theoretical top speed in 6th gear

[MMRanch]

So , being as the V-7 has a speedometer and a tachometer , and being gear/speed relationship is a linear equation , then it is easy to calculate that at 7,000 RPM in 6th gear the speedometer would be reading twice the speed it reads at 3,500 RPM in 6th gear ... which is 59 MPH - or 118 MPH @ 7000 RPM.

So , does anybody know what the theoretical top speed of a V-9 is ?   Or one of the other versions of the 850 Guzzi ?

 

   

[Huzo]

So , being as the V-7 has a speedometer and a tachometer , and being gear/speed relationship is a linear equation , then it is easy to calculate that at 7,000 RPM in 6th gear the speedometer would be reading twice the speed it reads at 3,500 RPM in 6th gear ... which is 59 MPH - or 118 MPH @ 7000 RPM.

So , does anybody know what the theoretical top speed of a V-9 is ?   Or one of the other versions of the 850 Guzzi ?

 

You correctly state that the increase in velocity vs RPM is linear but resistance to forward motion varies with the square of your velocity.
Therefore, only a small increase in wind resistance due to parasitic drag will have a large effect on your achievable speed. To go ahead and state a theoretical top speed, you would have to standardise a few other variables like mass, wind, drag, blah blah...
Grab a demo model, take it out on a calm day, crawl under the paint on the tank and hold the throttle flat until it stops getting louder...
Then you'll know.

[MMRanch]

And don't forget rear tire slippage as it fight to push the bike into the wind too.

On my other bikes the speedometer is driven off the transmission so the front wheel speed and the pushing rear wheel could have different speeds .....
ya think that might mess with the traction control system ?

I was looking for 70 mph high gear RPM ... of the Guzzi 850 bikes

[Rough Edge racing]

 I've learned from land speed racing my Triumph junk and watching other bikes that it takes about 45-50 HP at the rear wheel to push a naked frame bike to about 120MPH in a 1-1/2 mile run from a standing start on pavement...This assumes the rider is able to achieve a proper riding position...

[Fontain25]

1978 BMW R100S same top speed in 4th or 5th gear. Honda NX650, geared as tall as possible as per customer request; same top speed. So it seems like X amount of HP = Ymph.

[Huzo]

1978 BMW R100S same top speed in 4th or 5th gear. Honda NX650, geared as tall as possible as per customer request; same top speed. So it seems like X amount of HP = Ymph.

Power is = torque x RPM.
(Like a constant speed prop on a 'plane.)
If you drop from 5th back to 4th in the case of the Beemer, you're raising your RPM so you'll consequently need less torque for the equation to balance out to the same power figure.
If you were on your peak torque figure when in 5th at top speed, then changed to 4th, you've dropped away from the "fattest" part of the curve but increased RPM, so the multiple of the two is the same as before, therefore in your case you've been able to maintain the same power. ie, top speed.

[MMRanch]

First time I played with gearing change was with an old KZ750 (4cylinder/double overhead cam) Kawasaki .

So 5th gear redline was about 115mph and the bike would almost do it , mpg at best was 42 mpg.   I changed sprocket (front+rear) to be a theoretical 165mph. 5th gear red line .     The  average mpg went to  53  , and the 70-75 mph runs on the super slab went a lot smoother .   

Now the bike wouldn't run any faster and that's not what I'm asking .  Kind of like my wifes Chevy Impala has a theoretical top speed of 280 mph and cruses at 70 mph at 1500 rpm and get over 30 mpg. local .   I don't think there is a hill long enough ... 

Question is :  On Guzzi's 850 class bike's what RPM = 70 mph ?

[guzzisteve]

5 speed w/  7/33 is 4Krpm @ 70mph in 5th

There is a gearing chart in the back of LM2 LeMans Service Manual
along w/Hop-Up kit info.

[troyhamilton]

First time I played with gearing change was with an old KZ750 (4cylinder/double overhead cam) Kawasaki .

So 5th gear redline was about 115mph and the bike would almost do it , mpg at best was 42 mpg.   I changed sprocket (front+rear) to be a theoretical 165mph. 5th gear red line .     The  average mpg went to  53  , and the 70-75 mph runs on the super slab went a lot smoother .   

Now the bike wouldn't run any faster and that's not what I'm asking .  Kind of like my wifes Chevy Impala has a theoretical top speed of 280 mph and cruses at 70 mph at 1500 rpm and get over 30 mpg. local .   I don't think there is a hill long enough ... 
does your wife have jato rockets? like on mythbusters?
Question is :  On Guzzi's 850 class bike's what RPM = 70 mph ?

[Kev m]

Uh guys, everyone knows the top speed of a smallblock is terminal velocity.

[twowheeladdict]

Depending on how the bike is geared, but typically top speed is achieved in a lower gear than top gear.  All the bikes I have tried this with backed my statement as well as what others have reported. 

I have never tried to attain top speed on the Café Classic, but I have done the ton just to see what it feels like on this style bike.  Let me say it is a lot scarier than on bikes designed to go 150 or higher.

[MMRanch]

CRUSE-ABILITY   

Not , TOP SPEED

Thanks Steve , That is exactly what I was looking for ... 
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TwoWheelAddict

I believe mine would go faster in 5th than 6th    and  70mph cruise happens about 4100 rpm. in 6th gear.  So I'm guessing the V-9 set-up is geared just like the V-7 set-up .   




 

[dcardo021]

CRUSE-ABILITY   

Not , TOP SPEED

Thanks Steve , That is exactly what I was looking for ... 
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TwoWheelAddict

I believe mine would go faster in 5th than 6th    and  70mph cruise happens about 4100 rpm. in 6th gear.  So I'm guessing the V-9 set-up is geared just like the V-7 set-up .   

I ran my V9 up to an indicated 115 mph with a,slight down hill.

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[MMRanch]

So dcardo021

Did ya run out of RPM ?
or
Did ya hit the rev. limiter
or
Did ya run out of power

What do ya think stopped it from going on ?

 

[mtiberio]

I ran my "lemans" style Guzzi big block at El Mirage dry lake for 6 events this year. My fastest with no fairing was 142 MPH, and my best with a Lemans style 1/4 fairing was 140. Many factors contribute to that seeming contradiction. I estimate that my bike made 63 HP at the rear wheel at the altitude of the dry lake (2800 feet). YMMV. My gearing spreadsheet says with no slip, you would pull ~141 on a Lemans 1 at 7750 RPM with a standard 5 speed, 7:33 and 120/90-18 rear tire.

[MMRanch]

mtiberio

140 mph @ 7750 rpm / 2 = 70 mph @ 3875 rpm ...  that's  not much difference than the V-7 gearing ...

Thanks for the end put ! 

I was guessing that a 74mm stroke should run close to 8000rpm redline  but on a V-7  6th gear redline  is surely THEORETICAL ... 

[dcardo021]

So dcardo021

Did ya run out of RPM ?
or
Did ya hit the rev. limiter
or
Did ya run out of power

What do ya think stopped it from going on ?

 

I just stopped at that speed. Bike was working pretty hard with my luggage. Never saw the red light flashing for red line. Great little bike, punches above its weight class in my opinion

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