It’s Tool Time!

I’m patiently waiting on the Man in Brown to show up on my doorstep to drop off a load of (highly specialized) tools, so I can get this front suspension pain in my arse taken care of once and for all.

What did I actually put on the track at Road A? Let’s just say that I was way too trusting of a bike that my hubby had acquired for me from a dude who is a mechanic by trade and the bike in question had also been set up and raced by a local racing team.

I’m not complaining, mind you. As far as I am concerned hubby got a great deal on the R1. The added up cost of the performance upgrades alone would have set us back as much as we paid for the bike itself. I’m speaking retail cost here. When you’re sponsored you could find yourself getting these things for free. I’m sure both parties came out of this deal smiling. I know I did, and Skinny Dude with Similar Spring Rate even cut me a break and knocked another five bills off of it. But it goes to show that even though I had checked the bike over to the best of my ability, with the mechanical knowledge that I had gained thus far, some things do not become obvious until you put the beast on the track and give it as much hell as you dare. I did. At the last race of the season. Yes, the finals. I went testing at the Grand Nationals and then still entered the actual race (there are some freakishly fast dudes in A Superstock); knowing it was a really bad idea, but when did that sort of thing ever stop me? But that is a different story for a different time. Maybe I’m going to tell it someday… when I’m completely over the public humiliation I received that weekend, and deservedly so.

Candy's Fork(ed) Leg

But I digress.

Finding a rolled up piece of shop towel shoved in between the outer dust seal, the inner oil seal and the ring clip that holds the seal assembly in place was the last straw. (Somebody sneaking some leaky fork seals through Tech?) The last straw in a long line of other straws that made me say WTF!?! out loud. Every one of these straws presented me with the awesome opportunity to research and add yet another tiny increase to my MotoMech Skill. I need to develop an eye for these things, I’m starting to, but I’ve got a long way to go. Vic Fasola took one quick glance at my bike and muttered something along the lines of my suspension setup being totally fooked and my grips being a few degrees off from each other! Holy hell, I measured those clip-ons as best I could with my digital calipers, which isn’t the right tool for that job anyway. They looked even to me, hell they felt even when I was riding the bike.

Later disassembly of the front forks revealed that the preload between the two legs was differing by several millimeters between right and left, the compression damping differed by 25 clicks. Absolutely nothing was right about the front suspension setup. Not geometry, damping, preload, relative positioning, or fastening torques. Nothing. Those tubes were slid so far up the triple tree that they were in danger of giving you a nose bleed when in the race tuck. A twitchy proposition to say the least. And to facilitate this extreme lack of straight line stability it was necessary to have the upper triple tree clamp half on the skinny part and half on the fat part of the fork tube. I snapped off both pinch bolts on the right side in an attempt to loosen them. I wonder how close they were to snapping when the bike was on the race track? I don’t even want to think about that. I managed to release the left-side bolts without a snap, by backing them out alternatively a few turns at a time. The bolts showed signs of fatigue. They were bent and the threads were unevenly stretched.

No wonder the bike felt weird in the front and kind of strange in the back. No wonder I was as slow as a blob of molasses hanging out in a fridge. The bike was talking to me. I didn’t understand all this feedback I was getting through the chassis. I am slowly learning, but my lackadaisical attitude, a conditioned response to balance perfectionistic tendencies with and adventuresome spontaneity into a more sensible approach, sometimes gets in the way and slow natural progression.

I get in my own way. There. I’ve said it. I’m a brainiac klutz. Leave me to my own devices with too much time to think and too much room for self-doubt, and I’ll stumble over my own two feet and land on the mental equivalent of my JLo ass. But I own my solutions and failures. I wouldn’t have it any other way. I have to own something to trust in it. I have to test a theory and be able to reproduce the promised results on my own to fully believe it. I don’t follow blindly, unless the source has repeatedly proven itself, and even then I can’t help but feel the gnaw of insecurity. I like my variables to be assigned beforehand. I like the equation’s result to be known. But this is the real world… and constants aren’t much fun anyway.

In the end I have nobody to blame but myself; which is the preferable scenario to me. When the blame falls squarely on my shoulders I can spare myself the annoyance of being upset with someone else.

I should have done the research beforehand, educated myself on the things I was unclear on or was ignorant of and check all fasteners. Set the suspension up for myself instead of trusting “it must be right, because the guy is my height and approximately my weight and he raced it.”

However, too much theoretical knowledge without any real world experience makes my head hurt, it gets me frustrated by information overload and I end up winging it half of the time for lack of patience, time constraints, not having the proper tools, or simply by saying: “Ah, screw this, it’ll be alright.” After all, I don’t want to wrench. I want to ride!

I own it or am owned by it.

Sometimes I do find myself getting a little jealous of some of my friends who can call upon the experience of trusted others to help them along their way. I do most everything myself, and I fall down a lot. Occasionally, this gets a little old and I feel like quitting. Fortunately, I have Mr. Slow to kick me square in the leather pants when I start uttering such nonsense as wanting to quit racing because it’s such a pain in the ass in between. Hubby is EXTREMELY supportive of my racing endeavors. He is my rock. His is the hand that reaches out to help me up. He is the one who puts up with all my girly insecurities and the shit I dish out when I’m stressing, smiles and says: “I don’t care how slow you think you are, baby. I still am damned proud of you for getting out there. You are doing it. You just need to do it more. That’s all.”

He’s right. I know that on an intellectual level. Sometimes it is just hard to hold on to that emotionally when you’re down, but not out. I wish he could also be a master mechanic and a pro racer instead of just playing the role of my psychologist. 😉

My stuff is here, I’ve got to go!

17 days until race day.


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: 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…