[rsheidler]

Re: More than one reason for doing this

I am sure you are right that the twin shocks DIRECTLY do not have any effect on frame flex. My guess is that it is a matter of where the shock loads feed into the frame.

I used to keep all my Cycle World (and other) magazines, but my wife finally cracked down -- in exchange for her "allowing" me to subscribe to 3 motorcycle and 3 car magazines, I have to "agree" to throw out the old issue when the new one arrives. If anyone has anything by Kevin on this, I would be really interested in seeing it.

Regards

Bob

 

[rsheidler]

I had considered that, and had also read other comments to that effect. However, it seems like far too substantial a member to be simply a measurement device (although there is some sensor attached to the strut on the left side in one of the photos). You will note in the photos that the sensors for measuring rear suspension travel are much smaller.



Also, the comments in the Yamaha site indicate that they are dampers:



"Featuring two main damping units across the top of the main chassis this concept explores the flex characteristics of the alloy frame and is targeted at improving rider feel."



Of course, the factory would never release information that would mislead us (or their competitors) now, would they?



Regards

Bob

 

[rsheidler]

I believe you are absolutely right, and I had considered including some sites related to the Ducati's "controlled flex" and the new double sided swingarm, but decided that would be too much for this article.



Changing the subject slightly -- I am going to stick my neck waaaay out and predict that Ducati take both rounds of today's WSB at Valencia!



Cheers

Bob

 

[rsheidler]

I'm not "really" making fun of Dirck (well, maybe just a bit, but in a good natured way). I read his site pretty much every day, and I thought his feature on the M1 prototype was good enough that I chose to link to it.



The snow is mostly cleared today, and I am almost tempted to fire up the Ducati and take an (illegal) shakedown run around the backroads, but there is a very muddy 1/4 mile of dirt driveway, and the Duc is still wearing slicks. Guess I better stay home and watch the WSB races on the tube instead.



Cheers

Bob

 

[rsheidler]

Re: What they didn't mention

They *are* copying another traditional Harley feature -- longer wheelbases. Kevin Cameron first reported that he had surrepitously measured the RCV wheelbase and found that it was at least 3" longer than what had been used previously. Experts believe that all the new, specific to 4-stroke, chassis are using longer wheelbases. For such powerful, light bikes, acceleration is wheelie limited rather than traction limited, so the only way to get more acceleration out of a corner is to stretch the wheelbase.

Cheers

Bob

 

[rsheidler]

World Ducati Cup

I was pretty impressed with the Corona Suzuki today. Raced much better than they qualified. Given a bit more development, they could at least get this thing on the podium.

The Petronas also was pretty impressive. If they get the hoped-for new motor with more power, they could be pretty competitive by the next round at Phillip Island.

Cheers

Bob

 

[rsheidler]

Other Valencia Results

Click on SuperStock Results for World SuperStock results from Valencia today.

"Production" 1000cc -- Ducati 999 beats Gixxer 1000 and R1. Not exactly sure what mods are allowed -- I think it is just shocks and exhaust, similar to AMA Supersport.

SuperSport Results for World SuperSport.

Looks like the "old" gixxer 600 is not yet obsolete -- Suzuki, Honda, Yamaha 123, best Kwacker was 11th. Be interesting how this compares to Daytona next weekend.

Unfortunately, SpeedTV doesn't show these races here. Could be better races than the Superbikes.

Bring on the racing!

Bob

 

[rsheidler]

Great Marketing Idea!

We can introduce a "Rossi Replica" line of arm chaps, in his trademarked neon yellow, and a "Rossi Replica" beanie helmet to sell to the guys riding Honda cruisers.

They can identify with the 1%ers and the racers at the same time.

Good luck with the b'day party. I have also missed lots of riding opportunities to spend time with my daughtor, and with the benefit of hindsite, I don't regret a second of it.

Cheers

Bob

 

[rsheidler]

Chain Alignment

Hmmmm.....I recently read on Colin Edwards' web site that his Aprilia had at least one broken chain in the recent IRTA tests. If true, it could be a result of misalignment due to the swingarm flex.

Bob

 

[rsheidler]

Re: What they didn't mention

For clarification of what I am saying, please click here and here

Cheers

Bob

 

[rsheidler]

Re: Great Marketing Idea!

That is not necessarily pre-destined. My daughter is 17, and very independent, but given a choice of skiing or mountainbiking with her friends or with her old man, she will almost always choose the old man -- often asking her friends to join us. We spent this morning sitting in front of the TV watching the World Superbike races (aka Ducati Cup).

She also holds my hand and calls me Daddy and kisses me good-by in front of her friends. Of course, she is working on me to buy her a 620 Monster so she may have some ulterior motives ;-)

Cheers

Bob

 

[rsheidler]

Racing Pushrods

Twin-cylinder, air (actually air-oil) cooled pushrod twins expected to win at Daytona next weekend check this out -- watch it on SpeedTV!

 

[rsheidler]

Re: What they didn't mention

Man, you shot your dog? What kind of a man are you? How could you? I'm gonna call the SPCA!

Seriously, did you actually read the article, or just the opening paragraph? I opened the article by posing the tongue-in-cheek question of whether this was copying Harley or cutting edge technology, then spent the entire remainder of the article attempting to explore that cutting edge of motorcycle racing technology -- a subject very near to my heart.

It never occured to me that anyone would seriously think that a GP bike would "copy" Harley, so that reference seemed sufficiently subtle. Perhaps in the future, I should include a warning on my posts -- you know, like "Parental Advisory, may contain adult language, violent imagery and ironic content."

For the record, I have owned 6 Yamahas, and no Harleys -- in fact, the last time I rode on one was as a passenger in 1961. I also have nothing against Harleys, and am half-way interested in a Dyna Sport as my next street bike.

Just a friendly advisory -- if Buzglide or Longride (or someone responding to them) make any reference to their dung-heap Harleys flinging parts and spewing oil, it also is tongue-in-cheek.

Cheers

Bob

 

[rsheidler]

I won't recheck your calculations,but they intuitively seem about right. However, I would clarify that the lean angles you cite refer to the angle between the center of the contact patch and the center of gravity of the bike/rider unit. With very wide tires, the contact patch moves well to the inside as the bike leans, requiring the bike itself to lean further, partially offset by the amount by which the rider leans off.



If you examine pictures of GP bikes, or even AMA Superbikes, the apparent lean angle of the bike looks to be well past 45 degrees.



Even if the maximum vertical component relative to the track is as high as 50%, this is still a significant problem. Assuming that the bike encounters a vertical bump of 1". If the suspension fully absorbs that bump, there will also be a horizonal suspension deflection of 1" so either the bike or the tire's contact patch deviates from its intended course. Given the realtive inertia of the bike and rider, it is likely that the tire does most of the deviation. In either case, traction is seriously compromised.



It is always a pleasure discussing technical issues with you, and I always come away with a better understanding of the subject as a result.



Best Regards

Bob

 

[rsheidler]

What? No Panhead?

They stopped making the panhead? Why wasn't I informed?

Bob

 

[rsheidler]

So Ducati is dealing with totally different issues than, say, Honda in developing their GP bikes? Certainly, the specific ways they design and construct their frames to achieve the desired flex will be different, but the objectives are exactly the same. Laws of physics don't give a $hit about frame material.



Not sure (maybe some Harley historians here can confirm or deny) but I believe that Harley had the first disk brakes on a production bike -- before the CB750, and sportscars had em before Harley, and airplanes had em first. You are right, who cares?



In case you missed it, this reference is a good-natured dig at some of the Harley guys who are always accusing the Japanese of copying Harley, as well as some of the sportsbike guys who are always putting down Harley (as well as anything other than a race replica sportsbike) for supposedly employing obsolete technology.

 

[rsheidler]

Re: What they didn't mention

>>One day i will weld up my own (sporting) frame with a big ole Merch in it with some dirt track high level pipes, the whole thing will be polished stainless and aluminum. Top spec brakes and suspension. imagine a homebuilt confederate, with ground clearance. And for 30 grand less. <<

Bring it on!!

My own fantasy Harley would be a Dyna Sport with 17" (or "18, if it looks better) wire spoke wheels (I am a Luddite at heart) with sport-touring rubber, longer high-end shocks (Ohlins, if they have anthing that will work) to get more clearance and quicker steering, moderate rearsets (still leaving room for passenger pegs) and moderately lower bars, upgraded brakes, a moderatly breathed-on engine and a Corbin seat. Basically, a naked, 2-up sport-touring rig that is a little different from the typical BMW roadster, etc.

Cheers

Bob

 

[rsheidler]

The 35mm forks on my SR500 certainly have no difficulty deflecting sideways enough to absorb any bumps encountered while leaned over -- of course they also bend around every other direction as well -- fore and aft (you can actually see it bend back under hard braking) and torsionally (counter-steer hard and the wheel catches up a fraction of a second later). The USW forks on my Ducati are a lot stiffer and those on superbikes and GP bikes are much stiffer yet. My guess is that Honda started the flexible steering head thing for just this reason.



Actually, it seems that maybe fork tubes should be oval instead of round, so they could be very rigid fore/aft and more flexible laterally.

 

[rsheidler]

Yeah, manufacturing would be a bit tricky -- can't just chuck a chunk of steel in the lathe!

 

[rsheidler]

Nope. Pushrods

This from an article by Steve Anderson -- For more info CLICK HERE

"The valve gear is as simple as it can be for a four-valve boxer: A single camshaft mounted high in each head opens each pair of valves via a very short pushrod and a single rocker arm with an extension for each valve. Valve lash can easily be set through screw adjusters. The camshafts are chain driven from a jackshaft under the crank; the jackshaft also carries the oil pump."

OHC would likely have made the engine wider, compromising cornering clearance. Also would make valve adjustments more difficult. My best friend's wife does her own valve adjustments on her R1150C.

Bob