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New Rider ForumsJust joining the motorcyclist hobbie? Looking to get some information about a first bike? Or have some newbie questions. Are you new to the website?
ive riden my ninja 250 for almost 1000 miles. sometimes im bored, and i think too much. here is the result:
1. when I let my hands off the bars between 30-50mph, the front wheel will wobble from side to side, why is this? Does this happen on all bikes? How do you deal with this phenomenon while stunting, with no access to handle bars?
2. when I try to do a stoppie, first the front tire will slighty lock, leaving a tire mark. If I stop even harder, the front wheel will wobble (before I can ever get the back tire in the air) and I feel like the bike will just fold over. i imagine I could do a better job holding the tire straight with the handle bars, but is that the solution? Do all bikes do this?
3. how do you tell when you are approaching the limit of traction? Once while leaned over I ran over some gravel and suddenly the front end felt loose, like I was no longer connected to the ground. I think the front tire might have skidded a fraction of an inch, and that was what I was feeling. I basically did nothing and didn’t need to. Is that the feeling I need to watch for? I keep pushing the bike little by little and I’m sure that eventually ill find the limit. I just don’t want to surpass the limit at the same time. I need to learn what type of bike feedback I need to be interpreting.
4. while doing wheelies at a constant speed, I was under the impression that you go back and forth between throttle (when it is below the balance point) and rear brake (when it is past the balance point). How then, do people wheelie at constant speed with their foot nowhere near the rear brake? Are they relying on engine braking to bring it down? Or does a bike come down on its own from past the balance point if you cut throttle? Why would it do that?
5. if we are to assume that both front brake and rear brake can be operated from 0(none)-100(full): then while in a turn, if the maximum braking that the front tire can withstand is x, then is the maximum braking the rear tire can withstand also x? let us assume that it is not x, and that it is y. in another scenario, if the front brake is being utilized by x amount, is the maximum braking that the rear tire can withstand still y, or has it now changed due to some change in braking dynamic when both front and rear brake are being used?
6. I watched a video online which demonstrated body posture during a turn. It mentioned to move half a butt cheek off the seat, towards the inside of the corner. That seems pretty conservative to me, if it is possible to move even further to the inside, isn’t that even better? At what point does hanging way off the bike to the inside become more of a hindrance than a help? Im talking about on a racetrack, not on the street.
7. im an idiot. I wear hiking boots, jeans, t-shirt, and a motocross helmet when I ride. If I were to invest in one piece of protection, what should it be?
8. what safety gear is required to do a track day at a typical track?
9. if the speedo is off by 10%, and the fastest my ninja seems to go is 100, then is the top speed of my ninja only 90mph? is something wrong or slightly off if the bike only goes that fast?
10. when braking in a straight line, you have 4 options, front brake, rear brake, engine braking, wind restistance. But does engine braking affects the rear wheel in the same way that rear brake does? In which case, since the rear brake is more than sufficient to surpass the braking ability of the rear tire, is engine braking not a factor? Is it possibly advantageous to pull in the clutch, so that you will know the limits of rear brake, rather than be applying rear brake in addition to engine braking (which will vary in significance depending on rpm’s), and make it harder to judge how much rear brake can be applied?
sorry, that was more like 23 questions
Last edited by whatismouse : 08-24-2008 at 11:41 PM.
1. no clue.. never noticed mine doing that?
2. never tried on my 250...
3. I just kept getting lower and lower in turns.. and to me.. i could just feel when I was pushing it too far for the surface it was on... and then you realize to not turn so sharp/fast on public roads... since there is all kinds of stuff to take your ass out in a turn...
4. Obviously easing the throttle will bring it down... but after some practice most people dont really use the rear brake unless needed... modulating the throttle seems to do... (but i have no clue... never had the balls to do it myself... when ur a broke college kid.. risking my 3000 dollar bike doing something i didnt need to do.. didnt seem smart...)
5. Not supposed to brake in a turn! that will end up poorly for you my friend... brake before the turn... or straighten up and brake... you can lightly modulate the brakes (back brake mainly... front is risky) but you shouldn't need to in most situations..
6. Leaning off changes the weight displacement/centripital force of the bike in a turn.. different people lean off different amounts... I'd stick to wahtever is comfy and safe... you dont want to be leaning in a turn hanging off so far you can barely hold onto the bike... you will notice GP racers dont lean super far off.. this is because their tires and bikes can learn further than most... generally track day junkies will hang further off to supplement the fact the bike/tires cant lean any further safely...
7. buy some gear dude - road rash aint cool - any decent gear will do.. I have 2 alpinestars jackets (love their air textile... great jacket for hot days), a full teknic suit, a* and teknic gloves... I love my shark helmet.. but my scorpion exo700 is almost as good and a lot cheaper.. Revzilla.com has some great sales.. as does motorcyclecloseouts.com
8. Full leathers 1pc or 2pc, Full gloves that cover the wrist, proper boots, helmet
9. Could depend on alot of factors... wind.. bike condition/age... your weight... I am about 170lbs and my 05 250 made it to ~120 on the speedo.. so like 105 or so in reality.. (downhill mind you, and on a very long straight)
10. You should be applying BOTH front and rear on the street... although a lot of people just use front... engine braking has mixed opinions about it.. so i wont touch that... but if you are locking up the rear... obviously you are using too much of soemthing... i do about a 65% front 35% rear combo when braking on the street... although i admit to just using the front most of the time...
11. Take the MSF course - a lot of these questions would be answered for you - and you will learn a lot...
__________________
Rides: 2005 Ninja 250 - SOLD
2001 F4i - SOLD
2003 R6 - Fun
Cage: 1993 5.0 Mustang - SOLD
2003 Tacoma - temporary...
5. When you brake, mass is shifted forward and the rear brake loses stopping power. In the extreme, the rear wheel is off the ground.
6. Hanging off the bike to the inside of a turn allows less lean angle to be needed for a given turn/speed. Within reason, the more you hang off the better, but you only need so much in a given situation.
7. Get a proper street helmet first to protect your whole face. The rest of the gear (jacket, pants, gloves, boots) will save your skin and bones.
10. Unless you're concerned about the engine stalling, keep the clutch out and use engine braking. Learn the feel of braking front and rear under various conditions. Engine braking does add to rear braking and will cause lock-up sooner than without engine braking.
__________________ Moderator - Help me fix it and riders' gear. Send me a PM with questions, suggestions, or issues.
Never out-ride your ability to react (even stop) within the distance you can see (at least on the street).
1) How many miles on tire? I'm betting it's cupped. Run your hand over it and feel for high/low/high/low on the shoulder of the tire (not the edge and not the center ... slight lean angle part)
If that's got the high/low thing going on you're cupped. A new front tire is the only thing to fix it.
1. when I let my hands off the bars between 30-50mph, the front wheel will wobble from side to side, why is this? Does this happen on all bikes? How do you deal with this phenomenon while stunting, with no access to handle bars?
2. when I try to do a stoppie, first the front tire will slighty lock, leaving a tire mark. If I stop even harder, the front wheel will wobble (before I can ever get the back tire in the air) and I feel like the bike will just fold over. i imagine I could do a better job holding the tire straight with the handle bars, but is that the solution? Do all bikes do this?
See the connection? Think you're flatspotting the tire?
Grab Sport Riding Techniques by Nick Ienatsch from Amazon.com. It talks a lot about the stuff you mentioned. It talks about how and why the bike is designed the way it is and you will understand the physics involved.
I can't answer any of your questions, but you got the BEST color scheme for the older generation 250s. Best one i've ever seen. I might get one for myself. Do you know the name of the color or the color code?
Grab Sport Riding Techniques by Nick Ienatsch from Amazon.com. It talks a lot about the stuff you mentioned. It talks about how and why the bike is designed the way it is and you will understand the physics involved.
Yes! i actually had this on request at the library, thanks for reminding me, it got there today
Quote:
Originally Posted by JW87
I can't answer any of your questions, but you got the BEST color scheme for the older generation 250s. Best one i've ever seen. I might get one for myself. Do you know the name of the color or the color code?
i know niether the name nor code nor where i could find that out, however i do know that this is not the original paint. (not sure if color was changed or just re-done, after it was dropped by first owner) but i do REALLY like the color, its even better in person.
...i know niether the name nor code nor where i could find that out, however i do know that this is not the original paint. (not sure if color was changed or just re-done, after it was dropped by first owner) but i do REALLY like the color, its even better in person...
1. It sounds like the air pressure in your front tire may be low. Check that first.
If you've done a bunch of wheelies and been setting the front end down kind of hard, you may have messed up your steering head bearings.
2. Not sure what to tell you on the stoppies. You don't have the best brakes in the world. I'd at least upgrade to braided lines in the front, if not a high quality (expen$ive) brake fluid also.
3. Depends on your tires. With good race rubber they'll let go predictably. With most street tires, it's like they get to the limit and go, "OK, I'm outta here!"
4. Practice. Lots of practice. Preferably on a dirt bike.
5. Yes. It's very dynamic. It varies with speed, brake pressure, available traction, tire condition, etc., etc., etc.
6. Quick transitions from one direction to the other. Make sure you're using your legs to move and not pulling with your arms.
7. The way you're riding? Full leathers.
8. Helmet, good bots, good gloves, full leathers, back protector. Leathers can generally be either one-piece or two-piece.
9. Sounds about right.
10. Wind resistance? Are you serious?
The rear brake and engine braking have a similar effect on the rear tire's traction.
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I too, have nothing of value to add to this thread...
10 questions...
