MotoGP 2012

[pritch]

This article is translated from the Italian so in places the language is a bit ummm unusual(?).

http://manziana.motocorse.com/blog/32890_Desmo-whys

[roogazza]

This article is translated from the Italian so in places the language is a bit ummm unusual(?).
http://manziana.motocorse.com/blog/32890_Desmo-whys

Cheers pritch, interesting stuff, thanks.

[Brian d marge]

Very good article , basically what Ive been saying all along ( cant be arsed finding old posts ,,,someone else can) , ,,the ducati has some fundamental design problems , the shape of the engine , which causes the design to more away from the optimal

Ive also mentioned Honda Data base , its HUGE and based on countless fk ups and u cant get near it ! so they arnt gods gift to engineers they just made a hell of a lot of cock ups !!!

Also one thing I thought about , is the lugana seca engine ...where is it ? not happening? ( mask the cornering probs by brute power )

One thing I didnt see , think of , is the swing arm , you rotate the engine to move the cog , down and forward , the sprocket moves away from the swing-arm pivot ( they should be on the same plane ) ,,,so , to keep them close , the swing-arm lengthens ( great pics thanks) and that has inertia , etc

If Ducati sort this and keep the L config , seriously impressed ,,would I be

Hats of to Hayden and Rossi who had to ride the thing ......

Stephen

[Drew]

One thing I didnt see , think of , is the swing arm , you rotate the engine to move the cog , down and forward , the sprocket moves away from the swing-arm pivot ( they should be on the same plane ) ,,,so , to keep them close , the swing-arm lengthens ( great pics thanks) and that has inertia , etc

Mount the swing arm pivot throught the output shaft. PERFECT position all the time, as opposed to the current system which is only spot on at a single swing arm angle.

Dunno why this isn't done.

[denill]

Mount the swing arm pivot throught the output shaft. PERFECT position all the time, as opposed to the current system which is only spot on at a single swing arm angle.

Dunno why this isn't done.

Absolutely! There are some past examples (Can't remember the Maques tho) but why it's not universal defies logic IMO.

[merv]

Absolutely! There are some past examples (Can't remember the Maques tho) but why it's not universal defies logic IMO.

Amount of bracing required probably and nowhere to put it.

[denill]

Mount the swing arm pivot throught the output shaft. PERFECT position all the time, as opposed to the current system which is only spot on at a single swing arm angle.

The swing arm pivot does not of course need to go through the output shaft. Just as long as the centre of the pivot is the same as the centre of the output shaft.

[denill]

Absolutely! There are some past examples (Can't remember the Maques tho) but why it's not universal defies logic IMO.

Husqvarna: CTS - Coaxial Traction System - http://www.husqvarna-motorcycles.com...1#!/highlights

[Crasherfromwayback]

Mount the swing arm pivot throught the output shaft. PERFECT position all the time, as opposed to the current system which is only spot on at a single swing arm angle.

Dunno why this isn't done.

There's nothing wrong with seperating the various forces involved. Just gotta control them better that the next fucker.

And moto-x bikes are the perfect example. Nothing wrong with a swingarm going through it's arc if the swingarm pivot vs the front countershaft is correct.

[Brian d marge]

There's nothing wrong with seperating the various forces involved. Just gotta control them better that the next fucker.

And moto-x bikes are the perfect example. Nothing wrong with a swingarm going through it's arc if the swingarm pivot vs the front countershaft is correct.

Dont come back in the next life as a chain on a mx bike then ....

Stephen

[slowpoke]

This article is translated from the Italian so in places the language is a bit ummm unusual(?).

http://manziana.motocorse.com/blog/32890_Desmo-whys

Great find Pritch, one of the best articles I've read relating to the current predicament Ducati/Preziosi find themselves in. I admit to wondering why the hell Preziosi still had a job, but this fills in a few blanks. The Audi deal might help them long term but if anything it has hurt them with delays this season.

[Crasherfromwayback]

Dont come back in the next life as a chain on a mx bike then ....

Stephen

Dude. Early MX bikes caned them. By the late 70's early 80's they moved the s/a pivot that close to the countershaft they'd all but fixed the issues that go with it. It's often the height between that s/a pivot and the c/s that needs changing to get better results now no?

Hence why countershaft through s/a pivot ain't the answer. If it was...I think those very clever wee Japanese fellows would be doing it too.

[denill]

Hence why countershaft through s/a pivot ain't the answer. If it was...I think those very clever wee Japanese fellows would be doing it too.

I can't accept it's not the answer. In fact I consider it''s the ultimate solution.

[Brian d marge]

Dude. Early MX bikes caned them. By the late 70's early 80's they moved the s/a pivot that close to the countershaft they'd all but fixed the issues that go with it. It's often the height between that s/a pivot and the c/s that needs changing to get better results now no?

Hence why countershaft through s/a pivot ain't the answer. If it was...I think those very clever wee Japanese fellows would be doing it too.

They didnt fix it , they just masked the problem , with a guide and wheel , essentially you have two arcs and at one point will those align, the more rear wheel or greater disparity between those arc the worse the chain suffers , what is a modern MX bike , over an inch slack WITH tensioning wheels

I think BMW are one maker that have managed to align the two , The worst design was the plunger set up


Stephen

[Drew]

The chain suffering is not the problem. The distance between the sprockets changes with the swing arm in different positions, so the engine is fighting the suspension going through it's travel at some point. By making swing arm pivot and sprocket center the same, there is so much more control available it aint funny.

When I say mount the pivot through the output shaft, I mean on the same axis. Not trying to put a bolt through the shaft, although that would work pretty easily.

But I'm no engineer, there might be a reason it isn't done.