When was the last time Mamola was on anything resembling a factory GP bike? I guarentee that he wouldn't turn one lap near any current riders time let alone Nicky,Rossi ,Stoner, Melandri, etc...
Mamola and schwantz took out the 990 rizla suzukis at valencia last yr and turned laps within 3 seconds of hopkins/vermeulens race pace.
Thank you for being man enough to stand corrected, and for not being too offended by my tone. I'm trying to be nicer.
Quote:
Originally Posted by DucatiDom
247 thank you for the informative reply, if he is current with the bikes then his opinion has more validity than a guy that hasn't ridden current race technology in the past ten years. I stand corrected on Mamola.
2.5 seconds slower per lap=race finsish approximately 1 minute behind either of those guys. My point was if you haven't ridden a GP bike recently your opinion has less validity. I don't doubt the talents of Mamola or Schwantz, they both made the big show. I just can't abide by someone who hasn't ridden in years, or never ridden a GP bike saying that it is as simple as a set of tires, or having the same bike and any particular rider(Rossi) could have beaten another(Stoner).There are to many other factors that have to be considered.
There are to many other factors that have to be considered.
I'd wager that rather than factors that need to be considered, there are too many factors which are unknowns to the public at larger (regardless of how "informed" the fan may think he/she is) to give any of these discussions even the slightest modicum of validity.
I'd wager that rather than factors that need to be considered, there are too many factors which are unknowns to the public at larger (regardless of how "informed" the fan may think he/she is) to give any of these discussions even the slightest modicum of validity.
I can't argue with that....although I never really thought of myself as being among the "public at larger....."
I'd wager that rather than factors that need to be considered, there are too many factors which are unknowns to the public at larger (regardless of how "informed" the fan may think he/she is) to give any of these discussions even the slightest modicum of validity.
Agreed... all I know is that Rossi's M1 fairings are 2 inch wider and it's
crankshaft weights more than the Ducati...
Agreed... all I know is that Rossi's M1 fairings are 2 inch wider and it's
crankshaft weights more than the Ducati...
Larry, you KNOW this...as in you have independently measured numbers? Care to share them - actual measured fairing widths for both, and the crank weights?
I'm REAL intrigued as to where and you you got the numbers, as you must have incredible contacts/access to very secret engine details from competing teams that are NEVER published or allowed to be measured by anyone other than a race team engineer.
I'm REAL intrigued
__________________ Old Baldy / WWBO #451
Ducati 996
Kawasaki KLR 650 '02
Kawasaki KLR650 '06 OB's Blog
Larry, you KNOW this...as in you have independently measured numbers? Care to share them - actual measured fairing widths for both, and the crank weights?
I measured the M1 and the Ducati at Laguna...
From the book MotoGp Tech showing the M1 I4 crank versus V4 crank...
Admitedly, I am not as well versed on the subject of V4's vs I4's as you are Larry.
But...
Arent those weights you "assigned" based on your assumptions? I find it hard to believe that any racing organization would allow a 16 pound weight disadvantage to exist without it being somehow addressed (lighter materials, lightening), especially on a critical moving part. I know WERA racers who have their crankshafts knifed to save on inertial losses. If a WERA privateer can do it I am sure the Yamaha MotoGP team has some tricks up their sleeve.
__________________
More fun than a clown car on fire!
'01 Duc 748/853
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Admitedly, I am not as well versed on the subject of V4's vs I4's as you are Larry.
But...
Arent those weights you "assigned" based on your assumptions? I find it hard to believe that any racing organization would allow a 16 pound weight disadvantage to exist without it being somehow addressed (lighter materials, lightening), especially on a critical moving part. I know WERA racers who have their crankshafts knifed to save on inertial losses. If a WERA privateer can do it I am sure the Yamaha MotoGP team has some tricks up their sleeve.
The weights are indeed "assigned" but they are based on the fact that you
have to so much metal to get the job done and still have a reserve of
reliability... especially in the escalating HP wars of 800cc MotoGp... so what
ever lighter materials or lightening of parts shall apply to both the I4 and V4
cranks equally in this comparison...
Given that then you may also note that not only does the I4 configuration
come with an inherent weight penalty but a bearing drag penalty as well...
the I4 has 5 bearing journals versus the V4's 3 bearing journals... and every
bearing journal subtracts critical HP from the smaller 800...
The trick up Yamaha's sleeve is to spin crankshaft backwards to cancel
some of that extra negative weight affecting Rossi... but I think Rossi is
getting wise and asking questions about not only the best tire but also
the best engine architect...
From the book MotoGp Tech showing the M1 I4 crank versus V4 crank...
I assigned equal weight to both 800cc cranks
1 = 1 pound
2 = 2 pounds
3 = 3 pounds
I4 adds up to 38 pounds
4 #1
5 #2
8 #3
V4 adds up to 22 pounds
4 #1
3 #2
4 #3
That's a 16 pound difference...
uh-oh....!
1. You show 8 large counterweights for the I-4, when most I-4 engines have 7 and a primary gear drive, these days.
2. A 180 degree I4 motor (even a "big-bang" version motor with 2 or more cylinders firing together) has perfect primary balance, and does not NEED large counterweights to offset primary imbalance. The counterweights can be (and are) made VERY slim and light in a race engine - basically only big enough for the strength to prevent the crank from twisting.
A V-4 motor is not inherently balanced at angles less than 90 degree crank phasing (IIRC, I admit I'm stretching a little from past readings on the matter! ), and especially not V-format motors with crank big-bang phasing - and thus often require balance shafts or multiple balance shafts to offset these imbalances (such as the new twin balance-shaft Aprilia V-4 65 degree superbike motor. )
Even a nice 90-degree V-twin motor like the Ducati, has some secondary imbalance due to the non-sinusoidal piston movement, relative to the circular counterbalance of the crank.
Your estimates of relative crank weight are fun and theoretically correct in the simplest of terms (i.e. absolute minimum crank weight is always desired), but I will submit that NONE of the motorcycle cranks in MotoGP -and especially not in street bikes - are made as light as their absolute minimum achievable weight permissible by their inherent design - simply because a motorcycle REQUIRES sufficient motor inertia to improve grip, reduce wheelspin, reduce required rider reaction time, reduce electronic stability control intervention, etc, etc.
If every racing motorcycle was "better" or "faster" with the lightest possible crank mass, then the V-format would have a decided advantage, and all motorcycle engines would rev up like F1 race car engines. They don't - because of the need to retain more control and reduce wheelspin, as they don't have the luxury of tremendous downforce that F1 cars have, that reduces wheelspin and improves grip.
3. Your estimates are based entirely on assumptions that are not necessarily valid for motorcycles, as mentioned above. I would submit (i.e. "guess", as NONE of us actually KNOW for sure), that the ACTUAL crank weight of the Yamaha and Kawasaki I-4 averages not much higher than the average of the V-4 motors, for the reasons described above.
4. Very nice of you to measure the fairings, Larry! Did you measure them at their WIDEST mid-section point (around their radiators), rather than below the rads as in the pic you supplied? And what exactly WERE your measurements at these points? Inquiring minds want to know.
5. PS. In discussions on friction, I notice that you continue to ignore the INCREASED friction of double the cam drives, double the cams, and heavier engine cylinders (combined) and heads (combined) of the V-format motors. This at LEAST partically offsets their crank advantage. I'd be real interested to know how much extra drag/friction is incurred by the doubled cam drives - whether that is extra sets of gears or tensioner-laden chains with all that extra friction.
Good discussion, as always, thanks!
__________________ Old Baldy / WWBO #451
Ducati 996
Kawasaki KLR 650 '02
Kawasaki KLR650 '06 OB's Blog
3. Your estimates are based entirely on assumptions that are not necessarily valid for motorcycles, as mentioned above. I would submit (i.e. "guess", as NONE of us actually KNOW for sure), that the ACTUAL crank weight of the Yamaha and Kawasaki I-4 averages not much higher than the average of the V-4 motors, for the reasons described above.
You're right... a 800c I4 crank weight more than a 800cc V4 crank...
Quote:
Originally Posted by Old Baldy
4. Very nice of you to measure the fairings, Larry! Did you measure them at their WIDEST mid-section point (around their radiators), rather than below the rads as in the pic you supplied? And what exactly WERE your measurements at these points? Inquiring minds want to know.
I measured them at all points... M1 is 2 inch wider than Ducati... and here's
an interesting find... the frame rails on Rossi's M1 is 1 inch wider at the
swing arm pivot than Yamaha's production R1...
Well the Kawasaki Inline 4 doesn't seem to be doing too bad, does it?
As for Mamola's quote that Stoner wouldn't have won a race on the Repsol Honda, as Pedrosa won a race, why does he not think Stoner would have? Does he think Pedrosa is faster than Stoner if they were on equal machinery?
Refer to Pedrosa v Stoner 2005 and Pedrosa v Stoner 2006 for two season's worth of data to support that conclusion.
More evidence can be found by looking at the 2 full seasons that each did on 125's.
Stoner had 2 wins and a best of 5th in the Championship.
Pedrosa had 8 wins and won a championship.
Mamola is looking at 2 years of 125 racing with equipment that is very equal in the top half of the field. He's also looking at 1 year of 250 racing head to head where each had top machinery and equal tires, as well as 1 year of MotoGP racing where each was a rookie on a Honda 990 and Michelins. In all those scenarios Dani performed better.
Quote:
Originally Posted by kiwigav
As for Mamola's quote that Stoner wouldn't have won a race on the Repsol Honda, as Pedrosa won a race, why does he not think Stoner would have? Does he think Pedrosa is faster than Stoner if they were on equal machinery?
Well the Kawasaki Inline 4 doesn't seem to be doing too bad, does it?
Kawasaki went MotoGp racing mainly to boost Kawasaki Heavy Industries, Ltd. corporate image on the world stage... they had been absent for Gp
racing for over 20 years but had gained valuable experience in the WSB
wars and so their first MotoGp bike was understandably a SUPER
Superbike... that didn't work... frame was too stiff and the classic 180º I4
screamer lacked traction in corners... Kawasaki then adopted Honda's lead
in control flex frames and copied Yamaha's lead in irregular firing order or Big
Bang I4 and the team has moved forward ever since... so it looks like their
current 800 I4 design are not doing too bad and Hooper may get the best
results out of it in 08...
Kawasaki actually ran the KR500 500cc square 4 GP bike through 1982, so they were only away for about 20 years.
Don't know if the first ZXRR had traction problems, but it was definitely primitive and slow.
Quote:
Originally Posted by Busy Little Shop
Kawasaki went MotoGp racing mainly to boost Kawasaki Heavy Industries, Ltd. corporate image on the world stage... they had been absent for Gp
racing for over 40 years but had gained valuable experience in the WSB
wars and so their first MotoGp bike was understandably a SUPER
Superbike... that didn't work... frame was too stiff and the classic 180º I4
screamer lacked traction in corners... Kawasaki then adopted Honda's lead
in control flex frames and copied Yamaha's lead in irregular firing order or Big Bang I4 and the team has moved forward ever since... so it looks like their
current 800 I4 design are not doing too bad and Hooper may get the best
results out of it in 08...
), and especially not V-format motors with crank big-bang phasing - and thus often require balance shafts or multiple balance shafts to offset these imbalances (such as the new twin balance-shaft Aprilia V-4 65 degree superbike motor. 
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