If you could have one bike... | Page 4 | GTAMotorcycle.com

If you could have one bike...

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Way back in 2000 Ducati ruled WSB. MOSTLY because WSB allowed 750cc for three or more cylinders and 1000cc for two cylinder... so Ducati twins had 33% more displacement than anyone else on the grid.
Ducati won a lot of races.
Honda didn't like that.
Honda ran the RC51 in 2001, and won the championship.
IIRC Bayliss won the 2002 championship, but he would have won it on a ten speed.
In 2003 WSB changed the rules to 1000cc for everyone, Honda went back to a 4 cylinder and Ducati floundered.
Those were good years for WSB. Bayliss and Fogarty on Ducatis and Hayden, Edwards and DuHamel on Hondas. Made for some great racing.
Honda won a lot more races since.
 
bitzz said:
In 2003 WSB changed the rules to 1000cc for everyone, Honda went back to a 4 cylinder and Ducati floundered.
Click to expand...

Then in 2008, Ducati had a crying fit and said if the rules didn't change back, that they'd take their ball and go home. So the FIM had to let Ducati have 1200ccs for their twins. Been that way ever since.
 
Ducati is now a 1000cc V4 in moto GP
For 2020.
I think desmo is helping produce more hp.

This should be an exciting year.

Honda is struggling. Yamaha looks good Suzuki is a contender.
KTM is strong.

We may even see Aprilla on the podium.
 
Ducati has been using their 1L V4 for a few seasons now, no? They've been the kings of top speed since.
 
yes, that Duc V4 has been around for a bit
Desmo is probably a factor
but they just plain get more HP out of 1000 cc than anyone else currently
I think they have have the TC/electronics working pretty well too
 
"Desmo" was a good idea when it came out in the 1930's on an Auto-Union race car.
"Desmo" was a good idea when Taglioni used it on his engines in the mid 1960's.
Advances in metallurgy in the last 50 years have negated any advantages that "desmo" had.
In the present day "desmo" is a gimmick that sells motorcycles. THERE IS NO PERFORMANCE GAIN IN "DESMO". NONE.
In the present day all "desmo" adds is unnecessary cost and complexity to Ducati motorcycles... but it sounds cool. There are LOTS of motors with valve springs that will out rev a Ducati. Honda could make a 16-17,000 RPM engine in the 1960's.

... and an old racing maxim: No one has ever won a race on a dyno.
It takes more than straight line speed to win races.
 
bitzz said:
"Desmo" was a good idea when it came out in the 1930's on an Auto-Union race car.
"Desmo" was a good idea when Taglioni used it on his engines in the mid 1960's.
Advances in metallurgy in the last 50 years have negated any advantages that "desmo" had.
In the present day "desmo" is a gimmick that sells motorcycles. THERE IS NO PERFORMANCE GAIN IN "DESMO". NONE.
In the present day all "desmo" adds is unnecessary cost and complexity to Ducati motorcycles... but it sounds cool. There are LOTS of motors with valve springs that will out rev a Ducati. Honda could make a 16-17,000 RPM engine in the 1960's.

... and an old racing maxim: No one has ever won a race on a dyno.
It takes more than straight line speed to win races.
Click to expand...
I will have to research your point to argue against it.
Having the valves positively opened and closed has to be an advantage. No valve float has got to be better than valve springs.
Will get back to you.
 
Low rider said:
I will have to research your point to argue against it.
Having the valves positively opened and closed has to be an advantage. No valve float has got to be better than valve springs.
Will get back to you.
Click to expand...

A very interesting tidbit I found on my trek. Also check the link for the Koeningsegg free valve.
 
bitzz said:
"
In the present day "desmo" is a gimmick that sells motorcycles. THERE IS NO PERFORMANCE GAIN IN "DESMO". NONE.
In the present day all "desmo" adds is unnecessary cost and complexity to Ducati motorcycles... but it sounds cool. There are LOTS of motors with valve springs that will out rev a Ducati. Honda could make a 16-17,000 RPM engine in the 1960's."
Click to expand...

Well, if springs alone would be good enough why do no MotoGP teams use springs only? They either use a pneumatic assisted spring or the Desmo.

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Springs cause "float" at high rpms and this leads to inconsistent "charge" and "extraction", the desmo arrangement allegedly avoids this. Am not a bike engineer and am open to correction on this.

"four wheels good, two wheels better"
 
Good morning :) what are we discussing today; ah yes, the pros and cons of poppet valves?
read, read, read, :unsure: moot point but I think the difference between 1000cc and 750cc is 25% not 33%

"Having the valves positively opened and closed has to be an advantage"
Having the valves positively opened and closed is way more then that it is a critical requirement!
They also need to seal well when they are closed, they can not slam shut or you will break them and if you make the whole thing run too tight with heavy duty springs you lost some performance through friction. The valves need to follow the cams at all times. So IF your valve train design is prone to valve float you have a choice, install bigger stiffer springs and that has obvious friction and wear problems, lighten the moving parts so they have less inertia (the true source of valve float), or mechanically force the valve to follow the cam with something like the Desmo valve train design. It's not rocket science :geek: it's about as complicated as a sewing machine.
 
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Chris-CJ said:
Springs cause "float" at high rpms and this leads to inconsistent "charge" and "extraction", the desmo arrangement allegedly avoids this. Am not a bike engineer and am open to correction on this.

"four wheels good, two wheels better"
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Desmos do have springs (clothespin style) they wouldn't start or idle very well without them.
Ducs are making huge power for more reasons than desmo.116x80.6 bore and stroke and very fine attention to detail in the cylinder head ports.
 
All Moto GP bikes have pneumatic valves being closed with nitrogen from a refillable tank carried on board. So Desmo is no longer an advantage.
 
Low rider said:
All Moto GP bikes have pneumatic valves being closed with nitrogen from a refillable tank carried on board. So Desmo is no longer an advantage.
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That's about like saying; they make turbine engines and electric motors now so reciprocating piston engines are obsolete.
 
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To begin with, we are talking about making a poppet valve on an internal combustion engine work better, when a better solution would be to come up with something better then a poppet valve :geek:
Low rider said:
All Moto GP bikes have pneumatic valves being closed with nitrogen from a refillable tank carried on board. So Desmo is no longer an advantage.
Click to expand...
You won't run out of Desmo but you might run out of compressed nitrogen :unsure:

btw: there really was a Ducati sewing machine.
 
bitzz said:
"Desmo" was a good idea when it came out in the 1930's on an Auto-Union race car.
"Desmo" was a good idea when Taglioni used it on his engines in the mid 1960's.
Advances in metallurgy in the last 50 years have negated any advantages that "desmo" had.
In the present day "desmo" is a gimmick that sells motorcycles. THERE IS NO PERFORMANCE GAIN IN "DESMO". NONE.
In the present day all "desmo" adds is unnecessary cost and complexity to Ducati motorcycles... but it sounds cool. There are LOTS of motors with valve springs that will out rev a Ducati. Honda could make a 16-17,000 RPM engine in the 1960's.

... and an old racing maxim: No one has ever won a race on a dyno.
It takes more than straight line speed to win races.
Click to expand...
I think Desmo is kept in Ducati’s for the same reason HD keeps pushrods and air cooling— purely nostalgia and heritage for their loyal base.

Now, the argument might be different if you are shopping for a MotoGP race bike, I could understand splitting hairs between nitro and desmo valve train. But if you bring the argument back to the bikes Ducati builds for the road, the argument changes -- alot. Desmo is not going to provide any performance, reliability, or TCO advantage to your cruiser, street, or ADV bike, I would argue the frequency, technical difficulty and cost of maintaining a desmo system provides a significant downside.
 
Trials said:
To begin with, we are talking about making a poppet valve on an internal combustion engine work better, when a better solution would be to come up with something better then a poppet valve :geek:

You won't run out of Desmo but you might run out of compressed nitrogen :unsure:

btw: there really was a Ducati sewing machine.
Click to expand...
1583419579863.png
The first all electric Ducati was a sewing machine.
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