Rear Shock/Spring Upgrade




Jay Willie

Donating Member
Registered
For starters, this is a very basic upgrade done for reasons other than the typical but still with benefits, especially for the twisties. I will say there are quite a few more things about suspension tuning (to say the very least) I don't know and don't understand, but none the less, I needed to do something different to try and help my bike so here goes:

I purchased an '07 in April of '08. It came with lowering dog bones (don't know what kind), extended swing arm (6"), lowering triple trees, and a few other apperance mods. Over the last several months, I've discovered something about Hayabusa's that has piqued my interest in the bike's ability to corner. Now to all you naysayers of extended, lowered, etc. let me just say that I am starting to realize there is a lot more to this bike than just 0-200 in a little under fifteen seconds so please bear with me. By the time it's all said and done this bike might end up back at stock height (or closer)/swing arm but for now, it's what I want to work with.

The previous owner had the arm/lowering bones and trees done straight out of the box. At some point, it appears (with the bike lowered) he shoved the rear tire up through the under tail/battery tray and then replaced the stock broken piece with an aftermarket (don't know by who or what type) and raised the bike back up. The previous owner obviously looked like he weighed less than I so after putting a few hundered 'get familiar' miles on the bike, I started doing some harder launches/faster riding (ehmm, yes officer, just under the speed limit :laugh: ) I started noticing the tag begining to resemble a rolled up newspaper when I figured the weight difference between me and the previous owner was beginning to take it's toll. So as a temporary fix, I used a drift and cranked the height adjusting nut on the rear shock down to raise the rear of the bike just enough to avoid the newspaper thing.

I've been satisfied with riding the bike that way until a few months ago when I started experimenting with corners. To enjoy the few we have in Kansas for very long usually winds up resembling what 'cruising' was like when I was in high school....four blocks of u-ies all night long, jeez was that ever exciting...NOT! I ride with a buddy who has a ZX-1400 and we'd switched off a couple of times to do the twisties....what a difference between a stock set up and my custom! This is when I decided to start getting serious with the rear suspension (I know what your thinking, Lamb, Scar, and all you other guys who could do circles around my corners, and probably while I'm cornering but again, please bear with me!)

So I contacted Race Tech and spoke with Loius Martinez and boy did he have a lot to say,"....you want to take your stretched and lowered 'busa and make it do what!?!!" (Not really, but close) Anyway, so I'm starting with the rear spring to stiffen up the rear for obvious reasons. I could start using some really cool words like fulcrum, and pivot point, and x+y to the third power, etc. but I ain't that smart about it...yet (I hope).

I present to you for your viewing pleasure....

This is the bike about two months ago....
View attachment 145731
Just getting ready to work on her....
Spring 19.JPG
(Don't laugh...it's the only place I have to work on her for now!)
A few shots of the new Eibach spring alongside the stock spring....
Spring 37.JPG
Spring 40.JPG
Before switching out the springs, I counted ten threads showing above the adjusting nut. I figured my sag rate according to the directions supplied with the kit and set the new spring accordingly. I think there are two threads showing now...
Spring 43.JPG
After the new spring, I went ahead and lowered the bike via the lowering links for now. Since I don't have the equipment to deal with a nitrogen shock, I will be sending it out later to have lowering blocks installed with the upgraded valving.

At the end of our Eureka Springs MnG MotoGP, ehmm, er, I mean, little motorcycle jaunt, Cap'n came up to the group I was sitting in and said,"Usually when people come to these things, they leave feeling like they've learned something." My response was,"I came thinking I knew something only to discover I don't know anything!" I did come away from my experience with a little better understanding of how to corner. I think I am a little better at it than what I was and I can say that the spring upgrade made the bike feel much smoother and has steadier movement through the corners than like the squishy pillow it was before.

In the mean time, I do show the bike and I will probably contented with the suspension with the bike in it's present form (don't flame me bro's!). After all it does win the shows slammed and lowered and looking like a drag scooter (obviously not much competition in this area...yet) and to be honest, I still haven't got over the look. I like it....alot.

Here's to Happy Trails!!

Eureka Love1.gif

Spring 19.JPG


Spring 37.JPG


Spring 40.JPG


Spring 43.JPG


Eureka Love1.gif
 

street racer

Donating Member
Registered
It is a gorgeous bike John and you ride it well ! On advice from several of the riders (ergo racers) at the MnG I removed the adjustable rear lowering links and put the bike back to stock height using the stock links. Immediate improvement in cornering. Tracks true and doesnt run wide. Thinking about suspension gives me a headache ! Good luck with your bike and I noticed your new avatar !:beerchug:
 

Jay Willie

Donating Member
Registered
Hey, Jack! You are far too kind!! I really had it handed to me at the MnG. I was so amazed at the riding ability of so many people and those that were riding two up...OMG!! James and Julie were railing along with Dan and Holly...those people can scoot! Friday coming back from supper, J&J were leading with Dennym next and me behind. The 'J's' were far enough ahead I thought it was just one rider...and I was struggling to keep up! (Not neccessarily saying that much!) When we pulled into the motel parking lot, I couldn't believe it...what a humbling experience.

From what I've been reading, you are definitely heading in the right direction, my friend. You have a sweet looking ride and gosh!...you're speedo goes to three hundred! :laugh: Have a great week, Steetracer! :thumbsup: :beerchug:
 

Mr Bogus

Trouble Makers Inc.
Donating Member
Registered
Hey, Jack! You are far too kind!! I really had it handed to me at the MnG. I was so amazed at the riding ability of so many people and those that were riding two up...OMG!! James and Julie were railing along with Dan and Holly...those people can scoot! Friday coming back from supper, J&J were leading with Dennym next and me behind. The 'J's' were far enough ahead I thought it was just one rider...and I was struggling to keep up! (Not neccessarily saying that much!) When we pulled into the motel parking lot, I couldn't believe it...what a humbling experience.

From what I've been reading, you are definitely heading in the right direction, my friend. You have a sweet looking ride and gosh!...you're speedo goes to three hundred! :laugh: Have a great week, Steetracer! :thumbsup: :beerchug:
I love this part... :rofl: Having ridden more than a few miles with James and Juli, they ride as a single entity.. meaning Juli knows how to ride too...

now for the scary part... I have never seen them go past the 50% mark on their riding.. James has a healthy and well deserved respect for Juli (she can really friggen punch)... :laugh: (oh and he is just plain safe on rides, never seen him ever get into trouble going to fast into a corner)

Most guys come away from a MnG with exactly the same feelings you do... "I thought I knew how to ride, but omg... these guys are friggen fast!" (I sure did after my first runs at Deals Gap)

You will remember these first trips and how much you learn for a long time and hats off to you for being open to it... I learned a lot from MnG rides and am now doing track days... (I knew there was a hidden agenda to these silly "Lets all go for a ride" things....) There are some really good riders here with a lot of good advice... Lucky left coast guys get year round riding on super good roads....

:thumbsup: to the mods.. but I bet your bike ends up stock length very soon... trying to corner a semi is a lot different than a sports car.... :whistle:
 

BMW5

Registered
Jay Willie,

I really enjoyed reading your post. I love the lowered/streched look as well, but with my weight; I need to upgrade my rear spring at minimum because I have already worn a hole in my stock undertail. I purchased a heavy duty spring from ATC and will have it installed soon. I will report my thoughts on handling and comfort after the work is done. Here is a link to my post on a similar subject.

https://www.hayabusa.org/forum/busa-mods/110145-suspension-help.html

BMW5

My Hayabusa.jpg
 

Jay Willie

Donating Member
Registered
From Mr. B:
You will remember these first trips and how much you learn for a long time and hats off to you for being open to it... I learned a lot from MnG rides and am now doing track days... (I knew there was a hidden agenda to these silly "Lets all go for a ride" things....) There are some really good riders here with a lot of good advice... Lucky left coast guys get year round riding on super good roads....

to the mods.. but I bet your bike ends up stock length very soon... trying to corner a semi is a lot different than a sports car....
Memories of so many really cool things and great people...neat new chapter in life! I like your comments on the "cornering a semi....", Randy. I am finding this to be very true. I'm still kind of hoping to wind up with something along the lines of the lowered thing with some ability to carve :deadhorse: and I'm taking my time to flex and learn, etc. I really appreciate the input (constructive) and good words, sounds like you definitely have a history in the 'busa experience and I really enjoy your upbeat posts. (Can somebody give me a clue on how to post a partial quote and include who it's by with in the quote box? Thanks in advance!)

Mr. BMW5:

I forgot to post the specs on the spring. I gave Race Tech my riding weight as 250 and indicated occasional two up at a combined weight of 390 lbs. The specs on the spring is 8.0 x 2.25" 17.8kg with a 1,000 pound weight rating. At this point I lowered the bike via the bottom hole on the lowering links and, if you look at the last photo (with me on the bike), the back wheel assembly fits up inside the rear fairing assembly quite well, ALTHOUGH, I am not using the stock undertail/battery tray. If you would like, I can post pics of the aftermarket battery tray, but I plan on replacing this with a stock assembly. For now, with the bike lowered, no bottoming out problems solo rider and that was my goal. The cornering thing was an unexpected improvement as I'm still 'on the tit' for this part of the 'busa experience. Oh, and I've lost about fifteen pounds so rider weight with gear is around 210 lbs.

I've come to understand lowering the bike via the links some how changes several geometries in the bike which I've heard have a negative effect on the orginal engineering of the Hayabusa's design. I'm certain there is truth to this statement and I haven't studied up on this as of yet. The Race Tech people recommended lowering the bike through lowering blocks inside the shock. They even sent the proper blocks, seals and a bushing but, as I said somewhere, I don't have the equipment to service a nitrogen shock.

Hopes this helps any and all interested! Have a Good 'un! :beerchug:
 

TonyMastodon

Big Blue Burrito!
Registered
Thanks Jay!!!

I made a few calls already and im getting springs ordered for the front and rear (1.1k in front and 1000lbs in rear).. thanks for all the advice!
 

jjbusa

Donating Member
Registered
how much was the spring and were did you get it? do they have a site? and was it hard changing the spring
 

Jay Willie

Donating Member
Registered
Eibach Spring was custom ordered through Race Tech Suspension. Here's the link:

Race Tech Suspension

You'll want to talk to Louis Martinez, ext 109. Cost a little less than 150.00 including shipping, insurance,etc.

I used a press and some tools I made to remove the stock spring and install the big 'un. If you do this upgrade I recommend finding a professional in your area. A thousand pound spring under pressure coming out from under it's control environment will easily break bones. Not too cool!
 

Jay Willie

Donating Member
Registered
Jay Willie,

I really enjoyed reading your post. I love the lowered/streched look as well, but with my weight; I need to upgrade my rear spring at minimum because I have already worn a hole in my stock undertail. I purchased a heavy duty spring from ATC and will have it installed soon. I will report my thoughts on handling and comfort after the work is done. Here is a link to my post on a similar subject.

https://www.hayabusa.org/forum/busa-mods/110145-suspension-help.html

BMW5
Opps! Almost forgot! Very nice looking scooter!! Me likie!! :thumbsup: :beerchug:
 

TonyMastodon

Big Blue Burrito!
Registered
how much was the spring and were did you get it? do they have a site? and was it hard changing the spring
there are so many options. I talked with Walter over at About Us
and he said we have so many places to choose from..maybe you can give him a call and he can figure something out for you (they build and tune race bikes at that shop)

i was quoted about 500 for parts and labor.
 

evolved4g63

Registered
Good cheap upgrade compared to an ohlins or penske replacement. I had a local shop switch the springs for me for 10 bucks. Good luck
 

DEMMYM

Donating Member
Registered
Daniel at Cloudnine motorsports can hook you up as well, Goldenchild here on the ORG also a sponsor, Did me right when I extended Misty and then Put a hole in the Undertail with the back tire.

Sold me the spring, then when I couldnt find anyone to swap it out, told me to send it back and he would install it on a shock he had at the shop and send it to me, This way the only down time I had was swapping my shock and spring for the one he sent me.

If you want to do the same, Just pay for the shipping and I will send my shock and spring to Daniel, You buy the spring from Daniel and he will install the spring onto my shock,
( You will have to find the price of the spring and install from him )

1000 lb shock, No worries about bottoming out anymore.

===================================================================

MISTY ALL AROUND 034.jpg


MISTY ALL AROUND 022.jpg
 

BigDiesel

Registered
Daniel at Cloudnine motorsports can hook you up as well, Goldenchild here on the ORG also a sponsor, Did me right when I extended Misty and then Put a hole in the Undertail with the back tire.

Sold me the spring, then when I couldnt find anyone to swap it out, told me to send it back and he would install it on a shock he had at the shop and send it to me, This way the only down time I had was swapping my shock and spring for the one he sent me.

If you want to do the same, Just pay for the shipping and I will send my shock and spring to Daniel, You buy the spring from Daniel and he will install the spring onto my shock,
( You will have to find the price of the spring and install from him )

1000 lb shock, No worries about bottoming out anymore.

+1 I used a Hyperco spring from HPC n Greg's shock on mine w/a 9" stretch and it ran waaaaaay better than it did on the OEM pogostik:thumbsup:
aftermarket dogbones can be somewhat flimsy-fyi-go with threaded adjustable units for strength + peace of mind:beerchug:

Hyperbike Shock 006.jpg


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