Jump to content

racer

Banned
  • Posts

    1,135
  • Joined

  • Last visited

Posts posted by racer

  1. I believe the topic was training/cornering machine. The second post narrows it to v2 vs i4.

     

    The answer to that query is v2 because it is typically lighter, so will corner faster. And, as a training machine, it has more tractable power in a larger band allowing one to focus more on riding with less focus on shifting or high-siding. Another benefit is less maintenance cost for half the cylinders.

     

    That said, I've never owned one and the idea of buying an EX500 over an FZR400 for a first track/race bike was laughable to my mind back in 1989.

     

    But that's me. I wanted to win. Go figure. :)

  2. Sure, Cobie.

     

    First, FYI, after clicking on Reply or "Reply, etc, to post a comment in a thread, the BBCode Help button will appear in the bottom right corner of the comment text field. This will access a help page for most of the BBCode that works with this forum software package.

     

    The code for posting photos is: img ] gives us Gorlok

     

     

    http://i443.photobucket.com/albums/qq152/gorlok/buttonwillow/rsw1.jpg' alt='rsw1.jpg'>

     

     

    Cool helmet, dude!

     

    Cheers,

     

    racer

  3. Interesting topic. Very nicely explained Racer.

    Thanks.

     

    I remember reading some time ago that riders were unwinding the preload on the rear spring to attempt to get a "softer" ride.

    Now this combined with rising rate linkages in fact made the suspension "harder" because the swingarm was now in the region where a lot more force was required to compress the spring.

    In other words, more preload can = softer ride (softer meaning compliant).

    Interesting. Very interesting.

     

    I hadn't considered the relationship of rr-linkage orientation to pre-load.

     

    Thank you for that insight, Big Willy.

     

    racer

  4. Do you work for kneedraggers or just posting reviews from their site? They're based in DE, right? You live on the east coast?

     

    I work for a motorcycle dealership that sells tires from Tucker-Rocky and Parts Unlimited. I don't know anything about kneedraggers.com. I just Googled the tires for some feedback.

     

    I am located in PA.

  5. Just put a set of Corsa III's on this past Monday. Morning track temps were in the 40's and didn't want to push my Pirelli diablo's. I was quite impressed. Sticky as hell. I'll see how long they last.

     

    I've gotten good feedback on the Corsa III's from my customers.

     

    Dual compound. Similar to the Dunlop Qualifiers. The center tread compound should help them last longer on the street than if they were sticky all round.

     

    Here is some feedback on the qualifiers: http://www.kneedraggers.com/details/Dunlop...es--509023.html

     

     

    And the Corsa IIIs: http://www.kneedraggers.com/search/search....sa&search=1

  6. Hey Jay,

     

    OK, I think I see where you were going before vis a vis, parasitic forces. Yes, it is mostly friction due to gravity that causes deceleration when you close the throttle. And, why the forks compress. But, the weight distribution also allows you to apply more turning force.

     

    Yes, there is a theoretical point of diminishing returns if you apply too much weight or turning force, but, the traction of modern racing tires is pretty much beyond that unless you are trailbraking or the track is slippery. I have never flicked a bike away with too much weight on the front end except in slippery conditions or with cold tires.

     

    Bottom line is that you can not turn in as hard or fast if you are on the gas, even at low speeds, because there won't be enough weight on the front end. And the geometry won't be as tight. You will run wider than if the forks were compressed.

     

    That said, according to Cobie/Keith, turning up your idle, which is essentially the same thing as having the gas on a very little bit, can be helpful. But, I think that has more to do with the transition from off throttle to on throttle than maintaining speed during turn in. I don't have a copy of Soft Science so I don't know what Keith has said about it. But, I think it would be very difficult to consistently accomplish that trick by hand in any case. And the issue of having enough weight on the front end to turn hard and fast and sharp remains.

     

     

    PS - I switched to two strokes GP bikes before I ever heard of raising your idle speed. GP bikes have no idle circuit, eg. they don't idle. So, I guess there is a scenario in this milieu I am not familiar with.

     

    racer

  7. When I watch racing on TV, I like seeing the telemmetry data onscreen almost as much as hearing the engines as the riders go through the corner. Seems to me that they're keeping some gas on.

     

    As has been said, there are undoubtedly some corners where they are. But, the basic formula for a "sharp" corner that requires significant velocity change to negotiate does not.

     

    May I humbly ask dear Sirs, is the technique the same for a rider on a 2008 CBR1000RR versus a 2003 SV650? How about an RS125? On the superbike you want to get it turned, pointed, stood up and on the gas, right? 125: Cornerspeed. Where do they differ?

     

    A superbike or motoGP or even a 600 have more power to put down, hence, benefit from getting the turning done quickly and lift up to utilize that power to overcome the corner speed deficiency due to a longer wheel base and more mass.

     

    A 125 is shorter and lighter, hence, in the hands of a skilled rider, can corner faster outright. Also, it does not have as much power to put down and must rely on maintaining corner speed to get a good drive out.

     

    Why does a rider like Sofuouglu do well on a supersport machine and not so on a superbike? Why does someone like Jonny Rea do well on both? (I hope that we're still on topic)

     

    Different strokes for different folks. Some riders can naturally adapt. Some riders have better technicians to adapt a bike to their style. Some don't.

  8. I stated earlier that I made a major change to my cornering technique in search of better results. And so, yes I've tried both ways. My best results have been going in with some gas on, quickly get to max lean and rolling on the throttle through the apex and then getting to WOT as I pass apex and get to the exit with my eyes on the next entry point.

     

    How do you define "best results"? How do you know? What was the circumstance? Were you keeping lap times?

     

    We've already been over the different types of corners and which ones you would want to be on the gas for. Please understand that I am speaking from the goal of racing, or the fastest and most stable and controlled technique when riding at the edge through corners that you must slow down for and turn sharply into.

     

    It's pretty obvious that being off the gas increases steering angle, but that's due to parasitic forces, not just "being off the gas", true?

     

    I'm not sure which parasitic forces you are speaking of, but, in any case, my reply is no. It is not just "due to parasitic forces". The dynamic state of deceleration alters weight distribution.

     

    Compare ideal vehicle to real-world and I think you'll agree.

     

    I'm not certain what you are asking me to agree with. But, what difference does it really make if I agree or not? Please understand, I don't need to scrutinize "beliefs" or "theories". I've already done all the "experiments" and am intimately familiar with all the scenarios in the "real world". I have thousands of racing miles, decades of data and mountains of scientific evidence to rely on. But I do wish you all the success on your own journey.

     

    Cheers.

  9. PS - We've done the experiments you suggested, ie. trying the turn both on and off gas at turn in... for several decades now. Really. We aren't just guessing or playing what if games. We know the answer.

    Now this is something more along the lines of what I was looking for.

     

    Truthfully, I agree with Mr. Code's work, but I believe that anything held as truth should be able to withstand scrutiny.

    Absolutely. Couldn't agree more. I'm suggesting you DO the experiments YOU yourself suggested. I wouldn't ask you to take my word for it at all. Of course, I suppose that is going to be a little difficult without a closed course race track, a video camera and a stop watch. Or a grid full of other bikes to race against so it becomes plainly obvious when and where other bikes are passing you.

     

    Can we consider this for a moment:

     

    What are the forces that predict the turning arc of a motorcycle?

    If we use a given speed and lean angle and use the same turn-in speed, why would the same rider not have the same arc through a turn?

    What other variables are there in a turning arc?

    OK, I think the point you are looking for is that, all other things being equal (tire profile, wheel diameter, rider inputs, etc), the steering head angle, and front geometry in general, determines how much the front wheel is turned in at lean, hence, the arc the bike travels at lean. This geometry also determines the degree of stability or instability of the front end, hence, the potential speed of the flick or turn in process. This is why sportbikes have the geometry they do as opposed to looking like, say, a Harley.

     

    What is required in order to change the steering angle?

    I'm so glad you asked that question, Jay. Like Cobie said, being off the gas compresses the forks and decreases the steering head angle or makes the front end steeper. Basic geometry teaches us that the sum of the angles of a triangle remain consistent. If you shorten one side of the triangle, you increase one angle and decrease another. In this case, the angle between the steering head and vertical decreases, and the angle between the steering head and horizontal (ground) increases. Sometimes it helps to draw yourself a picture or diagram to see the relationships.

     

    Thanks guys for working this through with me.

     

    Glad to be of service, Jay.

     

    racer

  10. If you begin the turn in at....say 60mph off-throttle versus 60mph on throttle, why would it make any difference in the turning arc? After this turn is executed, who would be able to got the WOT sooner?

     

    Keith has some very good diagrams and explanations in Twist II about this exact point.

     

    Read up on the "hook turn" and the idea that the faster you get to full lean the less you need to lean for the rest of the turn.

     

    With the front compressed, the the steering angle is steeper, hence the turn in is sharper. Hence, your flick or hook will be tighter and, off gas, you travel less distance than on gas while turning in, hence, by definition, a tighter turn in and less lean angle needed and more speed potential for the rest of the turn at lean.

     

    Check it out.

     

    PS - We've done the experiments you suggested, ie. trying the turn both on and off gas at turn in... for several decades now. Really. We aren't just guessing or playing what if games. We know the answer.

     

    Just trying to help.

     

    r

  11. Yes, I downloaded all six episodes. Good stuff.

     

    That said, there is a reason it is called "underground". They operate in a legally gray area vis a vis copyright laws. I think it would be a good idea if the link wasn't openly posted here. Happy to provide it to those who ask. The more seeds/peers the better. But it is my only access to racing broadcasts and I don't want anything to happen to it.

     

    Thanks.

  12. I have an animation of a constant mesh sequential transmission around here somewhere that I will post so everyone can see how a motorcycle tranny works and why it is important to blip before or at least during your shift.

    You put it out there, now you MUST show.

     

    Actually, the link for the animation is here on this website already. I think I posted it last year during a discussion about transmissions with another instructor here. Unfortunately I am at work right now and cannot really spare the time to go digging for it.

  13. Alright. I was at the track yesterday, and asked a few of the more seasoned racers about blipping. One of them explained it to me in a way I can understand, and made it that much easier.

    He said that to "blip the throttle," you squeeze the clutch, downshift, and before letting the clutch out: blip. That's it.

    Well, the thing is, he got it just a little bit wrong. The blip should happen before the shift. Yes, you can force the shift and blip later to merely smooth out the clutch release... as long as you don't piss around too long and manage to catch the shift at the right point. You'll get away with it for the same reason you can downshift without using the clutch at all. However, if you wait too long before shifting you will bounce the gear right back out again and do nice damage to the shift dogs in the process. I'm pretty sure the zx6's all come with undercut dogs, and, you will chip and break them if you get lazy. Blip before or at least during the shift to help match the gear speeds in the tranny and release the clutch quickly. You and your bike will live longer.

     

    He said that I can clutch in, shift, coast however long I want, and before letting the clutch out, blip it, and thats it. It's not a matter of shift/blip real quick. Just blip before letting out the clutch. Easy enough.

    And how do you figure that'll affect your lap times?

     

    There is no reason to blip between shifts when doing more than one gear, because ultimately it's after the last gear that you are going into that you need to match the neutral transmission to the engaging engine.

    Actually, there is very good reason. If you get into the habit of doing in the order you post here, the first time you get in over your head or get flustered and get your timing off you will damage your bike.

     

    I have an animation of a constant mesh sequential transmission around here somewhere that I will post so everyone can see how a motorcycle tranny works and why it is important to blip before or at least during your shift.

     

    Cheers,

     

    r

  14. Fabricate a bracket to relocate your master cylinder.

    Thanks for your reply racer, but it would help a great deal if you'd put some meat on the bones.

     

    Most model specific rear set kits include a bracket for the rear master cylinder. If your kit didn't include one, and fabrication skills aren't your forte, I'd suggest returning your kit and finding a different kit that does. As it happens, I am a parts person at the local Honda/Kawasaki dealership. If you tell me your make/model, I can hook you up.

  15. So, for a typical cornere like Mid-Ohio T5, I'll be in sixth gear and bang about 3-4 downshifts in about 1 to 1.5 seconds. Lastly, I (and Valentino Rossi) downshift one gear at a time using the clutch and blipping for every gear. Check out Japan MotoGP at Motegi and you can see Val clutching multiple times for multiple downshifts

    .

    OK, I understand your downshifting one gear at a time with the clutch, but when you say you blip for each gear, I'm taking that to mean revving the engine a bit to match its speed to what is needed for the new gear. Are you completely done braking at this time? The part that I'm not getting is holding the brake lever with your right hand, and at the same time rolling the throttle on a little for each shift. Sounds like a lot of tricky right-hand work. Your right hand thumb and lower palm are wrapped around the throttle with your fingers on the lever- it seems awkward to rotate the throttle in this position. Am I understanding what you are saying correctly?

     

    Ahhh... you have hit the nail on the head, my friend. Learning to blip the throttle while maintaining even brake pressure is the whole enchilada as they say.

     

    The trick for me is to use one or two fingers on the brake lever and let those fingers slide back and forth over the lever while working the throttle with my thumb and last two fingers. It does take some practice, but, once you get the hang of it, it opens a lot of doors. Frankly, IMO, it is the number one skill needed for track riding. For learning purposes, I suggest getting your blip/shift skill sorted out first before adding the brake.

     

    There are a number of threads devoted to this skill here, but, I think Keith has a chapter in his corner. That is probably the best place to start.

  16. There is nothing wrong with bringing the idle up to 3 or 4k, it will have an effect (even at higher RPMs). This is covered in Soft Science.

     

    Right. The same effect as not having the throttle closed all the way because, well... it isn't.

     

    It will reduce engine braking and some of the "lash" effect that Jay spoke of and can help to smooth out the transition getting back on the throttle mid-turn I suppose. That said, although it may help to overcome a poorly carburetted or inferior injection system, wouldn't it have the potential to become a crutch and/or possibly prevent a student from developing more finely tuned throttle control skills?

     

    Where is the idle set on CSS school bikes?

     

     

    PS - I don't have a copy of Soft Science. :shamed:

×
×
  • Create New...