Busa at the Track

[COLDSTONE1300]

At this point, I still hadn't pulled the trigger. For the first afternoon practice session (for the big bikes), we all headed out. I got some clear track and put my head down, passing a number of bikes in the corners and on the brakes. When I came around for my first flying lap at speed, I painted a big darkie out of the last corner onto the 3/4 mile long front straight, got under the paint, and frickin' lit the after-burner. It looked like the other bikes were parked on the front straight as I went past. There were not a lot of people watching along pit wall, as it was just a novice practice session. The engine hit the limiter in 5th (about 190 mph actual with my gearing), and I sat up and crushed the brake lever, snapping off two down-shifts before pitching it into the first corner. The next time I came around, there was a solid wall of people standing on the pit wall, watching. I had to take a different line because I was passing so many people with such a high speed differential. The traditional racing line is to drift out towards the outer wall, away from the pit wall. I had to square off the corner and stay to the inside (near the pit wall), blow past everyone, and then after passing the last bike, move over on the brakes into the racing line to set up for turn one. I was told later that the announcer talked about nothing else, and people along pit wall were stunned. I watched video later that made my bike look like a stinger missle fired down the front straight along side the other bikes.

And Who Says the Hayabusa isn't a True Sportbike (besides idiots)?    Good job kirk and Mos!

[Kirk]

One of my goals was to show people what the Hayabusa was all about. Not that I personally was cool or fast, but just what the bike was about. I think that when most people think of the Hayabusa, they think of the posers with Neon tubes, and chrome-plated bar ends, and stupid stuff like that, or they think of the stretched and lowered bikes that take 25 mph turns at 25 mph. I wanted for them to see that the bike was capable of holding it's own in the corners and on the brakes. And I most definately wanted to make sure that each and every person there developed a very three-dimensional understanding of the difference in speed between a normal sport bike and a Hayabusa.

[eddie j]

good job Kirk-even though I am not real fast in the curves I did surprise some people at Deal's Gap on my Busa cause of that same mentality-they see so many stretched and lowered they tend to forget that it's still a sportbike.

[dcnblues]

Stock suspension on the busa is amazing and highly adjustable.  Better than anything any racers had fifteen years ago.  98% of owners I'm sure never play with the six different adjustment settings.  I'm 220 pounds and my suspension setup was done by a pro and I've had three track days and bottoming the front suspension isn't a problem.  Maybe there are some stock front springs that are weaker than the ones that came on my bike, but don't get the idea that your stock setup needs to be junked.  Clearance on the busa is fine.  Unscrew the feelers on the footpegs, get the front suspension cranked high enough that you don't bottom it, and you'll never grind engine cases or fairings.  I suspect those that do either had unusually weak front springs, or more likely had their suspensions set too soft (which is often how the dealer sets up the bike).  Very rare to hear about the busa touching parts due to lean angle.  You can put a zip tie around your fork slider.  After each ride, slide it back up.  The action of the front suspension will push it down.  Properly set up, it won't get within a half inch of bottom of tube.

Dood. That half inch at the bottom- that IS the bump stop. Spring selection has little to do with personal preference- It's basic arithmatic. Claiming or deciding that you "like" the stock fork springs isn't going to make them work any better. The flaccid stock .85 kilo fork noodles are correct for riders between 30 and 80 pounds, in their gear. My Hayabusa was about 75 lbs lighter than stock, and even with 1.0 kilo fork springs, I was bottoming the forks on the brakes some. But with stock fork springs, the front of the bike falls like a fainting goat any time you try to do any significant braking. Nobody here that has gone to the correct fork springs for their bike has had anything less than gushing praise for the improvement. There is no "adjustment" that's going to make the fork springs work. I don't know what kind of "pro" is going to be able to get you to 32-36 mm of sag in front with stock fork springs. You can crank the compression all the way in, and it may slow it down enough that you don't feel it hitting the bump stops, but it is.

My comments were not criticism, just throwing in my 2 cents.  But your comments on stock suspension confuse me.  Are you exagerating, or are you serious that you think stock busa fork springs are only correct for riders who weight less than 80 pounds?  I don't understand your comments.  I adjust (tighten) the spring preload until the forks don't bottom.  No problem setting proper sag (roughly 1/3 total front suspension travel).  I'm not talking about the compression or rebound damping, just the spring preload.  And again, I'm 220, and pass liter bikes at the track.

I'm not arguing that expensive aftermarket suspension parts wouldn't be an improvement, and feel better.  And you certainly seem to know what you're talking about, with the exception of this.  So I don't get it.  It almost seems like you know everything except how to tighten spring preload, which would explain why you're bottoming even stiffer than stock springs, and scrapping your fairing (or maybe your bike was set up with too little fork oil).  Again, I've got a plastic zip tie around the shiny smooth part of the fork tube.  No matter how hard I ride or brake, the fork compression doesn't bottom it on the tube.  I set up the suspension myself, then had a former AFM road champion tune it.  He told me I had it pretty close.  He also said he was surprised at how fast I was able to get a busa around the track (we ended up riding around a lot together that day).  I actually haven't gotten around to loosening the spring preload a little.  I want it a tad softer than its current set up for the street.

Also (for those that haven't done it yet), be aware that any given track day and how you do relative to others is a flexible thing.  My first track day I was group C with a good collection of fast liter bikes and two 750s, but none of the riders were experienced or even terribly fast.  In one twenty minute session, I lapped most of them twice.

At another track day, the other riders didn't look all that different, but they were all fast, and I held my own but sure didn't lap anyone.  The riders around you will have a big influence on how you feel at the end of the day.

[dcnblues]

One of the points people miss about getting off the seat and moving around is that you're not just moving weight to the side.  You're also trying to move weight FORWARD.  You get the weight on the balls of your feet and your hands, you get up off the seat, you slide around the tank, you grip the tank with your high side knee, and you get your center of mass FORWARD.  Take a look at the next picture you see of pro racers in action.  Their helmets are way up next to the front fairing, often where your mirror would be.

I respectfully disagree. The reason that our heads are closer to the windscreen is because our heads are lower. On corner exits, we do get as far forward as we can, to keep the front end down, but on corner entry and mid-corner, your weight should be right where it is when you're in a race tuck sitting on a bike stand, except that you will be off to the side of the bike. There may be minor variations of riding style along these lines that are neither right nor wrong, but the idea of "rotating" around the tank when getting off the seat is not a good thing to teach.

I agree with Kirk on this one.  You don't want to put alot of weight on your hands!  Actually, when leaned over in a corner you want a relaxed grip on the handlebar, allowing the suspension to do its job.  If you apply alot of pressure (weight) or if you have a "death grip" on the handlebars when leaned over, you are just fighting the front suspension, thus preventing it from working as it was designed.  You will hit bumps and grooves in the corner, if you have too much pressure on the handlebar, the suspension can't work properly.

I never said to put weight on your hands. Your grip should definitely be light enough that the front tire can find it's own angle.  That's why you need to be balanced on the balls of your feet, and your inner thigh, and highside knee.  Ideally, you have almost no body weight on the bars at all.  And isn't it Keith Code (amoung others) who SPECIFICALLY teaches the 'rotate around the tank' method?

It's basic physics that in the turn, center of mass moves to the back tire.  You need to move forward to compensate for this.  Almost any rider needs to scoot back on the seat to get into a race tuck for reduced drag.  Saying that this is the correct body position for a turn is just not right...

[02BluBlkBusa]

I got a chance to talk face to face with the Pirelli Rep this weekend.  He was at Arroyo Seco Raceway for the races.  I was in need of new race tires for the Busa so it worked out good that he was there.  Anyway, he saw that I was running the 180/55 on the stock 6" wheel.  He told me that I need to run the 190/55 for better handling.  He got all technical on me, but after he explained it and showed me the differences I agreed.  He was willing to sell me the same setup I had 180/55 sc2 and 120/70 sc1 Super Corsa for $250.  Or I could spend $300 for the new Super Corsa Pro 190/55 sc2 and 120/70 sc2.  So I got the Pro's.  Now I can hardly wait for the next track day 26 Mar.  

He also told me that the Super Corsa Pro are meant to be 35psi hot.  The tires are at there best grip at that pressure.  Told me to setup at 31 front and 30 rear cold.  Run two or three laps then recheck tire pressure and adjust as needed until I get 35psi hot on front and back.  

He was a very cool guy.  Most tire sales people are just there to push tires.  They don't really care about anything after the sale.   This guy talked with me for about 30 minutes.  Passing on his knowledge of racing and tires.  He even wants me to contact him once I get the tires on the track.  He wants to know how they feel and handle.  He is that confident in the tires.  I'm counting the days until track day (12 days).

[Kirk]

I got a chance to talk face to face with the Pirelli Rep this weekend.  He was at Arroyo Seco Raceway for the races.  I was in need of new race tires for the Busa so it worked out good that he was there.  Anyway, he saw that I was running the 180/55 on the stock 6" wheel.  He told me that I need to run the 190/55 for better handling.  He got all technical on me, but after he explained it and showed me the differences I agreed.  He was willing to sell me the same setup I had 180/55 sc2 and 120/70 sc1 Super Corsa for $250.  Or I could spend $300 for the new Super Corsa Pro 190/55 sc2 and 120/70 sc2.  So I got the Pro's.  Now I can hardly wait for the next track day 26 Mar.  

He also told me that the Super Corsa Pro are meant to be 35psi hot.  The tires are at there best grip at that pressure.  Told me to setup at 31 front and 30 rear cold.  Run two or three laps then recheck tire pressure and adjust as needed until I get 35psi hot on front and back.  

He was a very cool guy.  Most tire sales people are just there to push tires.  They don't really care about anything after the sale.   This guy talked with me for about 30 minutes.  Passing on his knowledge of racing and tires.  He even wants me to contact him once I get the tires on the track.  He wants to know how they feel and handle.  He is that confident in the tires.  I'm counting the days until track day (12 days).

This is all cool, but keep in mind one minor point: The tire vendor is not Pirelli. He's someone that sells Pirelli tires. Most tire vendors are knowledgable and helpful. They are your best source of tire information when you're at the track. They definately will have knowledge specific to your particular track. But I prefer to go to the head technical guy of the tire manufacturer's racing tire division for information to avoid the possibility of an error in third-party information.

Given my choice, I'd run a 190/55 over a 180/55 too. They last longer. They also give you a little more ride height.

Have a good time. I'll be expecting a full report.

[Kirk]

Stock suspension on the busa is amazing and highly adjustable.  Better than anything any racers had fifteen years ago.  98% of owners I'm sure never play with the six different adjustment settings.  I'm 220 pounds and my suspension setup was done by a pro and I've had three track days and bottoming the front suspension isn't a problem.  Maybe there are some stock front springs that are weaker than the ones that came on my bike, but don't get the idea that your stock setup needs to be junked.  Clearance on the busa is fine.  Unscrew the feelers on the footpegs, get the front suspension cranked high enough that you don't bottom it, and you'll never grind engine cases or fairings.  I suspect those that do either had unusually weak front springs, or more likely had their suspensions set too soft (which is often how the dealer sets up the bike).  Very rare to hear about the busa touching parts due to lean angle.  You can put a zip tie around your fork slider.  After each ride, slide it back up.  The action of the front suspension will push it down.  Properly set up, it won't get within a half inch of bottom of tube.

Dood. That half inch at the bottom- that IS the bump stop. Spring selection has little to do with personal preference- It's basic arithmatic. Claiming or deciding that you "like" the stock fork springs isn't going to make them work any better. The flaccid stock .85 kilo fork noodles are correct for riders between 30 and 80 pounds, in their gear. My Hayabusa was about 75 lbs lighter than stock, and even with 1.0 kilo fork springs, I was bottoming the forks on the brakes some. But with stock fork springs, the front of the bike falls like a fainting goat any time you try to do any significant braking. Nobody here that has gone to the correct fork springs for their bike has had anything less than gushing praise for the improvement. There is no "adjustment" that's going to make the fork springs work. I don't know what kind of "pro" is going to be able to get you to 32-36 mm of sag in front with stock fork springs. You can crank the compression all the way in, and it may slow it down enough that you don't feel it hitting the bump stops, but it is.

My comments were not criticism, just throwing in my 2 cents.

No problem.

 But your comments on stock suspension confuse me.  Are you exagerating, or are you serious that you think stock busa fork springs are only correct for riders who weight less than 80 pounds?

I'm not exagerating. They are correct for riders between 30 and 80 pounds, in your gear. If your gear weighs 20 pounds, then that means that they are correct for riders that weigh between 10 and 60 pounds. They are that bad. It's a pretty significant safety concern.

 I don't understand your comments.  I adjust (tighten) the spring preload until the forks don't bottom.  No problem setting proper sag (roughly 1/3 total front suspension travel).

You should adjust your sag in front for 32-36mm. There's no way you're going to get that with stock fork springs, even with the preload adjusters cranked all the way in.

 I'm not talking about the compression or rebound damping, just the spring preload.

Understood. You and I are on the same page.

And again, I'm 220, and pass liter bikes at the track.

That's your engine getting you past them. On track days, everybody tends to take it easy when it comes to braking, so it may not be as apparent to you as it could or should.

I'm not arguing that expensive aftermarket suspension parts wouldn't be an improvement, and feel better.

You and I are on the same page about this too. I'm not trying to make a Superbike, I just don't want anybody crashing.

 And you certainly seem to know what you're talking about,

Thank you, but I'm just trying to pass on what I've learned so that others can benefit without totalling a bike and having a collar bone plated.

with the exception of this.  So I don't get it.  It almost seems like you know everything except how to tighten spring preload, which would explain why you're bottoming even stiffer than stock springs,

I know how to adjust the preload on forks to arrive at the correct sag measurements. I also am not timid with the brakes. I was taking a lot of smaller bikes on the brakes into corners with my Hayabusa.

and scrapping your fairing

I was dragging the stator cover on the left and the right side of the fairing due to taking the bike to the limits of it's lean angles.

(or maybe your bike was set up with too little fork oil).

Possible, but not likely. Dave Hodges of GP Suspension did my forks. Several times. He holds lap records at a number of tracks. It's not unusual for people to drop a couple of seconds off their lap times after having Dave do their suspension.  

Again, I've got a plastic zip tie around the shiny smooth part of the fork tube.  No matter how hard I ride or brake, the fork compression doesn't bottom it on the tube.

I understand clearly. I want for you to understand clearly- that is the bottom of the travel. You could take the springs completely out of the forks and push them all the way down, and that's where they will hit the internal compression bump stops.  

I set up the suspension myself, then had a former AFM road champion tune it.  He told me I had it pretty close.

I don't know, man. This is like the information buffet- you are free to pick up whatever you think you can use, and pass on the rest.

[dcnblues]

But your comments on stock suspension confuse me.  Are you exagerating, or are you serious that you think stock busa fork springs are only correct for riders who weight less than 80 pounds?

I'm not exagerating. They are correct for riders between 30 and 80 pounds, in your gear. If your gear weighs 20 pounds, then that means that they are correct for riders that weigh between 10 and 60 pounds. They are that bad. It's a pretty significant safety concern.

You should adjust your sag in front for 32-36mm. There's no way you're going to get that with stock fork springs, even with the preload adjusters cranked all the way in.

Front fork stroke, according to the manual, is 120mm, so that seems right.  Now I've got to go remeasure my sag, find out if it is higher than 36mm, as you're saying it will be (pretty sure I've got that right).

And again, I'm 220, and pass liter bikes at the track.

That's your engine getting you past them. On track days, everybody tends to take it easy when it comes to braking, so it may not be as apparent to you as it could or should.

I meant I pass them on the outside of carousel curves, as well as on the straits...

Again, I've got a plastic zip tie around the shiny smooth part of the fork tube.  No matter how hard I ride or brake, the fork compression doesn't bottom it on the tube.

I understand clearly. I want for you to understand clearly- that is the bottom of the travel. You could take the springs completely out of the forks and push them all the way down, and that's where they will hit the internal compression bump stops.

Ahh.  So if true, I have been bottoming it regularly but wasn't aware of it.  Very interesting.  There's nothing I hate more than thinking you know something and finding out you had it all wrong.

I set up the suspension myself, then had a former AFM road champion tune it.  He told me I had it pretty close.

I don't know, man. This is like the information buffet- you are free to pick up whatever you think you can use, and pass on the rest.

Agreed.

[dcnblues]

dammit, I just measured and got 54 mm of rider sag, way higher than optimal.  Kirk's right.  (preload set almost to max with one stripe showing).

All right, new question: we've been talking about optimal front suspension for the track.  

Even though mine has too much sag and too soft a spring for track, mine still feels a little too tight for the street.  I guess if I loosen the preload, it'll get softer but bottom easier.  With stiffer springs, I could still have the preload set a little loose for street riding, but not bottom out as easily.  And that would be optimal for street.  Do I have this right?

[Kirk]

dammit, I just measured and got 54 mm of rider sag, way higher than optimal.  Kirk's right.  (preload set almost to max with one stripe showing).

All right, new question: we've been talking about optimal front suspension for the track.  

Even though mine has too much sag and too soft a spring for track, mine still feels a little too tight for the street.  I guess if I loosen the preload, it'll get softer but bottom easier.  With stiffer springs, I could still have the preload set a little loose for street riding, but not bottom out as easily.  And that would be optimal for street.  Do I have this right?

It feels harsh because you're bottoming it out so much. It needs the correct fork springs. It'll actually feel softer once you get your forks done. 1.0 kilo fork springs are still way softer than the compression bump stops are.

[dcnblues]

That makes sense.  Thanks for all the great info!

[rumble phish]

if anyone want's a pair of 1.0 fork springs for thier Busa I'm selling mine (Race Tech springs) to go to 1.20's


Yes, I said 1.20's.    


According to the spring chart on Race Tech's web site, I ned to use (gulp!) 1.27's!!!!!!!


1.20's are as high as they go without having custom springs made, so 1.20's it is ($130 a pair!!).

 I guess they think big boys don't ride sport bikes.

I'm selling mine for $70 + shipping in the for sale section. Only used for @ 1000 miles.

[bigman]

Where are you getting the 1.2kilo springs at, I tried to get them when I first got the new bike and was unable to find a set, and would like very much to get the heaver springs, as I am tipping the scales at around 300# without gear.

[Kirk]

if anyone want's a pair of 1.0 fork springs for thier Busa I'm selling mine (Race Tech springs) to go to 1.20's


Yes, I said 1.20's.    


According to the spring chart on Race Tech's web site, I ned to use (gulp!) 1.27's!!!!!!!


1.20's are as high as they go without having custom springs made, so 1.20's it is ($130 a pair!!).

 I guess they think big boys don't ride sport bikes.

I'm selling mine for $70 + shipping in the for sale section. Only used for @ 1000 miles.

Makes sense. Jeremy Toye is not a big dude, and he uses .95 kilo fork springs on his AMA Superbike, which is about 150 pounds lighter than a Hayabusa.

My Hayabusa was about 75 lbs lighter than stock, and I used 1.0 kilo fork springs.

Stands to reason that a more stock Hayabusa and/or a big guy would be pretty much off the chart when it comes to the correct fork springs.

[Kirk]

I don't want to get too far off subject, but it's hard to discuss spring rates without also discussing damping.

With springs as stiff as you guys are talking about, I have no idea what the damping needs are. Obviously, one would need to contact Dave Hodges at GP suspension ( http://www.gpsuspension.com ).

I think it's safe to say that any bike can benefit from being re-valved, and the further your spring rates differ from stock, the more important that becomes.

There are some Hill-billy suspension fixes out there that work fairly good. SV racers often go from the stock .70 kilo fork springs to .85 or so, and just use thicker fork oil and it works okay. Just okay.

But 1.2 kilo fork springs are pretty stiff, especially when it sounds like some of you guys are going to have the preload cranked down pretty good on them to get your 32-36mm of sag in front, and I'm concerned that the stock valving may not be enough to control those springs, and at the same time, may be pretty harsh because of the small damping holes in the rebound/compression pistons.

Stock fork valving is controlled by the sizes of the holes in the pistons. The shim stack pretty much just acts like a check vavle to keep the fluid from using both the rebound and compression holes at the same time. Aftermarket re-valving uses pistons with huge holes, putting the valving control in the shim stack, which is infinately tuneable (and a subject that I know almost nothing about). With aftermarket valving, you can have a lot of compression and rebound damping (to give good control of stiff springs and give a taut, stable, composed ride with good feedback) and still have it be much more plush than stock due to the ability of the shim stacks to deflect and dump large amounts of oil through the pistons on large, high-speed impacts (like an expansion joint or pot-hole).

Since you're already paying Dave to change out the fork springs (and oil), you're already in the forks- it's not that much more money to have him re-valve it while he's in there. Just a thought.

[Kirk]

...and if you're deviating that far from stock to fix the forks, it begs a look at the shock.

The Hayabusa shock (and spring) was designed for two-up riding, so at 200 pounds, the stock spring was still a little bit stiff for me. But with all due respects, it may be a little soft for a really big guy.

The wrong spring in the back is a pretty big problem for a racer, but it's not as big a deal for a street rider, and I don't think that it would really be a safety item (like the stock fork springs are). A rear spring that's too stiff will make the rear tire spin up on hard acceleration on corner exits while you're still banked over hard. That's why Twisted exits 100 mph sweepers sideways on the gas, painting big fat darkies with the rear tire.

I can't remember what symptoms go along with a too-soft rear spring. I know that they tend to squat on corner exits, which alters steering geometry (makes it like a chopper), reducing ground clearance. I think that they also may feel harsh in back because of the progressive suspension linkage. If it's way too soft, it may even bottom out, making the rear tire spin up on corner exits during aggressive riding (like on the track). But it can't possibly be as bad as the stock fork springs are.

[Kirk]

Back to the fork spring rate thing:

The '05 R6 weighs about 150 pounds less than the Hayabusa, and it comes with .90 kilo fork springs, which are almost stiff enough for a medium-sized guy. What would make someone think that the stock .85 kilo fork noodles in the Hayabusa were even in the correct zip-code?

[L.A. Don]

Mospeada:  I am doing a track day at Cal. Speedway on Friday.  How fast do you usually get going down the straight?  I'm lookin' at the track map and it looks like it has a huge straight-away!  

I'm just concerned about my tires as I'm sure they'll get super hot.