Suspension Questions

[pimpin420]

I realize that lowering the Busa is gonna take away some handling capabilities. I lowered it 2" in the front and rear. Seems like the rear is a lil soft. I can get into the corners just fine, but seems like it doesn't wanna exit well. I have been told to tighten the pre-load up a lil bit and this should help.

These are guys that go to the track quite a bit, and not really Busa riders, so I though I would come on here and get some opinions from people in the know.

Should I just stiffen up the rear suspension(screw dial) or should I tighten up the pre-load(big nut controling spring stiffness)....

 

[Tufbusa]

Theres not much you can do to make it ride well after dropping her 2 inches. You can crank in all the preload you dare but all the preload does is raise the ride height a few mm's. And why would you want to raise it back up after lowering it?

The reason your bike takes up three lanes on corner exits is you have changed the swingarm angle from positive to negative. Your stock swingarm angle is set up from the factory with a positive angle to counter the squat when power is applied. This is called Anti-Squat, which if set up perfectly it should equally counter the squat created by weight transfer to the rear when power is applied. Once the swingarm angle reaches the negative position the chain pull actually increases squat rather than countering squat, compounding the tendency for the bike to squat under power, making a bad situation even worse. Actually, it can cause your rear shock to bottom out on corner exits under heavy throttle with the results being loss of traction.

Not much you can do to make it hold a line on corner exits. It looks cool as hell but you now have a genuine turd when it comes to corner performance  

One other point, your preload has no effect on the spring stiffness. You'll need a heavier spring to accomplish that.

 

[In10SS]

+1, what Tufbusa said. Nevertheless, I'd make sure your sag is set correctly. If you're under 230 the rear spring rate isn't that far off, and adjusting your preload correctly may still help a little. I'd seriously consider raising it 1" in the rear. If you're above 230 it's to soft and too low. You're asking for trouble if you're doing any spirited cornering. If it feels soft you could still dial up the compression damping a notch, but thats not the real fix. It'll just ride rough and still have the other issues. Be safe!

 

[pimpin420]

Thanks for the info guys!!

I'm 270, so that may be an issue as well. I realize that I was gonna lose some performance by doing this, just seemed like something was off. Just took it out and played with the compression, turned it up two notches and it made a huge difference.

Before when I would go to sit on the bike, as soon as i would sit down you could feel the rear compressing more than the front, now with it adjusted, the bike settles evenly when weight is applied. I'm not entirely sure that the guy I got from left it stock. I think I am going to take it in and ask them to re-adjust the settings back to completely stock config(in concerns to compression and pre-load settings) as I am not sure that they were ever right from the get go.

Seems like the front wheel wants to get a little light on me now though. Either way, it is definetly better.

 

[Tufbusa]

The spring is what does the work. The only thing the compression does is to slow down the speed of the spring as it compresses. It won't change how far the spring compresses only the speed of the compression.

Here is your stock factory settings for your Generation I suspension:

Rear Shock:
Compression - top adjustment - 8 clicks out
Rebound - bottom adjustment - 11 clicks out
Preload - 183 mm spring length

Front Forks:
Compression - bottom adjustment - 9 clicks out
Rebound - top adjustment - 3 clicks out
Preload - 5 lines showing

No reason to pay someone to reset your suspension to factory specs. Do it yourself.

 

[pimpin420]

Thanks alot Tuf, gonna mess with it this weekend for sure.

Let me make sure I got this straight though,
Compression setting adjusts spring recoil speed...

Preload changes the distance of travel in concerns to the spring...

Is that right?

One more thing, Is adjusting the preload gonna have a better result than just stiffing up the compression? I see how to get the stock settings, but being that I am 270 and In10SS mentioned the 230 thing, how should I go about setting it up for me?

Hopefully im not buggin too much, i'm just about ready to finish everything off(money wise) and I just want everything to be in peak performance given what I am trying to do.

 

[Charlesbusa]

Generally;

The rebound clicker controls how fast the spring uncompresses.  Too slow and the tire may lose contact with the pavement after hitting a bump, also the suspension may not be ready for the next bump.  Too fast and the bike feels out of control(moves a lot).

The compression clicker controls how fast the spring compresses.  Too slow and the suspension doesn't absrob the bump and passes it into the chasis, also causing the tire to possibly loose contact with the pavement.  Too fast and the bike may feel out of control(moves a lot).

Preload is used to set the bike's supension(sag) so that the suspension is used in the middle of its travel.  The suspension works best there.

Different springs(rate) are used to vary the amount of force needed to bottom out the suspension.  If a spring is too stiff, the suspension does not absorb the bumps and instead passes them on into the chasis making a very stiff ride and also may cause the tires to loose contact with the pavement.  A spring too soft will cause the bike to move around more and bottom out causing the tire to possibly loose contact with the pavement.

There are other uses and results, but generally this is what these adjustable features are meant to do.

 

[Charlesbusa]

Preload changes the distance of travel in concerns to the spring...


One more thing, Is adjusting the preload gonna have a better result than just stiffing up the compression?

The amount of suspension travel is set by the fork or shock.
Spring rate determines how much force is required to use up all the travel.
Preload can also vary the amount of force required to use up the suspension's travel, but to a far less degree than different spring rates.


In your case, not finishing a corner well, preload should make a bigger improvement than compression.  But in your case the problem is coming from changing your bikes geometry, lowering it.  You can mess with comp, preload, and even different springs in your shock.  But the fix is adjusting the bikes geometry, not its suspension. However, you may get the bike to feel better by experimenting with the preload and comp. It can't hurt to try. Just keep track of your adjustments.

 

[SANDFLEA85]

yes 270 has something to do with it,im 290,I just got my shock back from traxx dynamics yesterday,it now has a 1300lb rated spring on there with a 1" spring spacer.the stock shock is worthless unless you weigh 160lbs,im lowered 3" front and back and stretched 6"..get your suspension right and cornering is a non issue,I love these guys that say lowered and stretched bikes are "turds",I can assure you my bike is no turd..haha

 

[pimpin420]

Guys, thanks for all the info!!! Love this place.

I'm definately gonna try to get with someone here locally "in the know" and get them to give me a hand. I understand in theory what you guys are saying and it all makes sense, but not really sure I am comfortable enough with making the "correct adjustments" myself.

 

[In10SS]

Adjust your front preload all the way down(more preload-clockwise). This will raise it about 1/4" if your bike is at stock settings, but will definately help some. Unfortunately, @ .85 Kg/mm the stock springs are way to light for you. You'll need 1.1 kg/mm springs or possibly a 1.15, considering the lowered application. Racetech has a 1.1 and traxxion has a 1.15, either company can get you what you need. You need to tighten the rear by two full turns, compressing the rear spring (and raising preload). The adjustment range is 190 mm soft to 180 mm stiff with stock at 183mm as someone already mentioned. Take the time to determine where your rebound & compression settings are currently. Excellent discriptions & information in above posts, and 15 minutes with a screw driver will yield dividends. No easy way to adjust the rear spring, it's hammer and punch time. It may help some to unload the rear suspension, I've used a bar through the swing arm pivot supported by jackstands if no center stand. Speaking of rear springs, racetech has an eibach 16.1 kg/mm spring that would be about right as long as your swingarm is stock.

 

[Charlesbusa]

I love these guys that say lowered and stretched bikes are "turds",I can assure you my bike is no turd..haha

Most of us never said a lowered bike is a turd  

What we've said is it won't handle as well and won't have the ground clearance as a stock bike.

My bike is actually raised from stock.  I assure you that if you were to ride my bike, then ride a lowered bike.  It would become clear what we are talking about.

Even though he said its a turd, Tufbusa's advice is right on

 

[getbizzy]

Can someone post a pic of how to stiffen the rear spring? I was told it is some sort of spanner wrench that I need to adjust the spring. The dealer told me that my GenII have an 800 lbs. spring on it and if I crank it down it should stiffen to my liking. Also I would like to no what lowers the front without putting on a new triple tree. A buddy has a K8 as well, we both have stock triple trees and when sitting side-by-side his front appears lower. P.S. please post a pic of where this adjustment is located also when you all say click-in, does that mean go all the way out as in (Righty-Tighty & Lefty-Lucie) and then turn either left or right with the screwdriver? Or use the spanner wrench for the spring. BTW, where can I get the proper tool to adjust my spring (I was told that I have one in my tool pouch but that it is hard to use) I will wait for your all responses. Thanks in advance.

 

[Scar]

Charles...typically knower of all things 'busa.

 

[Deadeye]

Hey guys - here is a similar question ... Why does the manual show the same settings for single or two up riding if all the previous posts describe the requirement or consideration to get stiffer springs for heavier riders? I have my 06 lowered (one link or approx 1 in) in the rear and 1/2" on the front (cause I'm only 5'9", 180lbs) - I have always wondered ... as my wife gets on 180 plus 120 = 300lbs - yet the book shows the same settings (admittedly, I'm not knee draggin but I have run twisties with her on to the point that the rear is spinning/sliding (slightly) and leaning to the point of no "chicken strips". My questions to the dealer have been answered with "don't change anything". I have never felt the bike get "loose" or "bottom" or anything else. As you can tell, I'm not expert but always thought that adding that much weight would need an adjustment? Learning as always.

 

[Poppy]

https://www.hayabusa.org/forum/maintenance-do-yourself/89876-jinkster-attacks-suspension.html

This is some good reading.

 

[cobravenom39]

Hey guys - here is a similar question ... Why does the manual show the same settings for single or two up riding if all the previous posts describe the requirement or consideration to get stiffer springs for heavier riders? I have my 06 lowered (one link or approx 1 in) in the rear and 1/2" on the front (cause I'm only 5'9", 180lbs) - I have always wondered ... as my wife gets on 180 plus 120 = 300lbs - yet the book shows the same settings (admittedly, I'm not knee draggin but I have run twisties with her on to the point that the rear is spinning/sliding (slightly) and leaning to the point of no "chicken strips". My questions to the dealer have been answered with "don't change anything". I have never felt the bike get "loose" or "bottom" or anything else. As you can tell, I'm not expert but always thought that adding that much weight would need an adjustment? Learning as always.

I thought the same thing, too. It's a liability issue I think.
It's just a guide anyways. I would adjust as you go.