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 Β 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 Β 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.


7 Comments on “Suspension Tuning – Part 1: The Fat Lady’s Got Slammed”

  1. Marianne says:

    Okay, you make my head spin with your knowledge. And your ability to execute said knowledge into something that actually works and doesn’t leave left over parts lying around. You’re my hero, Em πŸ™‚

    Now work that shit and go dance! 15 more weeks?!?!

    • MissBusa says:

      I had a left-over part. It wouldn’t be proper not to. =D I show you a pic of it later…. don’t wanna ruin the surprise. LOL

    • MissBusa says:

      Oh yeah! June 12-13.. can’t freakin’ wait. And I just found out that Keith Code’s got a class there, too. So, you know what I’m going to do in 2011… I’m gonna meet my hero and learn some shit for real.

      Oh, and I made her dance yesterday. I have a story to tell, too. But I have to type that up first. Good gawd. LOL

  2. Marianne says:

    What is it with extra parts? Extra parts that are replaced or necessary are one thing, but some more like WTF did this come from. DAMN IT!!! It’s like finding the oil plug washer in your left over oil after you’ve already changed it. I have learned your finger is an adequate plug until you fix your mistake πŸ˜‰ And THAT is the extent of my knowledge.

  3. chesshirecat says:

    Nothing feels better than finding your low speed center with a bit of lowering for us short shits! (well almost nothing…).

    The perturbation of dealing with factory specs and incongruities without the factory tools and pre-loaded knowledge of the BULLSHIT, is enough to make one go mad. (I think they do things like this just to be sure the uninitiated has a problem stopping themselves from throwing wrenches through a plate glass window.)

    My brain is spinning with all the figures you worked out in order to accomplish your goal…I think I would have had to hire a think tank to work that out for me. Math sucks.

    I have enjoyed reading your account of the work…

    • MissBusa says:

      Thank you chesshirecat. πŸ™‚ I had loads of help from @mikegreenwald. I worked it out myself by reading Andrew Trevitt’s book, using the newly gained knowledge to work out what I needed to do to my bike, then running the final figures by Mike, to see if I was on the right track and didn’t have a brain fart along the way. He also made suggestions (like the lowering, which initially I didn’t want at all) and gave me advice and was the mentor to this clueless n00b. πŸ˜€

  4. chesshirecat says:

    I’ve “known” Mike for some time now…or at least I’ve been following his blog and his writings on some forums. (I guess about 3 years?) All this time, I’ve never known he was such a guru in the math department as well as the track and trail end of motorcycling.
    I knew from the tweets yall were sending back and forth there was some kind of collaboration going on, but didn’t know the entire story! The photos are just what the doctor ordered.

    Really like your post on this, I’ve gained some insight into an issue I’ve never thought of before.


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