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General Category => General Discussion => Topic started by: not-fishing on March 02, 2015, 11:10:29 AM

Title: 1975 750S --why can't Guzzi do 70 hp now?
Post by: not-fishing on March 02, 2015, 11:10:29 AM
Depending on where you look the Crank horsepower is 70-90 back in 1975.

Why can't Guzzi do it now with all the whiz-bang-computer technology and advances in the last 35 years?   

Is it the gasoline is not as good?

and I admit when I had hair I was a blond it this question seems a little dumb

Mark
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: LowRyter on March 02, 2015, 11:12:05 AM
you're comparing the small block heron head to the big block hemi.

Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Lannis on March 02, 2015, 11:15:14 AM
Depending on where you look the Crank horsepower is 70-90 back in 1975.

Why can't Guzzi do it now with all the whiz-bang-computer technology and advances in the last 35 years?   

Is it the gasoline is not as good?

and I admit when I had hair I was a blond it this question seems a little dumb

Mark

If the "where you look" included the Motorcycle Magazines of the times ... they used to lie like big dogs about "horsepower"; I get the impression they would measure it at the rear wheel, extrapolate it to the piston crown, and report THAT as the "horsepower".

On the other hand, no one makes a gasoline-engined car any more like my 1990 Kia/Ford Festiva (Mazda 121) that gets 44 MPG overall, either, so maybe a combination of modern heavier weights and bad gasoline is part of the culprit ....

Lannis
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: mgfan on March 02, 2015, 11:24:16 AM
I think they were using slide rules to compute block hp and rounding up by 15.    :BEER:
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: oldbike54 on March 02, 2015, 11:30:01 AM
 In the 60s an English moto journalist asked the Montesa importer haow much power their new 250 MXer made .
He asked "How much is Bultaco claiming , our's makes one more"  ::)
 
  Dusty
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Antietam Classic Cycle on March 02, 2015, 11:49:43 AM
Depending on where you look the Crank horsepower is 70-90 back in 1975.

That "70 hp" is/was actually around 50-55 hp at the crank.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: pyoungbl on March 02, 2015, 11:56:12 AM
I suspect we could get 75 hp at the crank if we bumped the displacement up to 830-850cc and replaced the Heron heads with something that allowed better breathing.  Ed Milich is the guy to ask.

Peter Y.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: guzzisteve on March 02, 2015, 11:56:34 AM
you're comparing the small block heron head to the big block hemi.


This,  Small bock (Heron Head) is no match for Big Block, it was designed to be a 350 & 500cc. Even the 4V and 2V Hemi head stuff is prone to blow up if you don't shift 1K rpm before redline. Even the drivetrain is small contact area's. It's ASS CANDY for the marketing part of the company.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: sib on March 02, 2015, 12:55:48 PM
The reason why small block Guzzis have Heron heads is because they are best for the job they are called to do.  Small block Guzzi buyers don't want to go 150 mph.  They want even, high torque over a wide rpm range, non-finnicky fuel requirements, long engine life, and relatively low cost.  My '13 V7 Stone will go 110 mph.  What would 20 more hp give me?  125 mph?  Dandy.  If I needed to go faster than 110, I'd opt for a different bike and make sure my living will is in good order.  I'd then be trading increased hp for increased problems.  No thanks.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: rocker59 on March 02, 2015, 01:07:05 PM


70 BHP   (brochure horse power)    :BEER:



Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Gliderjohn on March 02, 2015, 02:39:31 PM
To help be realistic My T-3 is a big block of course but even punched out to 1,000cc and other significant mods it's RWH on a dyno measured out at 56hp and 54 pounds of torque. Runs real nice for an older Guzzi however. ;-T
GliderJohn
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Vasco DG on March 02, 2015, 03:37:09 PM
To help be realistic My T-3 is a big block of course but even punched out to 1,000cc and other significant mods it's RWH on a dyno measured out at 56hp and 54 pounds of torque. Runs real nice for an older Guzzi however. ;-T
GliderJohn

Which sounds about par for the course. Stock 948cc Smallvalve engine makes around 45-46 with 30mm VHB's and *Unobtrusive* pipes.

Pete
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: huub on March 02, 2015, 03:38:47 PM
i've had three V7sports on the dyno, never seen more than 50 hp.
having said that , a smallblock probably struggles to reach 40 hp.
i have had quite a lot of trouble getting the clutch to last on my v65tt, i dont think a smallblocks drivetrain would last very long with a  a real 50 hp.

having said that , it would be fun to try , as much power as the V7sport with 50 kilo less should be enough to annoy loads of big bikes on twisty roads
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Rough Edge racing on March 02, 2015, 03:44:12 PM
If the "where you look" included the Motorcycle Magazines of the times ... they used to lie like big dogs about "horsepower"; I get the impression they would measure it at the rear wheel, extrapolate it to the piston crown, and report THAT as the "horsepower".

On the other hand, no one makes a gasoline-engined car any more like my 1990 Kia/Ford Festiva (Mazda 121) that gets 44 MPG overall, either, so maybe a combination of modern heavier weights and bad gasoline is part of the culprit ....

Lannis
 
  Yeah, the bike magazines like to use the Dynojet because it inflates power figures.....And is the least expensive dyno...Although no dyno is cheap.
  Somewhere in the late 1990's emission standards tightened requiring a specialized 3 way  catalyst convertor on cars and some light trucks. To work properly the 3 way convertor needs a  Stoichiometric fuel mixture of 14.7 at part throttle. Your older vehicle can operate on leaner mixtures around 16-1. Can't be the gas because you're using the same gas as newer vehicles...
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Dilliw on March 02, 2015, 04:25:44 PM

On the other hand, no one makes a gasoline-engined car any more like my 1990 Kia/Ford Festiva (Mazda 121) that gets 44 MPG overall, either, so maybe a combination of modern heavier weights and bad gasoline is part of the culprit ....

Lannis

Modern cars can still perform while putting up with all the safety regulations.

Your Festiva has 73hp, weighs 1750 and if you are doing better than the EPA est of 37mpg then good for you.
http://www.edmunds.com/ford/festiva/1990/features-specs.html

My Mazda3 has 150hp, weighs 2969lbs, and I average 35mpg plus get over 40mpg on most trips.
http://www.edmunds.com/mazda/mazda3/2012/st-101413981/features-specs/


Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: guzziownr on March 02, 2015, 04:42:38 PM
To help be realistic My T-3 is a big block of course but even punched out to 1,000cc and other significant mods it's RWH on a dyno measured out at 56hp and 54 pounds of torque. Runs real nice for an older Guzzi however. ;-T
GliderJohn

Dang, I only got 55.  What was Mike Rich's phone #?  I had it here someplace...
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Rough Edge racing on March 02, 2015, 04:45:56 PM
 My 51 Willys 4x4 truck has 71 HP gross hp ,weighs 3150 lbs on the scale and gets about 15 mpg and has a cruising speed of about 45 mph with the stock 5.38 gears.  ;D

  
  
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Gliderjohn on March 02, 2015, 05:03:36 PM
Quote from guzziowner:
Quote
Dang, I only got 55.  What was Mike Rich's phone #?  I had it here someplace...

HA! HA! Beat you by one. ;D
GliderJohn
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: cruzziguzzi on March 02, 2015, 05:09:57 PM
you're comparing the small block heron head to the big block hemi.



I know it's apples-oranges and... other kinds of oranges but:

Where does the Lario fit in? Small block sure, but better head performance.

Todd.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Greg Field on March 02, 2015, 11:20:45 PM
Good lord.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Penderic on March 03, 2015, 04:54:39 AM
Oh Boy! And get 70 miles per gallon, and weigh less, and cost the same, and .......

(http://i1299.photobucket.com/albums/ag77/Penderic/rainbow_zpsgh1qbqhk.jpg)


 ~;

Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: lucydad on March 03, 2015, 05:50:18 AM
This one goes to 11.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Rough Edge racing on March 03, 2015, 06:27:04 AM
To help be realistic My T-3 is a big block of course but even punched out to 1,000cc and other significant mods it's RWH on a dyno measured out at 56hp and 54 pounds of torque. Runs real nice for an older Guzzi however. ;-T
GliderJohn

Interesting,my 650 Triumph race bike on a Superflow dyno makes 55 rear wheel HP @7300 rpm ,45 ft lbs of torque at 5100 rpm. The engine isn't too radial,starts on one kick and idles steady with a lope at 1000 rpm. The Triumph is a 1930's design with all the limitation of vintage British engine. I know dyno readings can't be compared but I would think a modified 1000 Guzzi hemi head would make a lot more power......
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Cheese on March 03, 2015, 06:47:49 AM
Interesting,my 650 Triumph race bike on a Superflow dyno makes 55 rear wheel HP @7300 rpm ,45 ft lbs of torque at 5100 rpm. The engine isn't too radial,starts on one kick and idles steady with a lope at 1000 rpm. The Triumph is a 1930's design with all the limitation of vintage British engine. I know dyno readings can't be compared but I would think a modified 1000 Guzzi hemi head would make a lot more power......

What's the difference in losses between chain to shaft final drive as tested on a rolling road? Couple horses there. What modifications? As you said, different dynos too. Every little thing matters. And it's tough for the average Joe to measure at the crankshaft. I like to ride the torque personally so HP is not that important to me. Also, manufacturers lie about horsepower because it's so easy to mess with the measurement parameters. How much does your bike weigh? Well, what's included? Look at what recently happened with garden equipment. Big kerfuffle over HP. No more HP figures quoted now but just cubic volume. Always a good topic!

Peter
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: huub on March 03, 2015, 06:56:34 AM
Interesting,my 650 Triumph race bike on a Superflow dyno makes 55 rear wheel HP @7300 rpm ,45 ft lbs of torque at 5100 rpm. The engine isn't too radial,starts on one kick and idles steady with a lope at 1000 rpm. The Triumph is a 1930's design with all the limitation of vintage British engine. I know dyno readings can't be compared but I would think a modified 1000 Guzzi hemi head would make a lot more power......

i have seen a v7sport tuned to over 90 hp, at wich point it ran at close to 10.000 rpm , and blowups were pretty predictable.
As you probably know getting power is one thing , getting it reliable enough for a roadbike is another.
i dont think commuting on you racing triumph would be a good idea
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 03, 2015, 07:16:50 AM
I know it's apples-oranges and... other kinds of oranges but:

Where does the Lario fit in? Small block sure, but better head performance.

Todd.

Ahh... about 38hp at the tire. My Milich Lario all tarted up is 44hp @the wheel. It's a light bike (and mine's even lighter) so it's pretty zippy.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Gliderjohn on March 03, 2015, 09:04:21 AM
My T-3 three mods were:
1,000 cc kit
36mm round slides
Port and polished heads
V-7 sport cam
Heavier valve and clutch springs
K&N filters
Just run cheap Emego mufflers, but they sound nice.

Nothing radical and now have around 30K miles since engine was redone anvil like reliability so far.
Here was the dyne graph:
(http://i710.photobucket.com/albums/ww107/jpeters16/DSCN0483.jpg) (http://s710.photobucket.com/user/jpeters16/media/DSCN0483.jpg.html)
GliderJohn



Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: skromfols on March 03, 2015, 09:16:17 AM
My 05 Nevada showed 38.30 hp and 35.82 tq stock and with head work, increased displacement, open intake and exhaust and a good dyno tune (with power commander) measures 51.23 hp and 50.20 tq.  I've only got about 1,500 miles on it since the engine work, but the clutch seems to be handling it with no problem.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Cheese on March 03, 2015, 09:24:58 AM
My T-3 three mods were:
1,000 cc kit
36mm round slides
Port and polished heads
V-7 sport cam
Heavier valve and clutch springs
K&N filters
Just run cheap Emego mufflers, but they sound nice.

Nothing radical and now have around 30K miles since engine was redone anvil like reliability so far.
Here was the dyne graph:
(http://i710.photobucket.com/albums/ww107/jpeters16/DSCN0483.jpg) (http://s710.photobucket.com/user/jpeters16/media/DSCN0483.jpg.html)
GliderJohn

That's a thing of beauty! I'd be riding it mostly between 3500 and 5000. Do you find the need to go higher?




Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Gliderjohn on March 03, 2015, 09:35:28 AM
Quote from Cheese:
Quote
That's a thing of beauty! I'd be riding it mostly between 3500 and 5000. Do you find the need to go higher?

Not really. Do run it up at times just for the sound of it. ;D Certainly no reason to run it above 6,500. Since it is a police model it does not have a tach so just go by sound and feel. It does have a very nice midrange and rarely have need to downshift to pass.
GliderJohn
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: frans belgium on March 03, 2015, 09:46:26 AM
having said that , it would be fun to try , as much power as the V7sport with 50 kilo less should be enough to annoy loads of big bikes on twisty roads

It doesn't need an upgrade for that.
In the twisties,  my son used to outrun me on his Nevada against my B11.
And that was in the days when I was still young enough to go fast and he was too young to outrun me on anything.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: John A on March 03, 2015, 02:25:15 PM
What Cheese and John said  is what I think too: torque is what makes it fun. When I was on a Funny car team my boss told me that "if we're not breaking parts it's because we're not making enough power" so there is that. A guy should be able to twist out a clutch hub occasionaly ;D
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 03, 2015, 04:56:08 PM
My 05 Nevada showed 38.30 hp and 35.82 tq stock and with head work, increased displacement, open intake and exhaust and a good dyno tune (with power commander) measures 51.23 hp and 50.20 tq.  I've only got about 1,500 miles on it since the engine work, but the clutch seems to be handling it with no problem.

Is this the one Milich did last year? 850cc?
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: redrider on March 03, 2015, 06:06:28 PM
The Café Sport hit 79 and change on a portable Dynojet. My friend's Griso added 10. My Norton hit 46. I personally feel there are two types of power. Real-at the crank and Real World-after all gearing changes as delivered to the drum.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: skromfols on March 04, 2015, 06:13:21 AM
Is this the one Milich did last year? 850cc?

Yes. 
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Dogwalker on March 04, 2015, 07:11:42 AM
Depending on where you look the Crank horsepower is 70-90 back in 1975.
The big block 750 have never developed 70 hp at the crank.
The real figure was of 52 hp at the rear wheel.
That can be translated (but without much sense, as the power at the rear wheel is what count) in 57/58 hp at the crank.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Dogwalker on March 04, 2015, 07:15:43 AM
Where does the Lario fit in? Small block sure, but better head performance.
51hp at the rear wheel for the Lario, 60 hp at the rear wheel for the V75 4V, all measured by the magazines of the era.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 04, 2015, 11:14:28 AM
Yes. 
Did you tell us about your experience with this bike yet?  I for one would love to hear about this bugger.  ;-T
Many others as well I'm certain.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 04, 2015, 11:15:56 AM
51hp at the rear wheel for the Lario, 60 hp at the rear wheel for the V75 4V, all measured by the magazines of the era.
Not measured by Milich 2 yrs ago. About 38 RWH.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: skromfols on March 04, 2015, 11:40:37 AM
Did you tell us about your experience with this bike yet?  I for one would love to hear about this bugger.  ;-T
Many others as well I'm certain.

I have a disagreement with Ed Milich about the project and I would prefer to wait until it's settled before providing details about the experience and the outcome.  But there is no dispute about the power and torque increase.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Dogwalker on March 04, 2015, 11:46:39 AM
Not measured by Milich 2 yrs ago. About 38 RWH.
I understand your point, but on the bench of Milich had been measured some bike. On the Bench of Motociclismo and In Moto had been measured all the motorcycle production of the last 35 years (and more), and the data measured 30 years ago are consistent with those measured today, so, if I want to do a comparison, I have to use the benches of the magazines.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 04, 2015, 12:18:44 PM
I understand your point, but on the bench of Milich had been measured some bike. On the Bench of Motociclismo and In Moto had been measured all the motorcycle production of the last 35 years (and more), and the data measured 30 years ago are consistent with those measured today, so, if I want to do a comparison, I have to use the benches of the magazines.

Interesting perception.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: Chuck in Indiana on March 04, 2015, 12:40:37 PM
Interesting perception.

Well, Ed's dyno reads low. When he dynoed your original motor I remember seeing the pix of the teardown. One valve was seriously burnt, and I'd be surprised if that cylinder had *any* compression. At any rate, no matter the number, you got a 15% increase.
Title: Re: 1975 750S --why can't Guzzi do 70 hp now?
Post by: kevdog3019 on March 05, 2015, 06:52:50 AM
Well, Ed's dyno reads low. When he dynoed your original motor I remember seeing the pix of the teardown. One valve was seriously burnt, and I'd be surprised if that cylinder had *any* compression. At any rate, no matter the number, you got a 15% increase.
I'm not trusting any of those numbers Chuck. There were so many issues and attempts with the final dyno that we simply can't say what I ended up with,  The original 38 I can't vouch for. I doubt there was a leak down performed. I can only vouch for the difference between my stock Lario which has new valves and good compression and my hopped up job. BIG difference.