Getting Started

[r6_philly]

Stock Suspension could cause you to crash...
Most bikes out of Japan are sprung for a 150 pound rider (with gear on). Bottom out the suspension and who knows what is going to happen.
IMO learn to ride a bike that is setup right, right away. that way you have a better grasp of what the bike is doing under you.

Myself, I race on strictly a Cash basis also... I am afraid of the debt I would ring up if I didn't do it that way!  :o
And trust me when I say I am tempted to go out and buy a new bike, while taking a loan out on it...

err I weight 150 with gear on and I have never been on a stock suspension bike where I can get more than 10mm of sag. My R6's does not even go down when I sit on the bike.

If the new bikes are sprung for 150 lb rider, then when a 180 guy taking a 130 girl for a ride, there wouldn't be any play in the suspension? I find your analogy not realistic.

I always raced with a stock shock. I had it respringed this past year. after than I felt a great big difference because now the rear will move...

[lil_thorny]

Dafan,
you are an exception. All xian is refering to is most
club racers under racing conditions. ie., 200 lbs
with hot DOT's.  how often do you drag your knee
with the women on the back?  i'm not arguing, but
it is a huge difference when weight is shifted from
front to rear an vs versa when the spring rate is wrong.  for example, I myself weighed 180lbs with
all of my gear on, was running a stock shock and
spring. Then I went to an after-market shock with
a 425 .  No real difference, still spinning up the rear
coming out ( GSXR 600 ) of the corner. finally changed the spring because I was just the opposite
of xian,in that I needed to soften up the rear. went
to a 400, mucho bettero.  You have to remember,
that most guys out there are not your size, and they need stiffer spring rates so as to not loose the rear
mid-corner. just out of curiosity, what rate spring are you using? 375?  So, it isn't really an analogy, just
big-guy physics is all.  Be happy that you are a little guy.  Your motorcycle thanks you.

30.

[Gixxer124]

Stock suspensions rule! ;D

[r1owner]

Yep, just prep it and go race it.  That's what I did.  Never been on a paved track before I took my racing school.

Rode a bunch on the street but got tired of the dangerous non-moveable objects just outside of the turns.

[lil_thorny]

Kevin, Kevin, Kevin, this is why you will never catch
Stumpy.

If you would only listen to reason ;D

30.

[Xian_13]

Wow guys...
Next time I open my mouth... I will have to say exactly what I mean, you guys nit pick to much!

My comment was a generalization in regards to Stock Suspension.. that is NOT touched.

Super Dave, I understand and agree with all you have said about suspension... I stated what I did, as completely un touch suspension. Not adjustments to springs, oils, sag, or Geometry. It can be dangerous on the track. Even worst in the hands of someone not knowing what they are doing.
I said this based off of a friend that crashed at BHFs while riding a bone stock, untouched bike. He has a video of the crash showing the suspension NOT working right and bottoming out in Turn 1 prior to the repaving. While I didn't go into great detail about what I was saying, I was trying to be helpful with out being technical.

Dufan
The 150# rider and gear comment comes directly from the service manual from my bike. If you read the owners manual, it clearly states you need to change you suspension and air pressure setting before taking a passenger. That is written for people who are not planning on Riding WFO through Turn one at Brainard!

While the knowledge I have about Suspension on a bike would not fill Super Daves little toe. I do know that is the Suspension is what is keeping you on the track!

While I may have sounded like I was advising getting all After market suspension, I meant that the suspension should be setup for the rider. If that means after market stuff or not.

[Super Dave]

Wow guys...
Next time I open my mouth... I will have to say exactly what I mean, you guys nit pick to much!

... He has a video of the crash showing the suspension NOT working right and bottoming out in Turn 1 prior to the repaving. While I didn't go into great detail about what I was saying, I was trying to be helpful with out being technical.

LOL, yeah, aren't we fun to deal with?  LOL!

As for the suspension bottoming and crashing in old one...

Honestly, the biggest problem with stock suspension is that it can't move fluid fast enough.  Really, you'd want the suspension to be practically bottomed going in, and then gradually the front rises as the braking load decreases and the load it shifted to both ends of the suspension for cornering force.  

A big bump...probably hit the bump and then locked from dampening.  

Dampening is something that you certainly don't need TOO much of...that will make you crash.  If the dampening overcomes the spring...it's wrong.

But I'll agree that I would rather spend the money on suspension first thing with correct geometry on my bikes.  That's how my R6 is set up, that's how the H1 will be set up.

[K3 Chris Onwiler]

 That's how my R6 is set up, that's how the H1 will be set up.

You mean that's how your bike WAS set up.  The last time I saw your bike, it was in a muddy ball! ;D

[Gixxer124]

Like the H1 will ever see a track. ::)

[GSXR RACER MIKE]

     I took the Race Tech suspension seminar back in '98 (3 days long - 8 hours per day) and learned alot about how suspension works and why.

     I agree with Dave on the statement "Honestly, the biggest problem with stock suspension is that it can't move fluid fast enough". Current motorcycle suspension components mostly use a piston with ports thru it to control fluid flow from one chamber to another. The way the flow of fluid is controlled is by a stack of round shims which cover the ports in the piston. As the piston travels thru the shock body the fluid from one chamber travels thru the ports in the piston, deflects the shim stack (actually bends the shims away from the port and allows the fluid to pass thru the piston port), then fills the other chamber.

     The problem with stock suspension pistons is they use smaller more restrictive ports and incorrect shim stacks which are geared more toward street situations. The more restictive ports are thought by the manufacturers to be a cheap way to help reduce bottoming out the suspension during hard hits. Though this does work to an extent it also affects fluid flow during all movements, not just harsh ones.

     Similarly is the theory behind variable rate springs which get progressively stiffer as they compress, they are generally used to make up for incorrect valving in the shim stack (though the manufacturer will try and get you to believe otherwise). Without doing any valving changes variable rate springs would be a decent middle ground to improved suspension performance.

     Race Tech Gold Valve kits replace the original pistons in stock suspension with pistons that have much larger unrestrictive ports in them. The thought here is that the ports in the piston should not be used as a valve and the shim stack should be used to control fluid flow. This is done by stacking the shims in a pyramid shape with the largest diameter shim against the piston face and progressively getting smaller. To adjust the flow of fluid for each persons individual situation the shim stack is then modified by varying shim diameters, thicknesses, and quantity. Hard hits are now controlled by the smaller diameter (often times thicker) shims and are now easily adjustable if needed (unlike the smaller ports in stock pistons which can only be opened up, but how much?).

     When you compress the suspension as you go into a corner the spring is compressed and the shim stack inside the suspension controls how fast and smoothly it happens by controlling fluid flow. The problem is that the suspension will initially compress past the amount that it actually needs to be and will then rebound and the spring will begin uncompressing which is then controlled by the rebound valving on the other side of the piston. This is why stock suspension valving with incorrect springs will either bottom out under heavy corner loads (too weak a spring and/or not enough compression valving), or you will get a pogo-stick up and down action (too strong a spring and/or not enough rebound valving), or loss of traction (incorrect spring or incorrect valving not allowing the suspension to follow the road which acts similar to not having suspension at all). The ultimate situation is to have your suspension use the center third of it's travel during normal corner loads, therefore allowing a cushion of extra travel for bumps, varied traction conditions, and berms / gator strips. Your suspension should compress about 2/3rds initially, then 'set' to its' correctly compressed amount without pogo-ing up and down, all in a smooth controlled action.

     Many aftermarket suspension manufacturers have followed the lead of Paul Thede of Race Tech and now build race suspension based on these principals.

     Correct suspension, set-up, and geometry is the absolute 'must do' when roadracing motorcycles. The investment initially will make your experience much more enjoyable thru having a bike that is controllable and predictable. You can then concentrate on your riding and not be plagued by mystery conditions like lack of traction with good tires or not being able to hold your line.

[r6_philly]

I was going to say similar things but was too lazy to type it up. You go mike! now how long did that take you ;)

[GSXR RACER MIKE]

I was going to say similar things but was too lazy to type it up. You go mike! now how long did that take you ;)

 ;DLOL ;D  It did take a while, but I wanted to help a potential new racer out!