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harnois

Moving Forward On Corner Exits

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I recently switched from a gsxr600 to a gsxr750. Not that I'm obsessed with power or anything, it's just that a good deal on a good 750 track bike came along, and hey it's something different. Now the 750 offers some new and interesting challenges, perhaps even more so because I only weight 155 pounds.

 

In the turns I'm sitting on the back of the seat, which is fairly textbook stuff I believe, and it feels good, but as I gradually power up out of the turn I eventually get to a point where I'm full throttle, still a bit leaned over, and ... still sitting on the back of the seat! In smoother corner exits I can feel the front wheel skimming, no wieght on it, under full power in 3rd gear in the power band. On bumpy corner exists, it's bouncing all up in the air and twitching and generally scary! Not working. And there's other corner exists where even though I'm already full throttle, I also need to countersteer heavily, like entering "the snake" at VIR, and if I'm countersteering while the front wheel hits a bump and comes up, well, that's how tank slappers get started...

 

So I need to get to the front of the seat on the corner exists, and when I did that all these problems went away. But the problem I have is figuring out at what point do I transition from back to front of the seat and how do I actually do it without upsetting the bike by yanking on the handlebars? I mean if I move forward early on during the exit, I'm still in the corner, don't really want to be moving around on the bike and mess'n with the handlebars at those lean angles, but if I wait until later, the power is already on big time, and the only way I can see to move forward is to pull myself forward with the handlebars, which seems like a really bad idea when the front is already light and it could introduce some unintentional countersteer and/or pull the front up.

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Could you move forward on corner entry?

 

I try not to move back and forth once I have turned the bike. Seems to me like any kind of movement once your in the corner would be difficult without upsetting the bike.

 

Better yet, rather then correct a handeling problem (bike running wide on the gas) by moving around, I might try an adjustment to the bike instead.

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I agree with Stuman on this. Try and take out some of the rebound damping on the front end.

 

Not to insult you or anything, but this is accomplished by turning the screw at the top of the fork leg counterclockwise. Try 2 turns out on each fork, then go 1 turn or even 1/4 at a time. I'm also assuming you have regular forks (not the new BPF Showa stuff) and that the bike has the proper springs for your weight.

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I think I have a solution. A sandwich. You can do one of two things with it: eat it, or jam (or some styrofoam) between your butt and the back of the seat. You need more weight on the front. I can't speak on the suspension. I'll be learning that after I attend CSS in October.

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Jaybird - why would you recomend taking out rebound damping from the front of the bike to resolve the issue being described? I don't understand? Less rebound would allow the front to extened more and might make the problem worse by adding trail and removing weight from the front of the bike.

 

I was thinking the best thing to do would be to raise the rear ride height or add rear compression damping.

 

If you were going to do anything to the front I might add rebound in an effort to keep the front end down.

 

 

As a rule of thumb, if a bike has a handeling problem on coner entry, change the front. If the problem is on coner exit, change the rear.

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Because he talked about the front being twitchy. I reasoned that he needs more front tire time on the tarmac.

 

I've never heard of the rule of thumb you mentioned, so I can't speak intelligently about that.

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I think I have a solution. A sandwich. You can do one of two things with it: eat it, or jam (or some styrofoam) between your butt and the back of the seat. You need more weight on the front. I can't speak on the suspension. I'll be learning that after I attend CSS in October.

 

Dani Pedrosa uses foam at the back of the seat to push him forward on the bike, I also saw quite a few girls using it at the nurburgring earlier this month!

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I think I have a solution. A sandwich. You can do one of two things with it: eat it, or jam (or some styrofoam) between your butt and the back of the seat. You need more weight on the front. I can't speak on the suspension. I'll be learning that after I attend CSS in October.

 

Dani Pedrosa uses foam at the back of the seat to push him forward on the bike, I also saw quite a few girls using it at the nurburgring earlier this month!

That's where I got the idea. I was thinking he needs more weight on the front if he's working the corners well, and the front end in coming up when he's accelerating.

I can't figure out how a front end adjustment would change things. If anything, maybe softening up the rear?

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I think I have a solution. A sandwich. You can do one of two things with it: eat it, or jam (or some styrofoam) between your butt and the back of the seat. You need more weight on the front. I can't speak on the suspension. I'll be learning that after I attend CSS in October.

 

Dani Pedrosa uses foam at the back of the seat to push him forward on the bike, I also saw quite a few girls using it at the nurburgring earlier this month!

That's where I got the idea. I was thinking he needs more weight on the front if he's working the corners well, and the front end in coming up when he's accelerating.

I can't figure out how a front end adjustment would change things. If anything, maybe softening up the rear?

 

 

Softening the rear will take more weight off the front. Check out Stuman's suggestions earlier in the thread, I was thinking the exact same thing he was.

CF

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You think you have problems with the front coming up on that 750 my zx-10 putting out over 160hp on the dyno is insane in 1-3 out of the corners. I have to have my weight up front or all that bike wants to do is wheelie. Not to mention I'm the same build as you 155lbs...I don't adjust my BP from front to rear in the corner...no way...I get 100% set up before the turn, and that includes the beginning, middle and exit (power on) of the turn..

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Thanks for all the suggestions, guys! Keep it com'n.

 

So regarding suspension, I was thinking, yeah like some have said I could raise the rear by reducing sag or by increasing ride height (the bike does have an Ohlins rear shock with the adjustable shock shaft length). I could lower the front by reducing the ride height (raising the forks in the triple clamps). I could also increase front sag which would make the fork springs softer at top out so maybe it would float a little better. And while jaybirds suggestion of reducing front rebound damping got a bit of flak, I can see where you're com'n from there, just to give it chance to stay on the pavement better, but that's if it's moving at all which it might not be if topped out. The idea of increasing rear compression damping - interesting idea! I can see how that could help by helping to keep the bike tipped forward on bumps.

 

But all suspensions adjustments aside, there'll always be a way with a 750 (and a 600!) in lower gears to get the front too light, and getting to the front of the seat on exits therefore will be an advantage, right? And surely sitting at the back of the seat during braking is better? And sitting at the back of the seat for the turns seems better because I can lock into the tank with my knee better, can get better hang-off body position, better front/rear weight distribution for cornering, easier to transition left to right in the back and forth sections, more leverage for countersteering, etc. Surely, fast guys on 1000s are moving back for braking and turning but forward for exits, right? Although I notice some riders at the front of the seat in the turns, it always looks pretty awkward to me.

 

The idea of using the foam behind my butt would be good if I were intending to stay at the front all the time. But the dilemma is that I want to be at the back during braking and in the turns but at the front on the exits, and how can I make the transition without upsetting the bike when the power is already on? Maybe it's just a matter of timing, like figuring out when to make the transition back to front, just after I start to stand it up a bit but before the power is full on.

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My experience from racing a ZX-10, regardless of BP, the front wheel is going to get light. It's going to bounce on the bumps and get real twitchy when it's light. One way to stop it is more throttle to get the front wheel in the air. Really, this is the precise reason these bikes need steering dampers. What can you do as a rider that will provide a damping effect on this? Have you done level 1 at the school?

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So if you move forward on the bike in an effort to keep the front end down, what effect will that have on rear traction and is that effect optimum on corner exit?

 

:)

 

Things to make you go hmmm :)

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Hey Stuman or Cobie, do you think that the "pick up" drill (end of level 2) or the "hook turn" (I haven't gotten to this level, but I understand it weights the front end?) would help with any of this?

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Hey Stuman or Cobie, do you think that the "pick up" drill (end of level 2) or the "hook turn" (I haven't gotten to this level, but I understand it weights the front end?) would help with any of this?

 

 

Well, not really. The hookturn is typically used in the beginning or middle of a turn to help the bike turn sharper with less lean angle. The pickup drill is used on the exit of the corner, but you kinda need to have the corner more or less finished before you start to pick the bike up.

 

The problem the OP described is that unless he gets all over the front of the bike, it will not finish the corner and runs wide on the exit.

 

 

You know something that I learned when I switched from a 600 back to a 1000 is that you can not ride the bikes the same way if you are trying to go fast. On a 600 you always work to get the throttle pinned early in the corner. Often you can get the throttle to the stop very early in a corner on a 600 simply because it does not have as much power. On a 1000 you have to change your line a bit, get the bike pointed before you start your drive. It might be that the OP needs to take this into consideration.

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Hahaha, "Often you can get the throttle to the stop very early in a corner on a 600...". I must be doing something wrong.

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