spring sag

dmallord

Registered
heya guys,

i tired to set the front "sag" on my 04 with 17k on the clock. what i found is that the weight of the bike alone eats up all my desired value + some! i turned the tensioners all the way in... still drops tons. i talked to a bike suspension guy, and was advised that i will NOT get the desired value from stock busa springs.

is this correct? oh yeah... i weigh in at 180.

please advise

david
 
Something isn't right, you can get proper sag on stock springs at 180lbs.

How are you measuring and supporting the front?
You also need to do the front and rear, Having one perfect and the other off will still result in a poor ride.
 
for the front i pulled all the way to full extension, then measured from the bottom of the tube seal down to the casting. i then put a zip tie around the tube. sat on the bike. this time measure from the bottom of the zip tie to the casting. the difference being total sag? 30-45 mm desired? im like double that.

yeah, i know that i should do front and rear. when i measured the rear, it came in on the stiff side. we are getting rain this weekend, so no ride for me. but, i would like to get it sorted by next weekend.
 
for the front i pulled all the way to full extension, then measured from the bottom of the tube seal down to the casting. i then put a zip tie around the tube. sat on the bike. this time measure from the bottom of the zip tie to the casting. the difference being total sag? 30-45 mm desired? im like double that.

yeah, i know that i should do front and rear. when i measured the rear, it came in on the stiff side. we are getting rain this weekend, so no ride for me. but, i would like to get it sorted by next weekend.

You need to measure the thickness of the zip tie too then if you're doing it that way.
The top of the tie is what touches the bottom of the seal, which is where you said you measured from to start with.
If the rear is stiff too you need to back some preload off the spring.
Having about 3 threads visible above the top of the lockring will get you in the ballpark. Then you can make small adjustments.
35mm to 40mm is where you want to be front and rear for street riding.:beerchug:
 
thanks sixpack,

so, if my front IS too soft... should i match the rear to the front until i can have new springs installed?

she used to be lowered 2 1/2 in the rear, and 1 in the front. i put the stock dogbones back on the rear, and left the front alone. ive been to the canyons a few times like it is, and it is night and day from when lowered front and rear. because i cant stop wanting to "fix" my bike, i have been searching suspension tuning... which brings me ultimately here...
 
thanks sixpack,

so, if my front IS too soft... should i match the rear to the front until i can have new springs installed?

she used to be lowered 2 1/2 in the rear, and 1 in the front. i put the stock dogbones back on the rear, and left the front alone. ive been to the canyons a few times like it is, and it is night and day from when lowered front and rear. because i cant stop wanting to "fix" my bike, i have been searching suspension tuning... which brings me ultimately here...

How was the front lowered? If the forks were slid up in the trees there's no extra wear on the springs.
Have you also not since raised the front back up too?
Was the previous owner significantly heavier than you?
 
I'm going to bed, goodnight and good luck.
I suspect an old man from Washington will be along shortly to set you straight anyway.:laugh:
 
heya,

yes the forks were slid in the trees. i left the front down with the idea that it would have the same effect as lifting the rear on a stock bike.



i dont know about the prior riders weight (ebay).
 
I don't mean to hi-jack your post but I have a very similar problem and as I was about to post a question, I saw your post.

My problem is that I set out to set my suspension sag today and for some reason I'm way off on the fork.

I cranked the tension all the way in and I'm still left with 50mm worth of sag and 40 mm of static sag. I weigh 210 with gear on...the guy I purchased the bike from was a lot heavier than I am but I can't believe that spring wear would set in.

The bike is a 2005, bone stock except for Yoshi CF cans 10k on the odometer. I'm not interested in a track ready set-up...my style of riding is more on the aggressive sport touring side, but I still feel the front end a little weak in the knees. Any advice would be greatly appreciated.
 
I was able to set my sag on the rear but not able to on the front of my 09 at 8K miles, but I am around 255-260 suited up. Springs do make a difference on handling if your sagging.
 
heya guys,

i tired to set the front "sag" on my 04 with 17k on the clock. what i found is that the weight of the bike alone eats up all my desired value + some! i turned the tensioners all the way in... still drops tons. i talked to a bike suspension guy, and was advised that i will NOT get the desired value from stock busa springs.

is this correct? oh yeah... i weigh in at 180.

please advise

david



"is this correct"

https://www.hayabusa.org/forum/maintenance-do-yourself/89876-jinkster-attacks-suspension.html

Yes it is. The fork springs are too soft. They use up 50+ MM of sag simply unladen. The stock springs are .85 kg/mm to get the proper laden sag with my 240lbs ass I use 1.1 kg/mm springs.

RT - Digital Product Search

Here's a good video, it's a 600 but the same principles apply.


Buy Andrew Trevitt’s book – Sportbike Suspension Tuning: How to Improve Your Motorcycle’s Handling and Performance. Read it, learn it.

Sportbike Suspension Tuning Book Review - Motorcycle USA
cheers
ken
 
heya,

thanks for the link. i have watched this one. ok... so my stock front springs are too soft. should i match the rear to the front until i can afford to respring?

thanks for the help guys. how cool is it that the busa can be tweaked to whatever degree we choose! :beerchug:
 
"is this correct"

https://www.hayabusa.org/forum/maintenance-do-yourself/89876-jinkster-attacks-suspension.html

Yes it is. The fork springs are too soft. They use up 50+ MM of sag simply unladen. The stock springs are .85 kg/mm to get the proper laden sag with my 240lbs ass I use 1.1 kg/mm springs.

RT - Digital Product Search

Here's a good video, it's a 600 but the same principles apply.


Buy Andrew Trevitt’s book – Sportbike Suspension Tuning: How to Improve Your Motorcycle’s Handling and Performance. Read it, learn it.

Sportbike Suspension Tuning Book Review - Motorcycle USA
cheers
ken

Yep, I also had to go up to 1.1kg springs at 250#. 0.85kg is good for a nice ride on the highway. Find the correct spring rate for your application

SonicSprings.com
 
heya,

yes the forks were slid in the trees. i left the front down with the idea that it would have the same effect as lifting the rear on a stock bike.

That will roughly have the same effect as raising the rear. Unfortunately it reduces ground clearance in the front and the busa is prone to dragging stuff when the front is lowered. Your best bet is to return the forks to their stock position in the tree and raise the rear with 1" raising links.

cheers
ken
 
heya,thanks for the link. i have watched this one. ok... so my stock front springs are too soft. should i match the rear to the front until i can afford to respring?

Because the spring rate is an inherent characteristic of the spring the only way to match the spring rates is by changing springs. Contrary to folk wisdom, adjusting the preload has no effect upon the spring, it simply changes when the fork/shock rests in it's travel.

More preload there is less distance for the fork/shock to compress and more distance for the shock/fork to extend.Decreasing the preload has the opposite effect.

It's a good idea to use the rebound damping to get both ends of the bike to rebound at the same speed. In that sense it is possible to match the front and rear.

cheers
ken
 
I don't see how proper sag can't be had with stock springs with only 17k miles and a 180lb rider???

I'm 195lbs in my leathers and I have 34mm of front sag on my gen2 with stock springs, and I could have gotten more.
 
I was able to set my sag on the rear but not able to on the front of my 09 at 8K miles, but I am around 255-260 suited up. Springs do make a difference on handling if your sagging.

YOU are just too big:laugh:, and will need to change fork springs.
The OP should not at 180lbs.:beerchug:
 
Lamb weighs in at 205 and he changed his to .95 in the front. Anyone who weighs more than 150 pounds should put the proper springs in.The rear will be usable for you without any changes. It may need to be dialed in, but its not gonna give you the sag numbers of the front.

If you wanna ride the mountains with authority you have to raise your front to the stock or 1/2" down only. Anymore and the ground clearance is affected enough to drag hard parts.

RT - Digital Product Search
 
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