Race Tech Fork Spring Install - Squeaks

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TahoeBound

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I've seen some interesting comments on this, but no real answers. I used RT springs and US1 oil - had to cut the spacers about 2 inches. Anyway, the dang things squeak now on compression. Never had a squeak issue with stock. I've pulled apart and checked the install 3 times - everything is straight, centered & measured equal. The only thing I see is static sag appears wrong - at the max preload line (1) I'll got at least 40mm sag & it should be closer to 30mm, so it appears the recommended spring is too soft. Overall, the bike rides very well, it just the annoying squeak. Annoying enough to me that I'm ready to toss the springs and go back to stock.

The sound is defintely internal. Any realistic solutions? Wait...let me run for cover before the answers arrive! :)

 
I've seen some interesting comments on this, but no real answers. I used RT springs and US1 oil - had to cut the spacers about 2 inches. Anyway, the dang things squeak now on compression. Never had a squeak issue with stock. I've pulled apart and checked the install 3 times - everything is straight, centered & measured equal. The only thing I see is static sag appears wrong - at the max preload line (1) I'll got at least 40mm sag & it should be closer to 30mm, so it appears the recommended spring is too soft. Overall, the bike rides very well, it just the annoying squeak. Annoying enough to me that I'm ready to toss the springs and go back to stock.

The sound is defintely internal. Any realistic solutions? Wait...let me run for cover before the answers arrive! :)
by static sag are you explaining no rider, just the motorcycle weight? Because IMO 40mm, even 30mm with that much preload dialed in seems rather excessive. I set my sag (me on the bike) to about 30mm, and that is with 3 lines showing on the preload (stock springs).

I'm curious if the outside diameter of the springs are the same. Take a vernier caliper and see if there is a difference. Could be getting too much metal to metal friction.

 
edit for a Double post glitch

 
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What rate spring did you install ?

Do the Race Tech install instructions tell you to cut the spacers ?

FWIW when I installed Ohlins 1.0 springs they squeked for a bit then stopped. The 1.0 have zero preload and are just a touch harsh ( on square edge bumps ), I may switch to .95 springs with the C & R valving.

Good Luck

 
What rate spring did you install ?

Do the Race Tech install instructions tell you to cut the spacers ?

FWIW when I installed Ohlins 1.0 springs they squeked for a bit then stopped. The 1.0 have zero preload and are just a touch harsh ( on square edge bumps ), I may switch to .95 springs with the C & R valving.

Good Luck
.90 per Race Tech @ 175lbs rider. I actually ended up calling RT and Louie advised cut the spacers based on the extra length of their springs which are ~2 inches longer than stock. I'm topped out on the preload adjustment which to me suggests the springs should be stiffer (.95). In an old thread the person backed off on preload & the squeak stopped. If I back down, I'd be looking at sag ~50mm!! I put Wilburs on my '04, buttoned her up & never a friggin' issue.

Interesting too, it seems different definitions of static sag - I'm using RT's which is [fully extended - rider/bike = static sag]. Maybe I should install some of the extra spacers they sent so conceivably I can relax my preload (if it works that way). I'm sure getting tired of pulling everything apart - though becoming pretty good at it...I even have the torque values memorized :rolleyes:

 
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Check your springs, but I recall the .90 RaceTech springs being 273mm long, which is a few millimeters SHORTER than OEM Yamaha springs. You may actually need to add spacer washers rather than cut them. The RT tech probably had the 1.0 springs in mind which are much longer than stock and do need spacer tubes shortened.

Your front rider sag is best in the 40-45 mm range.

 
Race tech's definition is what I think of when I hear static sag. Static sag is just the weight of the bike on the shock/forks.

 
Check your springs, but I recall the .90 RaceTech springs being 273mm long, which is a few millimeters SHORTER than OEM Yamaha springs. You may actually need to add spacer washers rather than cut them. The RT tech probably had the 1.0 springs in mind which are much longer than stock and do need spacer tubes shortened.

Your front rider sag is best in the 40-45 mm range.
No, the RT's are longer...I measured the difference before I cut, thankfully. Sag @ 40-45mm is highest recommendation I've seen - HaulinAshe, is that personal preference or recommended somewhere? RT says 30-35mm for street...less for race.

 
No, the RT's are longer...I measured the difference before I cut, thankfully. Sag @ 40-45mm is highest recommendation I've seen - HaulinAshe, is that personal preference or recommended somewhere? RT says 30-35mm for street...less for race.
Personal experience setting up many, many FJRs. Trust me, 30-35mm sets the front end way too high and too harsh.

 
RT recommends 28 to 33% of total suspension travel as a guide to set sag. On most street bikes (with 5 inches of travel on the front) that comes out to 30 to 35mm of sag.

Static sag is with the rider on the bike BUT three measurements have to be taken to get the correct sag. The three measurements eliminate the effects of friction caused by the fork seals.

Measurements should be taken from the same 2 points for all three measurements. (you can use the top of the fork seal and the bottom of the triple clamp as an example.

Measurements are as follows:

Lenght 1 (L1) is taken with the wheel off the grouned (suspension fully extended)

L2 is with the rider on board -- push down on the suspension (about 1/2 inch) and let up slowley.

L3 is with the rider on board -- pull up on the suspension (about 1/2 inch) and let it down slowley.

Take the average of L2 and L3 and subtract it from L1. (this removes the effects of friction)

This number is the sag with the effects of friction averaged out. This number will be very consistant (within 1mm) each time you measure.

On my RT spring installation project I experimented with different lenghts of spacers until my sag was about 40mm with the preload setting on the middle line (or close to it).

The sag setting procedure should be on the RT website. Good luck.

 
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Personal experience setting up many, many FJRs. Trust me, 30-35mm sets the front end way too high and too harsh.
Excellent. I'll try that. Definitely too harsh right now going down So.Cal freeway expansion joints - I've been dialing out compression, but I'd prefer to dial out preload.

L3 is with the rider on board -- pull up on the suspension (about 1/2 inch) and let it down slowley.
Thank-you. With that explanation it finally clicked...in RT's instructions I could not figure out what they meant for L3 !!

 
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Excellent. I'll try that. Definitely too harsh right now going down So.Cal freeway expansion joints - I've been dialing out compression, but I'd prefer to dial out preload.
Go the other way and dial out Rebound (18-20 clicks) and leave Compression more mid-range (12-15 clicks). That will give you a softer ride without being "bouncy".

 
Go the other way and dial out Rebound (18-20 clicks) and leave Compression more mid-range (12-15 clicks). That will give you a softer ride without being "bouncy".
Rebound damping controls spring movement or energy. It limits how fast the spring is allowed to move the suspension upwards after compression. Rebound is easy to set up correctly if you know what to look for. The number of clicks out/in does not provide any meaningful description of how much rebound is in the “ball park.” The number of clicks varies between bikes (even the same year and model) because type of suspension oil and age of the oil (looses viscosity over time) all have an effect on rebound damping.

Here is how to evaluate and adjust rebound damping.

1. Stand next to the bike and hold it upright. Apply the front brake. Push down on the front suspension and let the bike “rebound” upwards (keep the bike upright but don’t restrict the upward movement of the suspension).

2. As the front suspension reaches the top of its travel it may bounce up and down (or not). This movement is what you should observe when trying to determine how to adjust rebound.

3. Too Little Rebound; The front suspension will rebound quickly. When the forks reach the top of their travel they will go back down, then back up. The bouncing or oscillation may take from 2 to 4 cycles (up and down) before the suspension movement stops. The “pogo stick” action of the suspension indicates too much rebound. Too much rebound will cause the ride to feel bouncy, like a pogo stick. Each bump encountered will cause the suspension to move and without enough rebound to control the spring energy the front will have excessive movement—upsetting the chassis and causing a lack of control of the bike—especially in corners.

4. Too Much Rebound; The front suspension will rebound slowly. The forks will reach the top of their stroke and stop. There will be no up and down oscillations of the suspension. The ride will feel controlled—However the spring will not be able to extend quickly enough to deal with a series of bumps. The result is what is known as “packing” where the suspension will loose travel on each bump until it bottoms out.

5. The Correct Amount of Rebound; Set the rebound adjustment so the suspension rebounds/extends as quickly as possible without bouncing when it reaches the top of its travel. A slight secondary bounce is OK. This amount of rebound is the correct “ball-park.” If your adjustment is in the ball park, further adjustment is subjective and each rider will have his/her own idea as to what’s ideal.

Note: The rebound adjustment procedure of the rear suspension is the same.

Just because your FJR has a rebound adjustment does not mean that you can get the rebound adjustment correct. Oil viscosity/age, rebound valving all effect the adjustment. In fact, many stock rebound adjusters cannot provide enough rebound damping--a common problem. That’s why Race-Tech and other aftermarket suspension providers are in business.

Even when new my stock FJR (05) was unable to dial in enough rebound with the adjuster screwed all the way in (no clicks out). I had to replace the Yamaha components with Race-Tech parts and their recommend oil to get rebound to adjust correctly. You can find lots of suspension info in Lee Park’s and Paul Thede’s book “Race Tech's Motorcycle Suspension Bible"

 
Just an interested "by-stander" of this process, since I need to try to fine tune my suspension - thanks HaulinAshe, 3dogs et al for all the great info. As the rider in the video says, it's one thing to read the info, but if you've not have much experience with setting up suspension it is pretty confusing... This demo is on a track bike but it seems like the principle is pretty universal.

For a visual demo here is a great Youtube video showing what the above description looks like, by Dave Moss (another guru in suspension tuning):

https://www.youtube.com/watch?v=brRDwt4Q2kQ&NR=1

 
Not to hijack the thread, but one of the reasons I'm currently trying to "catch-up" on the suspension tuning is because after my last tire change (again PR2s) the rear seems to be feathering quite badly, yet nothing has been changed on the bike since the new tire went on and the previous tire did not do this at all, the weight of the bike has not changed by any meaningful amount either. The current tire has only been on the bike for about 3k miles so I find it hard to believe that the Penske 8983 rear shock (which was rebuilt about 15k miles ago by Traxxion) has suddenly degraded/changed that much in the last 3k miles. The tire pressure I'm running is the same as always, 42PSI on the rear & 40PSI on the front, which I check before every ride/weekend.

Based on what I've read and seen in my searches it looks like I have somehow developed too much rebound damping? So I guess I need to click out a few clicks from the rebound knob on the Penske.

Here are the pics of the feathering on my rear tire. If anyone has any other ideas to explain this please chime in.

IMG_0618.jpg


IMG_0626.jpg


IMG_0628.jpg


 
Go the other way and dial out Rebound (18-20 clicks) and leave Compression more mid-range (12-15 clicks). That will give you a softer ride without being "bouncy".
Thanks all for the info.

The ride has improved - preload @ 42mm, rebound out 18 clicks, compression out 14 clicks. The ride has improved overall, but those freeway expansion joints are tough...the suspension could be described as bouncy I suppose, but to me its more like "very busy." Almost like my old '929 which had notoriously high compression. With the RT's I now have a range of 32 clicks on rebound...perhaps I need to keep dialing rebound out??

[update] Less rebound appears to be the answer. I've backed it down two more clicks. I feel like I'm almost there & almost have my FJR back!

 
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Not to hijack the thread, but one of the reasons I'm currently trying to "catch-up" on the suspension tuning is because after my last tire change (again PR2s) the rear seems to be feathering quite badly, yet nothing has been changed on the bike since the new tire went on and the previous tire did not do this at all, the weight of the bike has not changed by any meaningful amount either. The current tire has only been on the bike for about 3k miles so I find it hard to believe that the Penske 8983 rear shock (which was rebuilt about 15k miles ago by Traxxion) has suddenly degraded/changed that much in the last 3k miles. The tire pressure I'm running is the same as always, 42PSI on the rear & 40PSI on the front, which I check before every ride/weekend.

Based on what I've read and seen in my searches it looks like I have somehow developed too much rebound damping? So I guess I need to click out a few clicks from the rebound knob on the Penske.

Here are the pics of the feathering on my rear tire. If anyone has any other ideas to explain this please chime in.

IMG_0618.jpg


IMG_0626.jpg


IMG_0628.jpg
I would have to agree that you have too much rebound dampening.
 
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