Hotfoot
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Posts posted by Hotfoot
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I attended CSS LVL 1-2 during the weekend of September 15 & 16 and I am trying to figure out what tire pressure was set when I brought my bike through tech...I was on a white Ducati 848. Tires used were Pirelli Diablo Rosso Corsa...<br style="color: rgb(28, 40, 55); font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">Thanks Fred
I remember your bike. I think we set you at 31 front 30 rear, cold. As I recall recommended track pressures for those tires are something like 31-34 front and 28-32 rear.
How did you like those pressures? I haven't ridden on those but I've heard they have a softish sidewall and some folks run them on the higher side of the recommended pressures to get more feedback.
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Did you have the oil changed recently? Some additives in (car!)-oils that are supposed to reduce friction are poison for motorcycle clutches.
Yes, it gets changed often because I am racing it, it was changed right before my race. It was done by a motorcycle mechanic, hopefully using the right oil, but I can check. What should I look for as a bad oil or additive for a race bike? This bike has a CR250X dirt bike engine.
Thanks for the tip about the oil as something to watch for.
I'll be changing the clutch anyway due to a high number of hard hours I've put on it, it's almost certainly due for it.
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You got it right about the slip occuring at the torque peak in a high gear, next it will just start slipping at high revs. I wouldn't bother measuring or inspecting givin the amount of time you have on it alone! I would replace all the friction and pressure plates along with the springs. There will be some bigger pressure plates and you may need a few of those so you can set the pack hight with all the new parts. When you have it apart make sure the friction plate ears haven't beat grooves into the clutch hub teeth, that can cause the clutch to act funny.
Yeah, I was thinking about that - I do have quite a few hours (and a number of race starts) on that clutch now, and don't know how many it had on it before I got it.
Ok, thanks for the advice, I'll get it done before the next races.
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There is only two things that can cause rpm to jump rapidly; slipping or extra acceleration. If acceleration is constant, then something must give. AFAIK, it cannot be something in the gearbox, because it would jump, not just let the rpm down. Nor can it be the final drive chain because it's the same thing. So we're left with the clutch or the tyre. However, the tyre would be most likely to slip in the lower gears and the clutch in the higher gears. If engine torque is at its peak around 11k, it may be the clutch being just a bit too weak to withstand it in 4th gear and higher. If you do not notice it in 5th and 6th, it could be that due to the spacing being tighter that you do not let the rpm getting that low under acceleration in those gears.
I should clarify that it is a 5 speed bike, and 5th gear is a weak gear that doesn't pull as strongly as 4th - I don't use 5th much and don't shift into it until over 12K. So your answer makes a lot of sense, it is certainly possible that around 11K is the peak torque and the hardest work the clutch ever has to do is in 4th gear at that RPM.
So... currently the bike pulls strongly and my starts are good, so the problem may not be immediately obvious to a mechanic - is there a way to check the clutch to see if it is getting worn or weak, to try to confirm it as the source of the problem?
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Hi there, I've got a question about my Moriwaki, which has a stock Honda CR250X motor in it. Recently I've noticed that just under 11,000 RPM, when I am accelerating, the engine sounds like it revs up suddenly and I see the tach jump up a few hunderd rpms, then continue its normal smooth increase. It ONLY does it right below 11,000 rpm. (Redline is around 14,000.)
At first I though maybe I was spinning up the rear wheel but it happens even with the bike straight up and always at the same rpm so I don't think that's the problem. I've only noticed it (so far) in 4th gear, not sure if it does it in other gears.
What could be causing this? Could the clutch be slipping, or some other transmission issue?
The power feels consistent through the sudden rev - there might be a very slight hesitation but definitely not a surge in power - it is just the sound and the tach movement that is catching my attention and making me wonder if there is a problem brewing.
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As I recall there is a VERY BIG difference between the "street" Power Pure and the track version sold by track vendors. The round profile is a more street oriented tire that is a lot less sticky on track. It's weird that they call both versions the PowerPure, quite confusing.
Yeah, they should at least call the track version of it the Power Purer or something to make things less confusing.
Amen, or how about Mo' Power. Or RACE Power. Or Pure Race. Or Pure Race Power. Or... Jeez, this is easy, I can't believe they couldn't come up with other ideas!
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I recently took my very first trackday/clinic - woohoo! Super stoked about it, especially considering it was raining cats & dogs all day, yet I was riding faster & more confident than ever before!
Now, towards end of the day I realized I have a problem with braking. Sometimes I would approach the turn entry point a fast enough to require some hard braking, and once I managed to lock it up. It felt like bike was sliding, but was not unstable - ie it kept going forward with no noticeable wobble. I released front brake pressure a bit and it stabilized itself (obviously I was not using rear brake at all).
Coach was riding behind me, and didnt notice anything wrong, and wasnt able to offer any explanations. I think my problem is not fully releasing the throttle while braking & downshifting. This sometimes happens to me whenever I start to push the envelope a bit - not exactly fear but just insufficient attention towards full throttle rolloff. Obviously I need to work on my brake/down technique.
I am trying to understand what happened... could it be that my front tire was not locked, but rear was spinning & loose due to the throttle not being completely off? I was in 3rd gear for pretty much all turns, Kawi Ninja 650 (all stock).
Thanks!
Peter
I was chatting with Will recently and he mentioned something that you might want to check on - he said that sometimes a rider's glove can be a bit too loose in the palm, making it hard to fully release the throttle while braking. Apparently it can feel to the rider as though he has released the throttle but the material in the palm of the glove (which is usually a high-grip material) keeps the throttle from going closed. I'm not sure if the happens because it creates a fold in the leather or just because it is loose, but when I read your post I thought it might be worth mentioning, something to watch for. I have had it happen to me and I didn't know why; after talking to Will I think a too-big glove was the actual cause.
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California Highway Patrol says: "Lane splitting is permissible but must be done in a safe and prudent manner."
That means that it is the officer's discretion - if he/she thinks you are going too fast for conditions or riding unsafely, you can get a ticket, but being in between lanes is not, in itself, disallowed.
Lane splitting here in LA is very, very common - on a typical rush hour commute, if traffic slows or stops, lots of motorcycles will come by in between lanes, and of course the CHPs do it all the time, too.
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As I recall there is a VERY BIG difference between the "street" Power Pure and the track version sold by track vendors. The round profile is a more street oriented tire that is a lot less sticky on track. It's weird that they call both versions the PowerPure, quite confusing.
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How does one get good at anything?
We get some form of this question often, "How can I get ___________ good?" Whatever the blank is: drag a knee, use a lot of lean angle, ride as fast as one's friend, a coach at the school, etc.
Is it all natural talent, big cajones, mental toughness, education, seat time, the latest bike and tires, cool suspension bits, good advice from friends?
What about other sports/activities, what format of training works there too?
As is obvious to anyone who has been at the Superbike School, we think correct information is a good place to start. Go over the theory, get a solid understanding of it, and there is a priority of information. The information that is most critical is presented first.
In the absence of a school, one could read the material available on the subject. A thorough review of the books and material available would be the next option.
This is first in a series I have in mind, but want to see if the subject piques your interest or not.
Let me know what you guys think on this please.
Best,
Cobie
Well, let's see... I wanted to get good at riding a motorcycle.
Natural talent? No.
Started at a young age? Nope.
Big cojones? Definitely not!
So I guess in my case the answer would have to be good training!!
Thank you CSS, who ever imagined I'd end up racing motorcycles?!?
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I asked the same question the guys from Continental at the June CSS at Silverstone. They replied the most important reason for not running the tyre in the opposite direction is hidden in how the tyre is actually constructed.
Simply put the core of the tyre is made out of a long strip of "rubber". In order to make this strip a circle you have to connect its ends by overlapping them so that one is over the other. The correct direction of rotation of the tyre is such that while rotating it doesn't "hit" the edge of the overlap to eventually cause a critical damage.
That was enough for me to stop flipping tyres
Regards,
Tony
Agreed on this, that is the same thing Will told me. There are different ways to connect the ends, and only certain methods are compatible with being able to flip the tire; for instance if the overlap at the end was cut to a 45 degree angle, you wouldn't want to run it in the direction that could peel back the end of the junction.
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Oh wow I didn't know the GP bikes had that kind of technology! Does anyone have a picture of this body position? It kinda makes sense but of course visual is always better, the video didn't show a whole lot.
Photo 4 in the slideshow on the superbikeschool home page looks like a hook turn in action.
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We've had a few discussions here on the forum about what you do to physically prepare for a trackday or racing - what sort of exercises and fitness routine, and even what to eat that day - but what do you do AFTER a day of riding or racing?
Do you have a routine for the evening after a hard day of riding, or the next day? Do you eat or drink anything in particular (I suspect a cold beer might be a popular choice!
), or take any sort of recovery vitamins or electrolytes? Is there anything you do to prevent sore muscles? -
Mine has a plastic outer shell but the impact absorbing material is a honeycomb metal of some sort. I don't think it would break down like foam, and the proctector itself looks perfect (straps, etc.). My leathers are fitted based on the shape of it, so I think I'll keep it for now - until I learn of a reason to change it!
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I'm very pleased with my Forcefield protector, have used it at every school for a few years...impressively comfortable too.
Have you ever seen any data on how long they last, if they ever need to be replaced? (Aside from if you fall down, I'm just talking about age or amount of use.)
I have a Dianese, I've been using it long enough that I am starting to wonder if it's time for a new one.
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Coaching humor! I like that. I can guess how that debrief would go..."How did 'The quick brown fox' drill feel? What areas on keyboard do you feel went well?"
Repeat after me: "One the quote box is turned on, its used evenly and smoothly throughout the remainder of the thread"
Ha ha...
How about this:Do you ever feel a bit rushed when you are trying to reply to a forum post? If you were to give yourself a bit more TIME to get it posted, so you weren't having to hurry through the control actions, would that make it easier for you to find the right buttons?
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I think looking at chicken strips as a gauge of how much grip you have is a bad idea and will probably end in tears! In all my time riding/racing bikes, I have never worn a front tyre all the way to the edge. I just don't think the profile allows it.
I agree with this 100%, I've never worn a front tire to the edge either (on a big bike like a 600 or 1000). On the small bikes (RS125 size) I've done it, but on those low hp bikes the rear tires are much narrower; I think the much wider rear tire of the bigger bikes is why the front don't wear to the edge.
Yes you can "push" the tire even without having the bike leaned way over, and the most common reason (aside from braking too hard while leaned over) is being stiff on the bars, which overloads the front tire and does not allow the handlebars to move to compensate for irregularities in the road.
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QUESTION: Going around a roundabout at medium lean, just as I started to open the throttle, the bike added quite a bit of lean. Like it would if the tyres let go. Only I don't think they did. What input could I have given to cause that?
Going to quote directly from Twist II here:
"If your throttle control is standard, the only things that will change the lean angle of the bike to any great degree are a slide/catch action or steering input."
This is from Chapter 13 and it is well worth reading the entire section.
Is there any chance that you pull on the bar slightly when you roll on the throttle? Are you hanging off a lot, and if so, when you hang off all the way AND try to roll on the throttle, does it create an akward angle that can cause an unintentional steering input? (If you can, try putting your bike on a stand, hang off, and simulate rolling the throttle all the way on, and see how comfortable it is for you, some riders's wrist get bound up in right hand turns, and some have trouble reaching the throttle when hanging off on left hand turns, either of which can create an accidental steering input.)
Totally agree with you on "riding carefully". Have you abalyzed WHAT specifically changes in your riding when you "try to be careful", and what the effect are?
And yes, looking in the mirrors while riding is difficult! We do that some, as coaches, and it can take a while to get used to it. It is very easy to make a steering error while doing it. For example, looking too long in the left-side mirror while in a right hand turn can make you run wide (and vice-versa), presumably some form of "we go where we look!".
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I'm here. I am replying from my iPhone. Cobie... have you tried "readers"?
Actually I think the iPhone access is pretty decent - if you have good eyes - but editing a long post is tough.
The very best thing about the mobile app is that you can view new content - which shows only posts you haven't already read. Love that.
I did find one thing, Cobie, that could have happened to your reply. When you are done typing, you hit "Done" on your keyboard to make it go away, then you ALSO have to hit the "Add reply" button below the edit box to actually get it to post up.
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I tried watching the video but can't see anything well enough to have any thoughts about what is happening - I assume you are the rider in front, not the rider actually carrying the camera, and if so, on my screen the size/graininess of the image and the shadow make it really hard to see anything.
My thought about the dual compound tires came from your comment that you could lean the bike over a lot and get good grip, but at shallower lean angles suddenly slide - since you would be riding on the harder compound at shallow angles you might really GET less grip and thus get surprised by a slide.
But, there are a lot of other things it could be! First, some basic stuff - what tire pressures do you run? Have you set your suspension up? Are you tires and suspension in good condition? Did you notice anything about the surface of the road?
Do you ever use your rear brake in turns?
Take a specific (and typical) example of an unexpected slide - where in the turn did it occur, at the entry, the apex or the exit? What other details do you remember, were you entering faster or slower than normal, turning in a different place, driving harder or less, were you using the brakes, and any details of what you felt the bike DO, exactly, right before and during the fall. Maybe with the collective wisdom of the group we can help you diagnose the cause of these unpleasant slides!
Of course the best solution of all would be to get thee to a school so you can have a coach watch you all day long, that would probably get it solved in no time flat.
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Are you, by any chance, riding on dual compound tires now, that have a different compound at the edges versus in the middle? Lots of tires are that way now, and it could make sense that you are feeling the grip change at different lean angles, which would not have been a factor years ago.
Also, on one particular dual compound tire that I used to use, there was a very soft aggressive compound at the edges, that was super grippy, but wore out quickly and got very slick once they were worn out. On those when I leaned the bike over and transitioned from the harder compound to the softer once, the tire would abruptly begin sliding. The tires were great until they wore out but I didn't like the unpredictability once they did start to go off, so I stopped using them.
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Welcome! Thanks for joining us, lots of nice people here and great info to be had, post up your questions. Glad to hear you are an enthusiast and we look forward to seeing you at a school!
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Hey Craig,
Those are good points - thanks! I was thinking that the foam seat would probably have a little more resistance when transitioning from side to side, possibly making it more difficult. Although my last time out at CSS, I was working on LESS butt movement, MORE upper body movement
.If there is more friction with the foam seat, it would help during braking for sure, as I tend to slide forward even with a pretty good lock on the tank with both legs.
Maybe foam is the way to go...
Foam might be lighter, if you are trying to reduce weight, and you can buy foam that is thicker or thinner, or shape it however you want, and you can shop for foam that is more, or less, grippy. But I think the main consideration is the tail piece itself and how you want it to look. I think with some race fairings the "race tail" that used the foam seat was more suitable for putting on race numbers, and may also have been easier to put on and take off.
On my bike I bought a thicker foam seat and sanded it down in the middle so it was a little higher at the front, in an attempt to keep me from sliding forward so much. That helped a little, but not as much as I had hoped. Someone also told me that if you rough up the foam occasionally with sandpaper it helps keep it more grippy, that with wear it gets a little polished and more slippery.
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For those who may be interested, here is a nice article on basics of how front forks work - it talks about progressive springs and different types of damping (high/low speed, shim stacks, etc.):
http://www.motorcyclecruiser.com/tech/fork_suspension_technology/index.html
And a very interesting read from some people who were toying around with suspension on a cruiser, with some data collection. It's a lot different from a sport bike but does cover some cool info:
http://www.motorcyclecruiser.com/tech/improve_ride_suspension_performance/index.html
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What About After You Ride?
in Cornering and Techniques
Posted
I'm surprised not to see more feedback on this topic. No one has any special lotions, potions, or secrets to prevent sore muscles or refuel after hard exercise, or exertion on really hot days? No special supplements or vitamins, jacuzzi soaks, or Advil?
I sometimes use a hot bath or Jacuzzi soak to prevent sore muscles. That seems to work well, when I have the time/opportunity to do it. However, my biggest challenge is getting properly rehydrated after really hot days at dry-climate tracks; it seems like I stay thirsty (and cotton-mouthed) for a couple of days, no matter how much I drink (water or Gatorade). I've started taking some potassium at the end of the day, to see if that helps - so far it seems like it does.
For my horses I feed an electrolyte supplement that can be given before and after exercise, it's a powder. Anyone done anything similar for yourself, with good results?
This doesn't just have to be about riding, whether you climb mountains or run marathons or work in construction, if you have ideas that work, I'd like to hear them!