 4 cyl. one of the easier ways to achieve hp is throuhg higher revs. now as far as torque goes, one of the benefits of a twin is the fact that they have very long strokes. the stroke on the average i4 is not very long at all. you enounter a lot of packaging problems in a motorcycle frame. so manufacturers try to make the engines have power curves most useful for the application. exceptions to these hp rules as far as twins go would be a bike like the honda rc51. if you want a twin and a lot of power, that might be a bike to consider. this bike would be very similar to the feel of the zx7rr jus not as much of a screamer.

[310stanger]

oh yeah, the yamaha warrior kicks ass. whenever looking at buying a motorcycle always consider a yamaha. the fit and finish, dependability, performance, looks, ergos, value and resale value can not be beat. i sware by them. they also have a model line that covers nearly any need you could have.

[D!ck]

Have you ever road a bike ???

u can read cant u ???

ever been in a car wreck? if u have, then imagine if u were on a bike when it happened. there are no fender benders on bikes. i bout got ran over by a lil old lady in a quad cab dodge. shes real sorry, but ur fucken dead, and not excepting apologies at this time.

i ditched it and got lil fucked up.

[D!ck]

everybody says they are such good drivers. i dont disagree with that. but u cant control other people.

[snaggeltooth]

u can read cant u ???


i ditched it and got lil fucked up.

you did notsay you were on a bike... I thought someone was just doing the rest of us a favor ...

[D!ck]

you did notsay you were on a bike... I thought someone was just doing the rest of us a favor ...

wow. old people i thought were cool. like sarge. but oll snaggle just needs a new ride so at least he could impress somebody. my chopper>your ta

[pecha]

you gotta ride like you're invisible
always expect that people around you want to kill you
you do that - you'll be fine

[snaggeltooth]

My , arent we the sensative one. I see how you always have a cute little coment to throw in these threads.. Maybe that is the only way you can impress people ...