|Topic Review (Newest First)|
|27th November 2019 04:44 AM|
For a regular street going SV1000
Forks at standard height in clamps.
With a 1.0kg/mm spring I would be setting total front sag starting point to 38mm. The soft top out springs give you a few extra mm to add in, so often 38-40mm is a good base line. If you have stiffer top outs installed that are the same length, set to 36mm.
On the rear
What shock length are you running? Is you unit ride height adjustable? I ask because if the shock is shorter than stock the rear will not work well and might feel overly stiff and chassis will behave weird.
Free sag if the spring is close in range should be 6-12mm range and a total sag of 30-34mm should be a good starting point.
|27th November 2019 04:29 AM|
What length are the Sonic springs ?
Stock springs for the 03 model, and i thnk all are the same, has a wear limit of 290mm minimum, and the Racetechs that i ran were 310 long, so i trimmed just under 20mm off the spacer.....(i thnk mine stockies were 292mm long)
Similar with the GSXR front end i am running now..... i think i had to take 8mm off....
|26th November 2019 04:45 PM|
Right... I think I've got the fork oil level correct. Right now it's got the stock spacers in there... Sonic 1.0Kg springs..
Wintertime is almost upon us here in the US Northeast (today is warm, at 60 deg. F! Probably the last before we get heavy frosts and they muck up the roads with salt brine) so I should be able to get down with the suspension both front and back soon.
Uhm, for starting purposes... could someone provide me with baseline SAG numbers?
|25th November 2019 02:18 AM|
When i mentioned spacer, that was for the front forks.....
When you change from an OEM spring to others, the new spring is quiet often different in length, normally it will be
Stock fork springs are usually prorogressive style and are tightly wound at one end and the wire is thinner.
Because of the length difference, you cut the extra length of the new spring off of the spacer tube that is installed on top of the spring.....
The more openly wound thinner wire also displaces less fork oil, and therefore the oil height needs to be brought up (less air gap) to compensate....
|25th November 2019 12:27 AM|
|China Greg||I guess I'll just have to do me some CIPHERIN', Uncle Jed!|
|23rd November 2019 05:11 AM|
It would be interesting to see what the eye to eye length is.
Fully extend rear and measure.
Set total sag to 30-32mm
Now measure unloaded sag. If the spring is in the zone I would expect you to see 8-12mm. If less or none, this can be a sign of spring being too light.
Having way to much total sag causes the rear linkage to operate in the higher rate region and also prone to blowing through the existing travel and hitting the bumper. This can make the bike feel extremely stiff, ride way into the travel along with wiggles that can happen in the chassis from heavy weight distribution on the rear. This is even further aggravated by a shock length that is too short. Then with such small sag in the front, makes more of an issue.
Just my 2 cents...
|22nd November 2019 07:55 PM|
|22nd November 2019 07:46 PM|
First, I realized my spring rate numbers were off:
Checking my notes and the Penske manual, the shock actually has a 400 spring in there, after changing from the original 475. Still... it's quite less than what you're running (500).
Also, my rear sag numbers were not accurate. I get confused... I mistakenly didn't lift the bike off the ground (as the Penske manual calls for "A"), but rather just lifted the rear gently and then lightly settled it for the first number. Then I hoisted my carcass on-board for "B".
So, (until I can get another couple of assistants), I can assume that my rear sag is likely over-limit, as with my (incorrect) method we got about 45mm.
I don't have a measurement for this. (I don't recall there being any installation problem from being too long... but this was three years ago).
Shock spacer... not familiar with this part; I have the Penske manual in front of me and can't see what this would refer to..(?)
I did buy this Penske 8975 off of Ebay, used.. so it's possible that the length or adjustments have been futzed-with... But again, I did have it rebuilt at Penske before use. Hmm.
But I DO recall one thing: last year I reduced the rebound in back to almost it's max (out)... and the handling (warble) improved noticeably.
|21st November 2019 11:35 PM|
|21st November 2019 08:55 AM|
Interesting. I donít weight quite as much as you and run a much heavier rear spring. My commuter is set a bit stiff because I often have 20-40lbs of motorcycle parts and work stuff loaded on.
With stiffer fork springs I often have to run more total sag on the front because of you measure the free length with wheel off the ground, the stiff spring, and soft top out springs make the measurement a bit longer than normal. My SV runs about 40mm total in the front due to this and I run a total of about 32mm in the rear.
It seems to me that your bike might be riding pretty tall in the front and low in the rear. I still am not quite sure why you canít seem to get proper sag from a 375lb/in spring unless it is too long. I think I am on a 500lb/in or 525lb/in. I canít remember. What shock length are you running?
|21st November 2019 07:23 AM|
Hmm, I don't think this is likely; I have some decent experience of installing tapered head bearings in the past, and I was quite careful with their bottoming squarely. Also, this ..warble.. has been around for quite a while before I swapped the head bearings out. The old ball assembly WAS quite heavily notched, but when I changed it over, the Warble did not change. (a big disappointment!)
YES! This is a major symptom! At most lower speeds I don't notice this problem that much, but get up to 60 or more, it becomes more obvious, especially with wind turbulence or road surface flaws.
I do have the CNC tubular handlebar conversion, AND a low-slung Corbin seat, which puts me in a weird squat position sort of like a dog with it's paws on the table! I'm working on lowering those pegs... But I AM a pretty large load: 6'1" and 270 pounds. I did try going back to the stock clamp and clip-ons... that didn't help.
In front I have Sonic springs at 1.0kg as I remember... with a Gold Valve kit.. I think running 5 Wt (maybe 7.5 I'd have to check the notes). I get about 25-30mm sag up front.
Could this be an overly-stiff spring rate out back? Or, is it possible the shock length is too high? It's been a while...but I THINK it was the same as stock when I first installed it, pretty sure I would have checked that carefully three years ago.
Thanks for the help, guys. I really like my SV, but this Warble is drilling me!
|20th November 2019 02:09 AM|
I have seen issues with tapered bearing before causing some strange issues. I have seen several sets installed that were not properly seated in the frame or could not be properly seated due to them going in slightly sideways causing some aluminum to get cut out and wedged beneath the bearing seat causing it to be off axis slightly.
If this is the case you can never seem to get bearings tensioned properly. They either seem too loose or too tight.
There are lots of things that can cause issues such as you describe and you are checking many of them.
Other suggestions from folks also seem inline.
Here are my additions.
Tires and tire pressures
Too much damping in steering can cause oscillations.
Aero dynamics can play a big part. My bike with upright bars can get a bit of wiggle in turbulent rough air when in the vicinity of large trucks.
Under sprung rear can cause issues also because of load transfer to the rear. The other way around also. Wow, 375 lbs/in spring! How much sag on and then off the bike do you have? How is the front sprung? How is the chassis geometry in comparison to stock?
|18th November 2019 11:59 PM|
I have always installed them (no forks in the triples) and tightened the threaded collar with my fingers only, the pain that the notches generate i senough to stop you going too far, then swing the triples back and forward to get a feel of the movement, then, place the washer on top of the first collar and tighten the second collar with a gentle tap of a punch....
Otherwise, weave in the front end CAN be be caused by the back end, tail wags the dog typ eof thing...
Rebound damping can be the culprit, assuming all other things are set properly, like the front fork protrusion and spring preloads....
A bit extra rebound damping on the rear can help.
Also, if the front end is too steep (forks too far through) or way too shallow (opposite) then this could be the problem too...
|18th November 2019 08:39 PM|
|18th November 2019 06:19 PM|
Speaking of bearings... I replaced my steering head bearings with tapers about a year ago. I'm rather Old School (some just say OLD).. bikes in the deeper past used Ball Thrust bearings, and I always assumed tapers were superior in that application.
Now..I'm having doubts. I've owned this K6 for six years, and as long as I can remember it has always had this weird, unsettled , warble just at the centerline, most notable at highway speeds, especially if their is wind turbulence (while passing a truck) or maybe some pavement flaws. Sort of an...imprecision.. tendency to wander slightly. Drives me nuts.
When I changed over to tapers I found the old balls & races in there were badly notched. AHA! This will cure it now! Not so.
I have rebuilt and even replaced my steering stabilizer: no change.
I've checked for swingarm bearing play: none found.
I rebuilt the front forks and checked the tubes for deflection: straight.
Tires have been changed and wheels are true.
I'm thinking, maybe aerodynamics; I have a CNC top clamp handlebar unit in there, brings me up a tad from the clip ons.
I also have a Penske shock out back, which always seems stiff, even adjusted all the way out (and I have decreased the spring rate from 400 to 375 lbs)... maybe the rear being stiff will affect the front stability?
Hmm... other than that, could it be the TAPERS in front? I can't see how, physics speaking... but MAYBE.
Anyone had any similar issue? With tapers or with Centerline Wander?
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