[Rocket 6R]

I'm sure I’ll generate a lot of ill feelings on this post. Don't get me wrong, I love my SV1000S and didn't regret purchasing it.

Here's the story....

I managed to hit 165mph on my bike last weekend. I had a GPS with me and it registered in at 141mph. This is the fasted that I've had my bike up to and it was topped out. I think the only thing holding me back a little was the fact that I was not able to fully tuck in due to my tank bag. Even if I was I don't think I would hit more than 145mph, true speed.

Before I go any further I must say that I only hit top speed runs about once every two months. I do this in is a secluded road far away from the city limits and you can see for miles. I'll make these runs where there are no cars on the road, early Sunday mornings. I realize that there is an inherent risk doing this, but I try to be as safe as possible.

I have done a lot of mods to the bike and my last dyno run produced 117hp and 73torque. With this kind of power I would expect to see higher top speeds. The last run that I did was a 638 ft above sea level on a cool day. I weigh 235 pounds with gear on, however, I have shed about 20 pounds of bike weight after my mods. I have actually read an article in one of the sport bike magazines that say larger rides can sometimes reach higher speed than lighter rides when they tuck in as it helps remove the void between the rider and the wind screen, less of a wind vortex.

Since the last dyno run I have made some other mods to the bike. They include a BMC filter, lifted tank and snorkel removed. I do plan to have it remapped here in a couple of weeks.

I look at the current production of 600's out there and they are able to achieve high speeds than my bike, not to mention the 1000cc class bikes. So why is my top speed so low? Is it the lack of a RAM air induction or even full fairings? I do have a 16T on the front sprocket and when at top speed I'm about 1000rpm's away from my redline.

Any well thought out responses would be greatly appreciated.

Thanks, Rocket 6R

 

[oldbaldsob]

....I look at the current production of 600's out there and they are able to achieve high speeds than my bike, not to mention the 1000cc class bikes. So why is my top speed so low? Is it the lack of a RAM air induction or even full fairings? I do have a 16T on the front sprocket and when at top speed I'm about 1000rpm's away from my redline....

I'm no expert in this area but I think the SV's top speed is limited mostly by gearing and its engine design in order to offer a wide, fat spread of torque across the majority of the rev range vs the more peaky natured power delivery of 600 cc sportbikes. Do a 40-60 or a 60-80 roll on with no downshifting on the SV vs. any 600 cc sportbike and you will flat leave them behind.

Check out a recent post of mine here on an insurance thread: http://www.sv1000.zyns.com/forums/showpost.php?p=284575&postcount=4.
The SV1000 stomps the Ninja ZX-6R in 0-100 and in the quarter mile. The Ninja doesn't catch up to the SV until probably around 130 mph. I don't know about you, but I'd rather have a bike that kicks ass under 100 where you need it the most.:yes:

Just my $0.02. :msn-wink:

 

[2WIN]

Redline has a lot to do with top speed runs...

I guess to me 141 145 or what ever it is, is pretty awesome. I VERY seldom need to go that fast in town where most of my riding is done.

I went into buying this bike knowing full well it wasn't the fastest bike out there. Hence the low insurance rates. If I wanted to pay 800 a year to insure a bike, I would have bought a Busa.

 

[racerV]

I think it is just the nature of the beast. V-Twins seem to be geared more for low end torque and with that, you have a loss of top end power. They are also geared differently because of this. My solution to this issue was to buy a Busa Now I have the best of both worlds.

 

[ryanm8424]

the sprocket change. and the gearing. and the power band. its all a factor in the performance. our bikes are quick not fast. there's a trade off. also availabilty of torque and hp at low rpms. ie. not having to rev the bajeezus outta it

 

[Nukedog]

2 - 500cc turning almost 11000rpm is alot of slug to sling...

I4's have smaller and lighter reciprocating assemblies and can achieve 15000-18000 rpms and acheive their maximum power at those higher rpms hence more top speed...

The SV is a good torque bike that is NOT an SS - if you want a Vtwin that is "almost" and SS get an RC51...

 

[svtrev]

It must be your gearing as to why you top speed is low Had mine on the Dyno and got a genuine 130mph in 3rd speedo was only 2mph out I have hit 161mph on the road no 600s have come past me and in the midrange leave em for dust:banana:

 

[one2many]

Aerodynamics would be my guess...

 

[tjm73]

"Usable power". Take all your riding time and figure out how much time (percentage wise) you spend at speeds above 100 mph. It's most likely a realitivly small percentage. Every once and a while I see some kind of thread about this topic and I immediatly wonder what use a 180mph top speed is in the real world, on real streets with other traffic on them is.

You can't really use that top speed very much. And to get the ability to run that kind of speed, the trade off is almost always low rpm power. I would wager that 80-90% of your time is spent between 0 mph and 75-80 mph. Starting, stopping, accelerating and slowing down, cruising in traffic and the stop and go of the real world. Those top speeds are great for racing, and advertising, but, IMO, nearly worthless in the real world of street riding. 90% of the guys buy those 180 mph bikes for bragging rights, not because they have a real use for them or even the true skills to utilize the benefits the bike has to offer.

I just don't see the allure of being able to run a certain nuber for top speed because where I ride (when I have a bike, sucks being bikeless) I have laws that I kinda have to follow. My last bike had about 115 hp at the wheel. It was geared to have atop speed of about 140 at 12,500 rpm. It never saw it. But it walked away from bigger bikes like mad. It ripped where it mattered and wasn't concerned with what the max speed was.

 

[tjm73]

Aerodynamics would be my guess...

Along with where the power is made in the rpm range, what the rpm range is and how much power is made...plus total weight....

 

[Kyoseki]

You say you've done a lot of mods to the bike, would any of those involve changing the gearing of the final drive?

 

[Big Gig]

Sorry but ~140 mph is fine by me... but, slow?

SV is geared for Happiness, not madness.

I guess it is a generation thing and all. To me 140 is fine. But I am almost dead(38 yrs old):shock:

 

[D.T.]

Must be your weight, 235 lbs and the tank bag. I removed the stock tool bag, I swear it weighs 5 lbs. At the drag strip, I was in 4th gear, at around 10K rpm's doing 123 mph (according to their speedtrap?). Another guy said he was at 130 mph in 3rd? You could try 5th gear without the tankbag and see what kinda speed you get @ 10.5K. I still have yet to get a top speed run in yet, too chicken. I did get 155 indicated in a 1.5 mile stretch. I'd like to see what top speed in each gear is with a speedo healer. I'm thinking of buying one this spring.

 

[2WIN]

I'd like to see what top speed in each gear is with a speedo healer. I'm thinking of buying one this spring.

Do it!

Mine is spot on now! I was running hot one day with another guy on an SV and he couldn't believe he was doing almost 120mph... NooB...

I said yeah but we were doing 110... Speedo-Healers rock. GPS verified. See there sight for pics on the install. It's my bike.unk:

 

[daholtke]

Weight actually has negligible effect on top speed (to a point of course) Top speed (when not limited by RPM) boils down the battle of HP against aerodynamic drag.

The HP goes up exponentially as speed increases. To go from 40 MPH to 80 MPH actually requires 8 times the horsepower.
The calculation is: HP = (Cd * A * (V^3))/150,000 Where Cd = Drag Coefficient, A = Frontal area, and V = Velocity.

Now, our Poor SV has 2 thing going against it
1) Drag. The naked or semi naked styling of the bike has much more drag than a full faring bike. I don't have the numbers for this, but I'd assume that the aerodynamics of the SV are pretty bad when compared to say the Hayabusa.
2) HP. Our Vtwins have physics working against them because the big pistons just can reach the RPM's of an I4 Now of course many things affect horsepower, but generally max RPM and HP are proportional (look at formula 1 cars)

So the SV just is not the bike for top speed, even though it has a 1000cc engine. But for what it was built for (torque) it does a great job. And since acceleration IS affected by mass (F=ma). The SV's high torque engine is actually better for larger riders than an I4 that has higher horsepower but has less torque. So in realtiy, although it may not get you to 170 mph, It will get you 100 faster than most other bikes of equal displacement.

 

[jrl305]

Take a look at your dyno print out. Your hp probably peaks out at 9500 rpm or so. With the 16t sprocket, you might be running out of steam. Try it with the 17 and see. Also, the tach is a little off. At 11,000 on the tach, you're only really turning 10,000, That was proven to me by all of the dyno runs that I've been on.

Try it with the 17t and see if you can squeeze out a couple more mph.

John

 

[Kyoseki]

He's also running a 16T sprocket up front (saw the same post on socalSVriders), that's going to make you hit redline long before you top out the horsepower.

When gearing your bike you have 6 horsepower curves that correspond to different ground speeds, you also have a curve that represents the horsepower required to overcome aerodynamic drag at a specific ground speed.

Where the horsepower curve in 6th intersects that aerodynamic drag curve is your bikes theoretical top speed, unless you're banging off the rev limiter at a lower speed.

You want the peak of the 6th gear horsepower curve to intersect the aerodynamic drag curve, that way you're getting max horsepower out of the engine at the right rpm, gearing down your bike moves all these curves further to the left on the graph (you hit max horsepower sooner), which is great for acceleration but does you no good if your 6th gear curve never reaches the aerodynamic curve because you ran out of rpms.

 

[elp_jc]

Several things. FIrst of all, you weigh half the bike, so that has something to do with it. Not a lot, but there's a reason racers are light.
Second, I agree with the above post: the SV engine peaks at 9K even, and torque peaks at 7.5K. Beyond 9K, you're actually slowing the bike down, even though it has 2K rpm to go ('overrev' capability).
Your speedo is an extra 6% off due to the sprocket change. It's still ridiculously off (17 - 6 = still 11% off), however.
You're going to achieve a higher top end with stock gearing, but as folks here have told you, there's a compromise for everything. Your acceleration will suffer as a result. You have to make a choice.
Finally, a twin revving to 11K is a darn accomplishment. Even the racier RC51 signs off at 10K, with identical dimensions (I believe).
And top speed has nothing to do with rev limit either. Many cars can reach close to 180 mph with 6K+ rpm redlines (especially pushrod motors). What's true is smaller motors need to rev higher to make the power, but still going to be very low in torque, and torque is what gets you out of the hole. I much prefer a torquey engine than a high-strung one, like a 600.
Think what your priorities are, and buy what suits them. Good luck.
JC

 

[daholtke]

Several things. FIrst of all, you weigh half the bike, so that has something to do with it. Not a lot, but there's a reason racers are light.......

Actually mass has little effect on top speed, it does effect how fast you get to the top speed (acceleration) The only effect weight has on top speed is a slight increase in rolling resistance. But the rest of your arguments about HP are correct.

 

[Kyoseki]

Actually mass has little effect on top speed, it does effect how fast you get to the top speed (acceleration) The only effect weight has on top speed is a slight increase in rolling resistance. But the rest of your arguments about HP are correct.

Very true, but bigger riders have a larger frontal area and so the aerodynamic drag will increase linearly with body size, it's not just about rolling friction.