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Discussion Starter #1
A while ago I ordered the Race Trac Gold Cartridge Emulators and Sonic Springs combination to fix the wallowing front end on my Wee. I contacted Rich Desmond at Sonic, and we decided that 0.9 rate springs were good for me. I have installed them (the installation was not that hard, except for drilling out the damper rod). But after installation, I now have too harsh a front end. So maybe someone can help me decide what I did wrong.

The install was:

2009 V-Strom DL650A
Race Tech Gold Emulators, yellow springs, stock settings (2 turns)
stock damper rods drilled out as per Race Tech instructions
0.90 Sonic Springs
12.5 wt oil (mixed 1:1 15 and 10 wts)
~450 ml oil level in each fork, measured space at 150 mm
stock spacer

I put it all together and the problem I have is that I have basically zero sag now. It is *very* stiff and this is with the pre-load adjuster all the way out. I actually measured sag using the "L1 - (L2+L3)/2" method and the calculation came out to 0.3 mm. That's not a misprint. Not 30 mm, 0.3 mm.

I am not sure how I ended up with essentially no sag, as I followed the recommendations from Race Trac and Sonic. I'm pretty sure I measured volumes and space correctly. So what do you suggest to adjust the suspension?

1. Go to lighter weight fork oil (7.5? 5?)

2. Cut down the spacer? How much? 30 mm plus preload?

3. Adjust the Race Trac emulator?

I think I am about to explore the dark arts of suspension tuning.
 

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Spring Preload.... Let's go the basics and start there. After you have installed the emulator and set the spring + preload spacer on top, how much did you need to compress the fork cap nut to fully seat the cap nut onto the fork tube? This measurement should be in the range of 15-20mm, and if you are this measurement, the cap nut is fairly easy to thread into the fork tube with the fork fully extended. The Sonic springs with the stock length spacer + the emulator should be really close to correct.

Also, be sure the emulator is fully seated on the top of the damper rod. If it is sitting off center, this will add spring preload.

Emulator yellow spring.... Try setting the preload to 1/8 turn- 2 turns is waaaay too much with the stock yellow spring. I currently have my silver (the lightest spring available) at 1/8 turn preload and it works very well.

Also, modify the emulator valve plate. Drill 2 or 3 more holes in the valve plate. The one hole in the stock plate is just not enough free flow.

Fork oil.... If you are using 10 wt, you won't notice a significant difference with 7.5 weight unless the temps are colder.


Hope all this helps.
 

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1. Contact Rich and see what he says!

I'd guess you need to reduce space length to start but that's up to the gurus.
 

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PVC pipe works great for new spacers and is easy to cut to experiment with lengths. A notch to clear the cotter pin on top works well.
 

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Discussion Starter #5
1. Contact Rich and see what he says!
Actually, I did. :iagree:

He replied this afternoon. His take is that it doesn't sound like a sag or spring rate problem, but rather a binding problem of the forks in the frame.

That's an interesting take. I'll wait till tomorrow morning, when it's not 100 deg outside, and then disassemble the front end and re-assemble, making sure to double-check all the bolts, torque values, etc. If that doesn't fix it, I'll tear into the forks again.
 

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I have a similar issue. I even laid the springs, spacers and emulator out to confirm they are the same lenght as the old spring/spacer length. I am not sure what it is (mind does not seem to be binding. The emulator settings and oil selection should only affect the action of the fork and not the static sag. In any event, even with little static sag and the preloads backed all the way out, the bike handles fine. I will be curious to see what it turns out to be for you.
 

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Discussion Starter #7
After you have installed the emulator and set the spring + preload spacer on top, how much did you need to compress the fork cap nut to fully seat the cap nut onto the fork tube? This measurement should be in the range of 15-20mm, and if you are this measurement, the cap nut is fairly easy to thread into the fork tube with the fork fully extended. The Sonic springs with the stock length spacer + the emulator should be really close to correct.

Emulator yellow spring.... Try setting the preload to 1/8 turn- 2 turns is waaaay too much with the stock yellow spring. I currently have my silver (the lightest spring available) at 1/8 turn preload and it works very well.

Hope all this helps.
I think we needed about 20 mm or so to fully seat the cap. Although it did take a bit of encouragement from a friend of mine with a rather large belly to push it down.

Yikes, the difference between 2 turns and 1/8 turn is huge. I will check for something binding, but if not then I will tear into the forks and change the preload on the emulator spring. May do that anyway.
 

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5' 9", 180 lbs without gear.
YIKES!!

Are you sure you have the right spring rate?

I am 6' - 245lbs and I am using 0.95 springs and things seem to be working well.
 

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I suspect that you'll have to exchange those springs for a set with lower spring rate.

First, try removing the emulators and set the sag right. Make some PVC pipe spacers (is 1" pipe the correct outside diameter) and cut them until the unladen sag and laden sag is right for you. If you cannot get the sag set correctly, exchange the springs to get some that work for you.

After you find the right springs, spacer length, and preload adjuster setting, put in the emulators. Cut the spacer the thickness of the emulator. You should now be at the same correct sag you had above.

Try it. If the damping rates aren't right for you, make adjustments to the emulator. Make your changes one thing at a time so you know what is working and what isn't working and can change that one thing at a time.

When you get it all right, you will like the result.
 

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0.90kg spring for your body weight is on the firm side of the range - good for sporty riding. i weight 200lbs nude, and use the same 0.90kg.

Your damping and RTGV emulator setting seem also to be on the firmer side.

But they are not completely out of wack. just slightly firm so doesnt explain why u have no sag.

My main concern is why is there next to no sag (0.3mm):confused::confused: when u sit on it:

a) incorrect math calculations - forget the maths for a minute, does the front move down when the bike is under its own weight, and when u sit on it compare to when u have the front wheel freely hanging in the air;


b) way way way too much preload - but the fact you can screw down your fork caps without giant force means it cant be too far out for that 0.90kg spring. perhaps use a shorter space with PVC pipe. I cut mine down to point where i can just screw on the fork cap without force and use screw driver to adjust enough preload to give a rider sag of about 40mm.

c) more worryingly, did u introduce some additional fictions into the system - is everything done correctly. To a "fork cap off and stroke the fork test" to see if everything is sliding smoothly.

put the bike on centrestand and support it under the bash-plate with a floor jack, so the front wheel is off the floor. Unscrew the fork caps, take out the spacers and washers(if any) as they might fall out, and use both hands to lift the wheels up and down- there should be minimal starting friction and operation smooth - otherwise there's a friction problem somewhere.
 

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Rich D,

Do exactly what Bazooka Joe says to do. He is right.

I have done A LOT of field testing on my forks. Both Bazooka Joe and I have come up with the same conclusions.

You and I weigh the same amount. I started with a .90 Sonic Spring as well. I have gone back to the stock Suzuki spring.

I have the "yellow" Race Tech Emulator preload spring installed as well. "Two turns" is waaay too much preload tension. I have "one turn" of preload using the yellow spring.

I am currently using 10wt fork oil. I am going to go back to 15wt. HARSHNESS is a symptom of not enough rebound dampening to the suspension system. The suspension is "snapping back" too quickly.

Bazooka Joe mentions drilling more holes in the top plate of the Race Tech Emulator. The stock setup has only one hole. Drill at least one more hole in the plate. I currently have four holes drilled. My plan is to braze one of them back up. I will do this when I change to the 15wt fork oil. I have tried two with good success. I went more then that just to see what would happen. Four holes is too much. Two holes works well. I need to try three holes to be able to speak about that first.





Use an airspace of 150mm between the top of the fork oil and the top of the fork tube.

Unless I missed it, I read that you drilled holes in the damper rods, but I didn't see that you had brazed closed the rebound hole too. You need to do that.

Again, "harshness" is a symptom of too quick a rebound. You will need to increase the weight of your fork oil. Changing the spring rate downward, and drilling more holes in the emulator top plate will give you some "softness" over the smaller bumps.

B.L.
 

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Watch AND study this video clip very carefully.

 

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Black Lab,

Thanks for the vote of confidence on my fork tuning.

That is an interesting video. The guy isn't measuring the rear sag exactly correctly (should measure straight up from the axle, but that's not a big deal since he is doing it consistantly). However, it was interesting that the front did not change concernably for the wide range of rider weight. Keep in mind though, that during braking, then the fork spring weight IS very important and may need to be changed for different rider weights.

That is interesting that 4 holes are too much in the valve plate, and that is good to know. I have 3 holes total- two of the stock 1/8" diameter and one hole 3/32" dia, and that seems about right. The holes are like opening up compression clickers. I saw once on the Race Tech site that the valve plates are $5 each- that might be easier than brazing/soldering them shut.

Rich D,
On the topic of fork oil, as always, watch which brand fork fluid you are using and read the bottle carefully. One company's 10wt is often quite different viscosity than another company's. You want to select fork oil which is about equivelant Cst numbers to the Torco 15 wt RFF. Make sure you are comparing apples and apples.
Read this thread for a whole bunch of emulator, oil information, and other fork tuning info.
http://www.stromtrooper.com/dl650-specific-wee-strom/56303-adjusting-race-tech-emulators-my-bike-strange.html
 

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However, it was interesting that the front did not change concernably for the wide range of rider weight.
You immediately picked up on the point that I want other riders to see and think about. It is a point that I sincerely want to DRIVE home into the minds of V-Strom riders.

In the video, three very different weight riders sit on the bike. The front sag is identical for ALL three riders. This is a VERY important point to take note of!!!!

The V-Strom IS a different bike then your standard sport bike and the standard cruiser. Why? Because the sitting position is "neutral". A V-Strom rider is not leaning forward like a rider would be on a sport bike, and they are not leaning back like on a cruiser. A V-Strom rider is right smack in the middle of the bike.

The video illustrates this beautifully by having three different individuals, of different weight, sit on the bike. The front sag did not change.

What does this mean? IT IS THE REAR SHOCK THAT IS DOING NEARLY ALL OF THE WORK!

If you do not tune the rear shock first, to your weight, and riding style, you will NEVER get the front tuned in properly!

And, to just say that, "I have the rear shock where I want it.", is not good enough! If you ride a lot of miles, over many different surfaces, (Interstate, secondary roads, gravel roads, smooth roads, pot holed roads, straight roads, "twisty" roads, etc), there is NO perfect setting. It will take a commitment of time, and patience for a rider to reach the compromise of settings that works best for them.

I am now well into my fifth season of riding my 2007 DL-650. I have 93,000 miles on my bike. I am very hard on my motorcycle; particularly when riding dirt roads, (I typically throttle up and go faster and ride harder on dirt roads then I do on paved roads!). The stock rear shock failed on me at 28,000 miles. I replaced it with a Hyperpro very basic shock. It has lasted over 60,000 miles of very hard abuse. I would NOT purchase any other rear shock because of how this unit has held up!

The rear shock I am very happy with. But, after all of these years, and all of the miles, I am STILL tinkering with the front suspension! Granted, some of it is just to see, "what will do what", (inspired by Bazooka Joe and his work), so that I can share my experiences here with other riders. Each season, my riding changes a little bit, and I change the front suspension to match it. The stock springs are perfect for me. I mostly tinker with fork oil and the Race Tech Emulator plate.

A common mistake that V-Strom riders make is to install a spring that is too stiff for the bike. What I like to tell riders is, go ahead and use an online calculator, or talk to the "expert" and let them give you their recommendation for what they feel you need for your bike. Take that recommendation and then drop down a notch or two in spring weight. If the calculator says to purchase a ".95" weighted spring, purchase a ".90", or ".85" weighted spring.

The issue with the front end dive isn't so much the dive itself, it is the rebound from the dive. If you totally remove the "dive", you are only going to ride interstate roads. Installing Race Tech Emulators, Ricor Emulators, or Traxxion suspension upgrades, (and tuning these products correctly), along with the proper weighted fork oil is the secret to success in tuning the front suspension.

Watch the video again......and again.......and again...... There are many "messages" within it that don't come right out at first.

Lastly, tune your rear shock first!

B.L.
 

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...My main concern is why is there next to no sag (0.3mm):confused::confused: when u sit on it:...

c) more worryingly, did u introduce some additional fictions into the system - is everything done correctly. To a "fork cap off and stroke the fork test" to see if everything is sliding smoothly.

put the bike on centrestand and support it under the bash-plate with a floor jack, so the front wheel is off the floor. Unscrew the fork caps, take out the spacers and washers(if any) as they might fall out, and use both hands to lift the wheels up and down- there should be minimal starting friction and operation smooth - otherwise there's a friction problem somewhere.
That was exactly my thinking. :)
Assuming the sag numbers are correct, something is seriously binding. Even the stiffest fork springs made won't result in essentially zero sag. No point in discussing springs or damping until that's sorted out.

FWIW, a 0.05 change in rate (i.e. going from a 0.90 to a 0.85) is going to change the sag about 3mm.
 

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FWIW I'm also 5'9" and 175 lbs. With Racetech .95 springs, emulators 1 3/4 turns out and 15 wt oil my forks soak up everything on the street, large or small, and the sag is adjustable with the stock preload adjusters. It sounds like there may be an assembly, spacer length or fork oil height problem, not a spring or oil weight issue.

Bill
 

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FWIW, a 0.05 change in rate (i.e. going from a 0.90 to a 0.85) is going to change the sag about 3mm.

On a sport bike.

Again, I sincerely want people to watch the video that I posted. Although a sag rate my change by 3mm by a spring weight drop of 0.05, that can't be measured on a V-Strom.

Watch three VERY different riders sit on a DL-650 with the SAME front end setup. The sag DID NOT change!

The tuning of the front end of the DL-650 is VERY dependent upon the tuning of the rear shock, and riding style of each person.

(Rich, I am not saying that you are wrong in your numbers. I do not doubt them! I sincerely believe that front end suspension issues will be solved by starting at the back end of the bike first.)
 

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I dont understand why Rich D has NO sag :confused::confused:

All the talk about tuning is about find tuning damping - which is great but dont we need to address the sag issue first.


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Interesting, you guys are using welding shut the rebound hole to firm up rebound as a means of reducing harshness on road. I tried that with 2.5wt - too harsh - with 1.00mm orifice still too harsh - i had to go to 1.75mm orifice to get the balance about right and that's with 2.5wt oil (15CST @40c) - this compares with 2.3mm stock orifice and 10wt oil. 2.5wt oil is an intiminator thing, but rebound is purely controlled by rebound orifice and oil viscosity.

must be the roads in Australia - slower rebound is not very good for bumps as the spring does not come down quick enough to remain in full contact with the roads - get's a lot worse with pothole where the first action of the fork is extension before compression.
 
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