The Suspense Is Killing Me

Getting ready to play!

Enjoying the first real spring day of the season: Fueling up for a ride with Mr. Slow.

I’m not happy. I was at first, but am not anymore. I was lubing my chain the other day and noticed that the rear sprocket is showing signs of wear, this led me to look into a gearing change, since I’ll have to replace the sprockets in the next few thousand miles anyway. This research, in turn, got my perfectionistic side all bent out of shape because I’m about to change yet another thing while I have one kink already to work out. One thing at a time, chica. One thing at a time. Thus, it came to be that I had to admit to myself that the suspension setup compromise is not working for me in the long run. But I really don’t want to go through that whole crappy fairing and fender removal process yet again. What a bummer that is. Heck, it isn’t really working for me at all, now that I had a chance to put a bunch of miles on the bike. Don’t get me wrong, I love it lowered like it is now. I’m more confident at slow speeds (even though my turns are wider than they used to be)  and I can actually flat-foot the thing in my race boots now; no more getting stuck on the incline side of a crowned road or trying to back out of a declined parking spot. She also feels more stable and planted. However, when I first started this project I hadn’t realized that maybe the adjustability range of the ‘Busa would give me problems and would lead to compromises. Lesson learned. Check the parameters before implementation to see if it’s even possible to follow through. It was a learning experience (and still is), and I wouldn’t have been able to ask the right questions at the time anyway. Yes, I could have asked for help and had the answers given to me, but that’s not how I work. I want to own my solution. I want to be guided, not shown. The Socratic Method, that’s how I like to be taught. I had to take it one step at a time, and I’m not sorry that I did. However, I am now frustrated with the current setup. The bike now corners like a bus and my arms are really getting tired from the heavy steering, at least that distracts me from my sore thigh muscles. 😉 My geometry is way too relaxed for my taste, since I am missing 10 mm of preload in the front, but the adjusters are at their limits. I don’t want to spend more money on this… I have to sleep on it, but I think the best I can do is raise the fork tubes through their triple clamp 5 more millimeters and crank in rear preload. Between those two, I should be able to affect the desired decrease in rake/trail. I’m dangerously close to getting into the no-no zone up front and I’ll blow my rear sag numbers into race territory, but I think it might just give me what I need. If not, I can always move for a reversal.


Suspension Tuning – Part 1 (Results): There’s a first time for everything…

…and then the renown goes into the crapper. Yes, I couldn’t believe it myself when I heard my own voice reverberating the dreaded words in my head: “Shit! The speed limit is too fast!” But we’ll get to that…

As I said in my previous post, I’ve done the obligatory 11-mile loop to test out my new configuration. But really that doesn’t tell you much, even though I was riding it like a jackass: extreme lane-weaving, swerves, quick-stops, hard acceleration, more stoppie attempts, more swerves… …all in the name of science. I wonder what people were thinking when they saw me scooting it down the road fairly erratically and seemingly out of control. Ah, who cares… Luckily, this road isn’t too busy, so I usually don’t have too many witnesses on my test flights.

The suspension travel: Before

The 'Before' pic: The Fat Lady's suspension travel.

The suspension travel: After

The 'After' pic: The Fat Lady's suspension travel.

Although, I couldn’t feel much of a difference, it’s much better than it was. It isn’t perfect, for perfection I’m missing 10 mm of additional preload in the front and optimally another 4 mm of fork tube raising would be in order. But I’ve reached the end of the Fat Lady’s adjustability, so this is the closest I can come to my ideal setup using stock hardware.

So, on to the story, then: It started with my usual loop, because I wasn’t really feeling up to exploring, since it’s still too cold for that sort of thing. Yeah, it was in the low 50s and sunny, but after about 60 miles of that I’m ready to go home, since I’m shivering all over. Anyway, I turn right onto the road that takes me through part of the Sumpter National Forest. It feels a little ‘bouncy’ today. This road is kind of rough for the first mile or so. It’s that cheap Aldi’s kind of asphalt, not smooth but more gravelly. You can actually see the little rocks in it. You know, shitty road. But I think nothing of it, I have never really liked the first part of it anyway. It’s bumpy, has cracks all over it in places and sports a few potholes. I don’t know why all these imperfections seem to be magnified today. I don’t like to bounce while leaning, makes me feel like I’m going to fall off. Once I get on the smooth part I open it up a little. A few more curves and the 25-mph 90-degree dogleg right is upon me. The only reason I go down this road, really. I take it at 65. I’m wider than usual, but still on my side of the road. Hmmm…. Oh yeah, I need to add a little more oomph next time, the ‘almost imperceptible’ heavy steering from the 11-mile loop is making itself known and it’s a little less imperceptible. Not a problem, I can definitely accommodate the Fat Lady. She does feel solid through that corner. She went where I put her. Smooth, but then this section of road is almost brand spanking new.

A few miles later I remember that silly obsession I have with finding that legendary ‘Kettle Creek’ road again. I google-mapped it, and there’s only one around here and it’s what I’ve long since dubbed the ‘Redneck Racetrack’, so if that’s the road they were talking about, I feel a little, well, underwhelmed. I mean I’m as horny for curvy roads as the next guy, but that really takes the cake. That’s desperation in motion. I wonder what the current lap record is. =] But I digress, so I’m off navigating by GPSr and reading street name signs, never mind the chill in the air. I take a few promising looking random turns (which is a dangerous undertaking in these parts), and a few miles later I hit the jackpot, or so I think. I quickly mash the ‘Mark’ button on my Garmin, because I need to be able to find this little piece of lean angle heaven later: Out in the middle of nowhere with no cops around to spoil the day. I have to keep reminding myself not to get too enthusiastic and outride my sight distance. I am in South Carolina after all, and a road can just decide to quit or turn into dirt or a gravel trail without warning. When the GPSr is routing this is usually indicated by incessant u-turn demands. It’s tough to behave, but I have a feeling about this, so I keep it reasonable.

Redneck Racetrack

Kettle Creek RD: The Redneck Racetrack

And with that last thought trailing, I round the next bend and find myself looking at a definite shift in surface color and quality. It seems like they redid this part, there aren’t any lines on it, but the cat eye markers are there to mark the centerline or where the centerline would be. It’s bumpy. What the hell?!? They forgot to smooth this out or what? Aren’t they supposed to do that when the stuff’s still hot, semi-viscous and smells like shit? Damn! It’s getting bumpier as I go. Hell, if I wanted to ride moguls I would have gone skiing! I’m down to the speed limit (which is 45, by the way) and still am feeling like I’m going too fast. Good gawd! In the name of all that’s holy! Just my luck, too. I find a curvy road and it’s shit; Mr. Murphy again and his asinine law. I can’t believe that I’m actually going the speed limit and am considering slowing down even further. I try to pick my way through using the smoothest path, with not much improvement in ride quality. I’m bouncing all over the place, the Fat Lady feels a lot like a pogo-stick and all this shaking is making me have to go pee. Curses! A pickup truck pulls out in front of me. For a change, I’m glad, it gives me an excuse to go slower still. Ha! I can hardly keep up with the truck. Chick on a Hayabusa is getting smoked by some dude in an old F-150 (or whatever the hell it is). Imagine that. My feelings are a little hurt. 😉 I see his rear axle bouncing over this heinous stretch of asphalt which is a road in name only. His rear tires are moving independently, rapidly hopping over the multitude of dips and peaks, the truck’s body twisting this way and that. I am almost mesmerized by the chaotic rhythm. I keep up, despite my growing nervousness and I wonder if there’s not a better way of negotiating rough roads like this. I’m really getting tired of getting slapped in the ass by my bike and putting up with all that shaking in my handle bars, trying to relax and letting the bike do its thing is getting tiresome. I shift my weight forward a little, and lift my rear off the seat. Hmmm… slightly better, but now my weight is on the bars. Little more. Now I’m practically standing on the pegs, in a half-crouch, supporting my weight by my thighs and core, knees in, but barely touching the tank. The weight is now off my wrists, fingers only lightly curled around the grips. Much better. Now my legs are acting as shock absorbers, and not bouncing around really smoothes things out a bit. Leaning into curves is an interesting feeling and I probably look like a dumbass doing it, but who cares. This is working. I feel more in control and I think The Fat Lady appreciates me not fighting her so much anymore. My thighs are getting tired; my thighs and several other muscle groups I didn’t know I had. This is great, I know I’m onto something here, since at one point I am seriously considering passing the bobbing truck in front of me, but decide against it at the last moment. “You don’t know this road, no telling what’s around the next curve.” Glad I listened to my voice of reason, because around the next corner awaits a stop sign, with not much room to spare. I soon find myself back on a real highway. Smooth, marked, clean. I pull into the next gas station without delay, since I am about to reach muscle failure and my bladder is screaming bloody murder. I take care of business, buy a drink and a small bag of Cape Cod’s parmesan cheese chips and have a seat on the curb in my bike’s parking spot. All I see around me are huge-ass trucks. I wonder why?!? An old dude in another one of those gigantic trucks, covered in red clay, pulls into the spot next to me. He gets out, big grin on his face. He says: “That is a fast looking bike. A real bike. Big. And a real-life girl riding it. Wow!” I smile up at him from my seat on the curb: “Yessir!” He’s amazed. “You really ride that thing?” – “Yessir.” – “You are a real girl!” I smile, then reply while pointing at the mud all over his vehicle: “Looks like you had a bit of fun, too.” His smile gets a little broader: “Because I’m a real boy.” I giggle. With that he goes inside. The guy had to have been in his late 70s. When he comes back out of the store, he stops and tells me that he rides, too. Then adds: “Real horses.” I tell him I always wanted to learn how to really ride a horse, but so far never have gotten out of canter. He smiles and says: “You look like a person who would enjoy riding.” We chat a little more and then he’s off again. Old guys rule.

I think it’s time I delved into “Suspension Tuning – Part 2: Damping”. Uh-huh, most definitely.

Linkage to the entire series:

  1. Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload
  2. Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is.
  3. Suspension Tuning – Part 1: Exploratory Surgery
  4. Suspension Tuning – Part 1: Let’s Go Shopping!
  5. The (preliminary) results: OMG! OMG! OMG! The Fat Lady Can Dance?
  6. Suspension Tuning – Part 1: The Fat Lady’s Got Slammed
  7. Suspension Tuning – Part 1 (Results): There’s a first time for everything…

Suspension Tuning – Part 1: The Fat Lady’s Got Slammed

After almost one whole month I finally got around to finishing my suspension project, well, the first part thereof anyway. After inadvertently having to lower her rear by approximately one inch (at least that’s what the mech told me) by replacing the stock links with the Brock’s adjustable lowering links. Of course, I hadn’t planned on that. I had assumed that the Brock’s links at their shortest would be the equivalent of the stock length, but I had assumed wrong. Maybe a pre-purchase email would have been in order. Oh well… that kind of nixed the plans to keep the geometry as close to stock as possible, unless I could somehow offset the change by raising the fork tubes through the triple clamp more.

Let’s recap: I needed to raise the fork tubes by 4 mm to offset the undesired rake/trail increase that was caused by getting rid of 5 mm of rear preload to bring my rear sag within range. My front suspension at rest was also too low, so I needed to bring that up by about 16 mm, which is done by cranking in 16 mm of preload, which in turn is raising the bike’s front up, increasing ride height (which, in my case, is also undesired); to offset that, I needed to raise the fork tubes by 16 mm. We are now at 20 mm of tube raising and 16 mm of added front preload.

That was the plan, without the rear being lowered from stock height by the adjustable links from the start. No big deal, Mike (goldiron), my resident suspension expert and all-around hero, had implored me to lower the thing by an inch or two anyway, due to my persistent short-shit problem. I wasn’t fretting it. I figured I’ll work around that and balance it out with the appropriate adjustments. Needless to say, I hadn’t really thought that through all the way. Never had I considered the adjustability of the Hayabusa’s stock hardware, or the lack thereof. Seems to me Suzuki doesn’t want us to play around with their stuff much. Case in point: a top triple clamp upper that doesn’t have holes big enough to fit fork tubes through.

I ordered myself a convertible Pit Bull fork lift stand, to enable me to unload the Fat Lady’s front suspension, so I could slide those tubes through that newly acquired Exoticycle top triple clamp upper. It arrived in the mail shortly thereafter and two days later I was ready to finish what I’ve started a little over a month ago. You have to take the fender off to use the thing on the Gen II Hayabusa. What a pain in the ass that is. And it doesn’t seem that way at first. Three screws on either side and a little bracket that holds the brake line in place. Yaright! The screws are out. Squeeze… doesn’t fit. Shit, I’m gonna scratch the hell out of my beautiful fork tubes. Screw that. Oh, I see. The little hose bracket. I stick my skinny arm up under there, between the tire and the loose fender, and grope around blindly. Hex nut. No problem. I stick a socket (minus the ratchet) up in there and remove it. Squeeze. Shit. Now what. Oh hell! There’s another brake line clamp dead center on the top of the fender. Shit. It’s a complete circle. WTF? How am I supposed to remove that. Surely, they don’t mean for me to undo the damn banjo bolts? Jackasses. Time to consult the service manual. Suzuki’s documentation sucks! Their service manual is shit. Their owner’s manual is of equal quality. What the hell do I do with “Disconnect (b) then remove fender piece.” Disconnect how?!? Assclowns. Well, yeeeaaaaah! I look at the thing. I’m cold, my fingers are cold, the wind is blowing 30 mph and I’m not getting any happier. I don’t have patience for this kind of idiocy. Hubby goes inside (apparently he can’t take much more of my antics) but returns a few minutes later: “The peeps on Hayabusa.oRg say to just cut the damned thing off. It’s a Gen II thing, they got cheap and used plastic rivets.” Not good enough! That’s not what the manual says. As crappy as the thing is, they do tell you when you need to replace removed fasteners with new ones, because said removal process destroys said fastener. I feel around some more, frustrated. As the anger grows, so does my grip strength. I can’t squeeze the bottoms together (this is one of those fasteners akin to wall anchors, they go in easy one way, then lock into place by expanding flanges.) Aha! “Hand me the damn needle nose pliers!” I yank on the thing then stick the pliers in between the plastic ring and the fender and squeeze while yanking. I had previously tried it from underneath, with not much luck. Pop! It’s out. w00t! 45 minutes on just the fender removal. I still have to get the infernal plastics off. But I didn’t have to destroy the fastener, like it had been suggested on the .oRg.

Hubby puts the ‘Busa on her new front stand. I don’t have enough junk in my trunk to do it myself. I tried. I need a longer handle. Pit Bull makes them (“ask us about our longer handles, when you desire more leverage”, I should have, but I thought the standard handle would do, after all it’s the front not the rear of the Fat Lady. WRONG!) I’m getting a longer handle eventually. I hate not being able to do it myself. 😐

The Fat Lady's newly lowered front.

A closeup of the Fat Lady's newly lowered front.

I’m becoming quite the expert in fairing removal (if I have my brain in gear and don’t try to do the layers out of order, that is). The fairings are off (and although they are supposed to be in seven pieces, not counting the four pieces in the front wheel well, for me they don’t disengage from each other, they come off as one.) I also have to remove the ram air intake ducts to get enough clearance to the lower pinch bolts to use the torque wrench. We loosen the six pinch bolts. Two on the top triple clamp, four on the lower triple clamp. I was worried that the tubes would slide out once released, but they don’t. They are actually kind of hard to move, even with the bolts almost backed out. This is a job that can be done alone, contrary to what I expected. 20 mm is all we can safely raise the tubes in their triple clamp before we run into the no-no zone (the clamps have to stay on the smooth part, and that’s not negotiable according to the service manual.) It takes a while to get both sides exactly right. Hubby is pushing them up through, then I use the soft side of a rubber mallet to slowly pound them back down into their final position, which coincides with the line between the smooth and grooved parts of the forks. Since they don’t slide very easily this is a tad of a push-pound-push proposition. We finally get them as close as we humanly can. I used electronic calipers to check them; to my best recollection there is a difference of 0.2 mm between the right and the left side. Close enough. I think there are bigger inconsistencies in her chassis alignment out of the crate.

The right fork tube cap: Before

The right fork tube cap: Before cranking in preload

Now, to crank in preload. We need 16 mm to offset the change in ride height, and MORE importantly, to raise the bike on its suspension so it moves the travel up the shock to bring my sag within range. And this is where the fun starts. I have three lines left. To crank in preload the adjuster is turned clockwise which makes the thing disappear into the fork tube cap (for some reason I had it in my head that it would back out). 6 mm of the required 16 mm is all I can do before it bottoms. Drat!!! Oh well. Now it seems that my geometry is seriously relaxed from stock. Oh well. I have maxed out the rear. I have maxed out the front. There is nothing left to adjust. Preload at full-on in the front; preload at full-off in the rear. Fork tubes raised as far as they can safely go. I’m not happy. Shit! Well, off to go for a zip-tied test ride through the same 11-mile loop I’d done previously.

The left fork tube cap: After

The left fork tube cap after cranking in preload

I reduced my effective ground clearance from 4.7 inches (stock, but I don’t know where Suzuki measured this, I’m assuming in the middle) to 3.25 inches at its lowest point (in the rear). She’s 4.125 inches in the front and 3.5 inches in the middle. So I’ll have 3.5 inches before I bottom out and drag hard parts, namely the exhaust. I hope I can get this puppy down the driveway without wrecking my ass. I get my gear on and back her into the street. I’m a little nervous. I go slow, I expect to bottom the thing on the curb, but I don’t. So far so good. I stop briefly to push the zip-tie up against the fork seal and take off. I take it easy at first. I don’t trust the bike. I’m doubting myself. Not my calculations, but the compromises I had to make with the lack of adjustability of the hardware. I’m expecting all sorts of weird shit to happen. But it doesn’t take long to start trusting again. I can’t really feel any significant difference. WTF? The most difference I could feel on this quest for a personalized suspension setup was when I picked her up from the shop after they put the lowering links on for me and consequently dropped her ass about an inch. That was sweet as  hell. I’m a little disappointed in what little effect all that knuckle-busting for hours in the driveway had. But I’m also glad that I really couldn’t feel a difference. That means I at least didn’t screw something up and turned the Fat Lady’s kitten manners into a salivating hellcat.

There is a slight but noticeable heaviness in steering, but that is to be expected with the resulting (and undesired) relaxation in geometry. Hell with it. She’s a drag bike at heart anyway. I have land speed racing aspirations, so I can cope with that. Yeah, I’m a twisties girl at heart, but I can work it. I never experienced a ‘flickable’ bike. I’m used to manhandling massive hardware around turns. No biggie, I have forearms that won’t quit. =D  It’s only slightly worse than it was stock, barely perceptible. She does feel more planted and stable due to her lowering, and I feel more comfortable and in control at slow speeds. So overall, I gained more than I lost. Way more. The only way I can fix this is by replacing stock components, and that seems a little costly at the moment. Will the gains even be worth it? Is it something I should consider, given my newly acquired taste for rapid acceleration and top end speed? I can always get a cheap track bike to satisfy my need to dance through curves. We shall see. I don’t even know yet. I do enjoy wrestling a Hayabusa through the north GA mountains. The Fat Lady can dance, but you got to work with her, she has rhythm but she needs a firm lead. Go in early, come out late, and you better have your line right the first time. LOL Impressive for a skinny runt like me, or so I’ve been told. If anything I do enjoy making this shit look good.

Linkage to the entire series:

  1. Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload
  2. Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is.
  3. Suspension Tuning – Part 1: Exploratory Surgery
  4. Suspension Tuning – Part 1: Let’s Go Shopping!
  5. The (preliminary) results: OMG! OMG! OMG! The Fat Lady Can Dance?
  6. Suspension Tuning – Part 1: The Fat Lady’s Got Slammed
  7. Suspension Tuning – Part 1 (Results): There’s a first time for everything…

The Fat Lady’s Laying Low

The Fat Lady's slammed!

The Fat Lady's good side: after lowering the front.

The Fat Lady's slammed!

The Fat Lady's bad side: after lowering the front.


Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is!

This would have been a heck of a lot harder and not nearly as easy without the help of Mike who is totally awesome and my hero! Kudos, dude! 🙂

I’d (Almost) Rather Watch Paint Peel Off The Walls:
I’m not enjoying this whole suspension thing one iota. Generally, I like technical stuff like this, but for some reason, this isn’t doing it for me. I think I’ve found my own personal Kryptonite. It is so boring, I don’t even want to think about it too much for fear of putting myself to sleep. I’m at work, I can’t afford to take a suspension-induced cat nap. However, I’m also too much of a perfectionist to simply let it fly; to just say screw it and leave it alone in the name of ‘it’s been good enough so far’. On the other hand, I really have to fight the temptation to ‘do my own thing’ and instead force myself to stick to the ‘Rules Of Ideal’ laid out in Trevitt’s book, while I am mentally sorting through how to affect the desired changes before actually touching the adjusters on the bike. I have to keep reminding myself that I do not yet have any ‘applied knowledge’, any idea how the changes I am proposing will actually translate into the real world. In other words, I’m yet too ill-informed (read: ignorant) to make a sound judgment call and to deviate from the guidelines set forth. Maybe that’s why I’m not enjoying this as much as I should, I feel caged in by perimeters and my brain can’t go on a mathematical exploration. Soon, I hope, all in due time. And it takes too freakin’ long. It’s like working out. Painfully slow progress, without immediate gratification (aside from the endorphin high, maybe.) Patience…. Arrgh, there’s that word again!

‘The Conundrum’ or ‘Trying To Keep My Feet On The Ground’
My front sag number is good. It is above 30mm, 42mm to be exact. However, my rear sag number is at 25mm. That may be good for the racetrack (25-30mm), but the range for street riding is 30-35mm. The rear free sag is also out of its ideal range of 5-10mm and stands at 11.5mm at stock settings. I think I have the rear figured out.

The rule is as follows: If you want MORE sag, you need to SUBTRACT preload. If you want LESS sag, you need to ADD preload.

Hence, to bring my rider sag up to 30mm from 25mm, I need to subtract 5mm of preload. Now to get rid of 5mm worth of preload shouldn’t be all that complicated, and it has the added effect of lowering my ride height, which in turn relaxes the front-end geometry. It also should take care of that annoying 1.5mm of rear free sag overage and put it within range.

Adding preload does not compress the spring inside the shock more; well, it would if the shock was either topped or bottomed out. It instead raises the bike on its suspension. Removing preload has the opposite effect: it lowers the bike on its suspension. You can clearly see that playing around with preload settings is one way to adjust your ride height. Just make sure you do it equally in the front and the rear, or you will change your geometry, which will change the way your bike handles. The rule here is as follows: Lowering the rear will relax geometry by increasing rake and trail, which enhances straight-line stability, but steering will be heavier. Raising the rear will make the geometry steeper – more aggressive — by decreasing rake and trail, which leads to quicker steering at the expense of straight-line stability.

Personally, I want one (the lowered ride height), but definitely not the other (relaxing the geometry). The Fat Lady is already a bit on the heavy side when it comes to steering. I don’t want to add to that, so it stands to reason, that I must offset this increase in rake/trail numbers with the addition of a little preload up front. Or conversely, I could raise the fork tubes in the triple clamp to offset the undesired change in front-end geometry. Cranking in preload would raise the front of the bike, which in turn raises my ride height. No-go. This leaves the only viable option: Raise the fork tubes to keep the geometry the same, which also has the added effect of reducing ride height.

As with the rear, adding preload raises the front of the bike; removing preload lowers it. But when you lower the front-end by raising the fork tubes in the triple clamp, the geometry is sharpened (decreasing rake/trail) and when you raise the front of the bike by lowering the fork tubes in the triple clamp, the geometry is relaxed (increasing rake/trail). This is opposite of what happens in the rear. Think of it in terms of a triangle: With A being the front axle, B being the rear axle, and C being the top of the steering head. Connect the three points and you can readily see how slightly moving one point or altering the length of one side has an effect on the others. There’s more to it than that, but for now let it suffice.

The path to be ventured down in the quest for a personalized suspension setup has been made clear. But by how much should I adjust? Generally, raising the fork tubes by 4mm in their clamps will result in a 1mm decrease in trail. How much trail offset could subtracting 5mm of rear preload really do? Can’t be much. Doubtful it’s more than 1mm, probably just a fraction thereof. I guess, I could figure this out with a few calculations of the geometric variety, but I’m way too lazy for that, although I’m entirely anal enough to see myself doing just that… if I wasn’t already half-asleep by the concept to begin with. Obviously, I can’t keep the geometry entirely stock, so decreasing trail by a mil or whatnot doesn’t really phase me. Not right now. As long as it isn’t an increase. Cornering with the handling of a minivan? Sure. Never drove anything smaller anyway. Going around a curve in a bus? Do NOT want. First problem solved.

So, Here’s How It’s Gonna Go Down:

  1. Lessen the rear preload by 5mm.
  2. Raise the fork tubes in the triple clamp by 4mm to affect a 1mm trail decrease to offset the slight increase from step 1.
  3. Go for a test ride.

But… The Fat Lady Is A Little Weak In The Knees
Technically, that would be her elbows, if she were to be properly antropomorphosized. However, that would be messing up my play on words, so the knees it is.

The front is a different story, though. Even though the sag number, being 42mm, is above its suggested minimum of 30mm, I would like it to be less. The front is already in danger of bottoming out, and I wasn’t even riding it all that hard when I went for my zip-tied test ride to check used suspension travel. Have I ever bottomed it? I don’t think so. I don’t even know what that would feel like. The result is loss of traction, but there are a multitude of reasons for losing traction, only one of which is bottoming the suspension. I would think I would notice the upset, but I can’t be sure of that. I could go out and try and do it on purpose, but I’m too chicken for that. Plastics are expensive, and I still haven’t repaired all the kisses from the last time I bounced the suspension. ;P

In order to move the travel up towards the middle I’d have to dial in more preload. Well, crap! Here we go again with the ride height increase. Can’t do that, unless I wanna start riding in hooker boots. Even though Icon makes a really cool pair that would do just fine. =D Those would go great with that Hayabusa vest I got for Christmas, too. Hmmmm…. Where was I? Oh yeah, I ‘member now… suspension travel. The Fat Lady’s at rest at 42mm (apparently I weigh ten mil, I like that way better than pounds, especially if you don’t tell anybody your spring rate =D), with the free sag being at 32mm. The halfway point of total travel, which is 116mm, is at 58mm. Looks to me like we need to crank in 16mm of preload, to raise the Fat Lady up on her fork tubes from 42mm to 58mm. Yeah. Not happening. I could offset the16mm ride height increase by raising the fork tubes by an equal amount and we’d arrive at a nice 20mm adjustment: 16mm to offset the added preload and the 4mm previously dialed in from the rear adjustment. That would effectively decrease trail by less than 1mm total. The Hayabusa’s trail is listed as 3.9 inches at stock settings, converted to metric that’s 99.06mm. I don’t even know if I have enough room between the actual top triple clamp and the top cover. And why in the hell didn’t Suzuki make the holes big enough for the fork tubes to fit through? Their band of merry lawyers decide that we needed a way to lower the front end about as much as we needed a top-speed unrestricted bike? I’d get rid of the blasted thing, if it weren’t for the small inconvenience of the clip-ons being attached to it. What brainiac came up with that idea??? Probably the same asshole who thought black plastics would be awesome under white paint.

Here’s How We’re Gonna Rise To The Occasion:

  1. Take the cover off and measure the clearance between it and the fork tube caps. If it’s 20.5mm or more, proceed to the next step. If it’s less, proceed to Step 7.
  2. Raise the fork tubes by 16mm to offset the added preload to prevent the inevitable ride height increase.
  3. Crank in 16mm of preload.
  4. Measure rider sag and free sag to ensure that the numbers are still within their respective ranges.
  5. Go for a zip-tied test ride. If all checks out, proceed to the next step.
  6. Get a New York style cheesecake and celebrate the completion of the first part of this odyssey. Stop. You’re done for now. Next up: Damping.
  7. Go for a ride to Greenville, SC.
  8. Buy a 2010 BMW S1000RR in Acid Green. 8)
  9. Go for a spirited ride!
  10. Damn, this thing comes with a suspension, too. Take it from the top…

My Work Here Isn’t Done (Just Yet):
I ran this ‘proposal’ by a very dear Twitter friend of mine, @mikegreenwald, who kindly offered to help me sort out my suspension woes and be my technical advisor. J He checked this thing for me, to make sure I had my facts straight and my train of thought was in the right direction. Then he gave me an alternative course of action, mostly to keep me firmly grounded. Here’s what he suggested I’d do, considering that I can go from tip-toeing to flat-footing the beast depending on the footwear I’m wearing any given day. Then there’s the matter of that awesomely sweet, but too tall, Suzuki OEM gel seat I got for Christmas. I had to take it back off, because I could only barely back the bike out of my own driveway in my Sidi boots. :/ Here’s what he suggested I’d do first: Mechanically lower The Fat Lady.

  1. Get dog bones (lowering links) for the rear and drop her ass by 2 inches.
  2. Get 1-inch bushings for the front, to stick under that dreadful top triple clamp cover to make room for raising the fork tubes in their clamps to drop her 1 inch in the front.
  3. Get an adjustable kickstand, so the newly lowered Fat Lady won’t be tempted to take an asphalt nap while I’m not around.

This will ensure that I can have both feet firmly on the ground, even with the gel seat, no matter what boot I’m wearing. It will also lower her CoG (center of gravity), which is a good thing, but this, obviously, comes at the expense of reduced ground clearance. This will set me back by about $285, if I get all three parts at the site Mike hooked me up with. I was encouraged to go cruise the web for myself and he also told me to sleep on it. So I did (both).

Sometime The Next Morning (At Work):
Hmmm… I’m at work. I’m getting paid to… well, currently I’m getting paid for suspension tuning research. Ha! That makes me a professional by definition. Cool. 8P So, I’ve looked around online to see what’s available in the way of lowering my bike mechanically, then I’ve slept on it. Now, I’m sitting at work, tweaking this 2nd draft of my blog post and mulling it over.

Any solution that I come up with has to adhere to ‘The Fat Lady Prime Directive’. Which is a self-imposed rule that states that anything put on the bike has to

  1. improve performance, ergos, or riding quality;
  2. cannot hinder performance, ergos, or riding quality;
  3. has to be of equal or higher quality than the OEM part it replaces;
  4. can’t weigh more than the OEM part it replaces;
  5. be a Farkle (functional sparkle) rather than just a Pretty (non-functional, cosmetic only).

I think I’m going to break Mike’s idea down into two parts with a little tweak thrown in and merge it with my ‘proposal’. We’ll call this the MiMo Hybrid ;P:

‘I See That 165 And Raise You… 165’ or ‘The MiMo Hybrid’
I’ve decided against the lowering bushings. That will definitely get my front-end lowered by that inch Mike was suggesting to me, but it doesn’t leave room for more adjustability or fine tuning later. I will still not be able to raise the fork tubes any higher, since the OEM top triple clamp is retained. I want this fixed. I hate limitations that are there for no reason other than being there. It’s a matter of principle, like that X-TRE to derestrict the bike. But now that I have land speed aspirations, this actually has moved from principle to the realm of necessity. Anyway, that top triple clamp has either got to go or I need to have the holes drilled out in the OEM part to accommodate the 50mm fork tubes. Which one I’ll do depends on several factors, primary of which is cost. Secondary is time. Obviously I can’t wait around for a few days for them to mod the thing, I’m a commuter. I gotta have my bike. Besides, three days without riding and I’m in danger of nutting up and risking being stuffed into a straight jacket by the good folks in white lab coats of Milledgeville. 😉 The custom top triple clamps that meet my standards can be had anywhere from $165-$349, and I’m currently leaning toward the $165 model, since it’s skeleton and thus weighs a lot less than the OEM. Looks sharp, too. But I haven’t seen a pic of it on a Gen 2 Hayabusa and don’t know if — when all put back together – it would clear the fairing or the Double Bubble windscreen. More research is needed before I settle on which I’m going to end up ordering.

I will then go ahead with my proposed suspension adjustments. I’m too curious to see my work in action. I can’t help myself. I put in all this brainpower, and I need to see my narcoleptic time spent in action and see for myself how it translates into ‘real world’ application. This is my maiden voyage, after all, I need to finish it.

Once I’ve played around with the new settings, and had time to delve into damping forces a little, I’ll order the lowering links. However, I don’t think I’ll be going with dog bones. I want more control over my adjustments to satisfy my inner control freak and the touch of OCD I’m blessed with. Again, I would like to leave my options open, because I don’t know what I may want to do in the future. I may want to slam it all the way down, then I’m stuck buying different links. Or I may decide I don’t like a 2-inch drop in the rear and want it adjusted to 1 ¾” instead, then what? I want full adjustability. And it has to be somewhat simple to do. Like the link Ducati puts on some of their bikes. Brock’s makes a set of ‘Window Links’ that seem to fit the bill. (I just hope I’ll be able to check out without adding that Alien Head full exhaust system to my cart, too.) The links also run about $165. I see a pattern forming here. Along with the lowering links of choice, I will also get that adjustable kickstand, which also costs… wait for it… wait for it… $165. What’s up with THAT? Again, more research is needed before I finalize my decision on which parts I’ll actually end up with.

Now, I’m going to employ Mike’s suggestion of the 1-2-inch drop in the rear, and the 1-inch drop in the front, and feel that out. Then I can put that awesomely trick gel seat back on and roll it in functional style (until my ass gets too hot in the summer!). =D

[Pics will be added later, too awkward on the BlackBerry]

Linkage to the entire series:

  1. Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload
  2. Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is.
  3. Suspension Tuning – Part 1: Exploratory Surgery
  4. Suspension Tuning – Part 1: Let’s Go Shopping!
  5. The (preliminary) results: OMG! OMG! OMG! The Fat Lady Can Dance?
  6. Suspension Tuning – Part 1: The Fat Lady’s Got Slammed
  7. Suspension Tuning – Part 1 (Results): There’s a first time for everything…

Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload

Consider this Miss Busa’s version of CliffsNotes of Andrew Trevitt’s book “Sportbike Suspension Tuning – How To Improve Your Motorcycle’s Handling And Performance”. All the stuff online is confusing, and some of it is downright wrong. Buy the book, it’ll clear up any misconceptions and it’s actually easy to understand. It’s best to read it once all the way through to get a general idea of what you’re getting yourself into. Reread, break it down into parts, make notes or highlight the important stuff, get things straight in your mind, formulate your game plan, invite a couple of friends and just do it. I believe that this is just like any other thing a m/c newbie finds confusing at first, although it is way more involved that most stuff! Do it, and it will slowly become clear. It will start falling into place, and eventually there’ll be nothing to it anymore. I’m not afraid to screw things up and I have a game plan. Let’s get cracking:

SPORTBIKE SUSPENSION TUNING

Quickie Pointers:

  • Make one change at a time.
  • Document everything!!!
  • Understand in technical detail how a suspension works internally and be better equipped to understand how adjustments affect the machine and why.
  • Suspension setup is a compromise between several factors.
  • Different situations (ideally) require different suspension settings, i.e. drag racing, track days, playing in the twisties, commuting, etc.
  • Rider sag or sag is the amount the fork and shock compress when the rider sits on the seat.
  • Free sag is how much the spring compresses under the bike’s weight.
  • Rake is defined as the angle of the steering head relative to a line drawn perpendicular to the ground (usually between 20 and 25 degrees).
  • Trail is the distance from where the steering axis intersects the ground to the front tire’s contact patch directly below the axle (usually between 80 and 110mm).
  • Steep front-end geometry (with small rake and trail numbers) gives light, quick steering at the expense of stability.
  • Relaxed front-end geometry (with high rake and trail numbers) results in heavier steering but more stability.
  • Steep, aggressive geometry may lead to headshake when going over bumps or when accelerating out of a turn.
  • Increasing ride height results in steeper rake and reduced trail.
  • Raising fork tubes in the triple clamps results in steeper rake and reduced trail.
  • Preload does not increase the spring rate, or the spring’s stiffness, for that the spring has to be replaced.
  • Preload is a measure of how much a spring is mechanically compressed when the fork or shock is fully extended.
  • Preload is mostly used to change the suspension’s range of operation within the total travel available.
  • Topping or bottoming out the suspension will cause a loss of traction and upset the chassis.
  • An ideal suspension setup uses almost, but not quite, the full range of travel.
  • F = k * x (Force exerted = spring constant * distance) <~ linear spring rate
  • The spring rate of a coil-bound spring is infinity.
  • Damping controls the speed of the wheel’s movement; the spring controls the distance the wheel moves.
  • Compression damping controls how quickly a spring can compress.
  • Rebound damping controls how quickly a spring can extend back to its original length.

Part 1: Rider Sag, Free Sag, and Preload

Measure FRONT RIDER SAG:

  1. Have two friends lift the front of the bike by the clip-ons.
  2. Measure the amount of exposed inner fork tube, between the slider and the axle casting (for inverted forks). Call this measurement L1.
  3. While one friend supports the bike from the rear, sit on the bike in full gear, in your usual riding position.
  4. The other friend gently lifts up the front of the bike and lets it slowly settle on its suspension. Measure again. Call this measurement L2.
  5. Gently push down on the front of the bike, and let it slowly rise up. Measure once more for L3.
  6. Sag = L1 – (L2 + L3)/2
    • Front rider sag should be no less than 25mm for a race bike
    • Front rider sag should be no less than 30mm for a street bike

Below these numbers the fork is in danger of topping out on acceleration, which hinders traction and can cause tank slappers as the wheel continuously contacts the ground.

If your measurements fall out of range, adjust your preload: stiffer (clockwise) for less sag, softer (counter-clockwise) for more sag.

Measure REAR RIDER SAG:

  1. Have a friend hold the front fairing to steady the bike.
  2. Measure the distance from the axle directly up to a solid point on your bike’s subframe or bodywork. Call this measurement L1.
  3. While one friend supports the bike from the front, sit on the bike in full gear, in your usual riding position.
  4. The other friend gently lifts up the rear of the bike and lets it slowly settle on its suspension. Measure again. Call this measurement L2.
  5. Gently push down on the rear of the bike, and let it slowly rise up. Measure once more for L3.
  6. Sag = L1 – (L2 + L3)/2
    • Rear sag should be 25-30mm for the race track
    • Rear sag should be 30-35mm for street riding

If L3-L2 is more than 25mm for the front end, or more than 5mm for the rear end, there is too much friction. Investigate.

If your measurement fall out of range, adjust your preload: stiffer for less sag, softer for more sag.

ADJUSTING PRELOAD DIRECTLY CHANGES THE BIKE’S GEOMETRY!

  • Adding preload to the fork springs will raise the bike’s front by the same amount. As long as the suspension isn’t topped out, dialing in more preload will not compress the spring more, but raise the bike on its suspension and equal amount, raising the ride height. Likewise, taking preload out will lower the bike on its suspension. Same goes for the rear shock.
  • Add preload equally, front and rear, so that the front and rear sag numbers change by the same amount.
  • Bumpy surfaces need more sag and less preload.

Adjusting REAR PRELOAD:

  1. As a measure of preload (on most Suzukis) record the distance from the top of the threads to the top of the two rings.
  2. Mark one of the tabs of the bottom ring with a Sharpie, then tighten or loosen it in one-turn increments as needed.
  3. Measure your setting after you lock the top ring in place.

Before riding attach a small zip tie to the shock shaft, if you can access it. It may be difficult do to the spring and bump stop. This will give you an indication of how much travel you use.

Adjusting FRONT PRELOAD:

  • Some adjusters will move in relation to the cap as you turn them, you can record the number of lines showing on the adjuster as your measurement. Otherwise, turn the adjuster all the way in, clockwise, counting the number of turns until it lightly bottoms. This is full-stiff.

Before riding, put a zip tie around an inner fork tube and snug it up so that it doesn’t move on the tube. Slide it up against the outer tube’s dust seal. The zip tie will indicate how much suspension travel you use in each riding session. You can keep track of this number by measuring from the zip tie to the axle casting (inverted fork).

Checking FREE SAG:

  • Take the measurements the same as for rider sag, but measure L2 and L3 with no rider on the bike.
  • Free sag should ideally be between 5-10mm.

I’ve Got Her Number!

Here are my numbers. Everything is still at stock settings. What is painfully obvious is that The Fat Lady’s a little bit weak in the knees… or would that be her elbows? Something needs a little adjusting here. And I wasn’t even riding her all that hard. :/ No time now, however, but I will post my progress as I continue on my quest to wreck a perfectly acceptable setup. ;P I still need to measure the threads showing above the top lock ring on the monoshock, I procured myself a metric ruler, just for that purpose and I couldn’t get the damned zip tie around the thing, I’m gonna try again with a longer and skinnier one, maybe I can get it in there, somehow, someway. I’m just too curious to let that one rest. *sigh*

Gen 2 Hayabusa Stock Suspension Settings

Here are my numbers...

Zip Tied ...and in danger of bottoming out.

The Fat Lady's a little weak in the knees...

Linkage to the entire series:

  1. Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload
  2. Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is.
  3. Suspension Tuning – Part 1: Exploratory Surgery
  4. Suspension Tuning – Part 1: Let’s Go Shopping!
  5. The (preliminary) results: OMG! OMG! OMG! The Fat Lady Can Dance?
  6. Suspension Tuning – Part 1: The Fat Lady’s Got Slammed
  7. Suspension Tuning – Part 1 (Results): There’s a first time for everything…