Suspension overhaul time

Outbackwack

Howard
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OK, so I was looking at downsizing to a 650 or something and nothing panned out (yet), so I decided that if I hung onto my 2008 ST1300A I would overhaul the suspension this winter because I've never had confidence in the handling of the front end... way too wobbly over bumps and in turns over uneven road. My bike has never felt "planted" to me no matter how things are dialed in. So, it's time for an overhaul...

I'm planning on forks, rear shock and All Balls bearings. I weigh about 165# with my gear on and ride 95% solo. I am an average rider and have never scraped a peg. I enjoy spirited riding but have no desire to push the limits. Race Tech is a fore-runner at this time but I'm always open to options. I will be reading a lot of posts on suspension as well. I am wondering what order should things be done? How long should it take a mechanically capable person for each aspect? What say the masses who have gone this same path? Cost is not really a concern, but I also like to get the most bang for my buck... Thanks!
 
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Race Tech would be a good place to start, they will assist you over the phone in helping determine what products will help you achieve your goals.
In the front end, you most likely will want to install new emulators, springs, seals and the proper oil weight all working together to give you the ride of your dreams. They can also rebuild your rear shock for that specific ride you desire. There is not much to the mechanical side of this, but there is some science to getting all the components and oil weight dialed in to get the correct response. Having the front forks and the rear shock working together is key... There are several suspension companies that can help you out, race tech is just one. Traxxion Dynamics is top notch, but they are a little spendy.
Hope this helps.
 
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I too noticed the suspension seemed wrong when I got my ST1300. I have done a small inexpensive mod that made a HUGE difference so you might want to go cheap and just see how much of an improvement what I did makes. The stock springs on the front end are junk (remove and discard) I installed sonic springs which cost me less than $100 (call sonic and inquire) the replacement is easy to do and besides you need to replace the fork fluid periodically (google replacing fork fluid) very important to change fork fluid @10,000 miles. That will take care of the front. Google replacing rear shock preload fluid and then do that. The ST1300 rear shock is a pretty good shock BUT it must be adjusted correctly for height and damping, after replacing shock pre-load fluid (with fork oil) adjust the height and damping in accordance with the owners manual. You can tweek in small increments after adjusting to spec.
OR if you just have money to burn then skip all I said and go with about $1500 worth of suspension mods.
 

T_C

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I did the Sonic Springs on the front and while in there cleaned/changed the fork oil. Huge improvement! Need to probably be flushing the fork oil once ate least every other year anyway. Right around $100 with springs, new spacers cut to length and different weight of oil. Total time to change, clean and fill, one afternoon.

Rear shock I was just going to upgrade the spring for the time being, next biggest bang for the buck on a stock ST.
I was looking at RaceTech, they had a representative in the area, but the factory representative just had to give me his opinion and information about me be a darkside type of bike. And it wasn't asked for or anything I needed to hear (again).

So I'll be looking to Penske for the rear spring. Probably do that this winter.
 
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Outbackwack

Outbackwack

Howard
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'13 Vstrom 650
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MCL fork brace just ordered as well... What weight of fork oil you running? 5W? Sonic calculated my spring weight at 1.2
 
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dduelin

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This is what I did at about 100K ago and I've been very happy with the bike since. I weigh about 175 geared up, never ride two up, and travel with usually 60 lbs or less of camping gear. I ride in a sporting manner.

The stock sag on the fork was something like 47 mm. I fiddled with cutting spacers to get the sag to 36 mm with the stock springs which I like and still use. My bike and I needed an extra 16mm of spacer length to hit my target of 36mm. I change the fork oil about every 15 or 20,000 miles and always check the spring free length and the springs are within a mm or 2 of original length after 8 years and 140,000 miles, well within Honda's specs for free length. Lots of people junk the stock springs but if you are a light rider under 160 lbs the spring rate is in the ball park of all the tuning guides and the springs will last forever. Static sag and rider sag numbers document choice of spring rate. Race Tech's spring rate calculator tells me to use a fork spring rate of .867 kg/mm and the stock spring is .86 kg/mm. I left the stock ones in. Race Tech uses straight rate springs and the stock one is wound progressively so the first part of my bike's fork travel is a little softer than RT springs. I blend my own fork oil with 2:1 ratio of Honda 5wt and 10wt oils. the stock fork is over damped and lightening the oil sped up the compression and rebound damping. It works well for me....I would like a little more rebound damping but without revalving the forks with Race Tech's Gold valves the rebound damping is still good enough for me. I have essentially no cost in the forks - just my time and a few bucks in PVC spacers.

I had Race Tech build a stock Honda rear shock with RT valving and kept the stock spring. Again, the free sag and rider sag numbers are good under my weight. I can use the stock preload adjuster to set sag to match the fork sag and have a lot left over for the occasional two up ride so I never swapped the spring. The RT rebuild shock met my needs for about $400. The bike has a soft ride on smooth pavement, a taut ride over bumpy surfaces and feels good in the corners. The stock suspension wallowed deeply in corners and was uncontrolled in fast repetitive transitions.

Good luck, you will get many differing replies to make sense of...I can only speak for myself and what worked for me.

Edit: At 72K I replaced all bushings and seals in the forks but they really didn't need it. Changing the fork oil often kept bushing and fork tube wear to the minimum. I'm at double that now with everything still working smooth and without noise or weeps, seeps, or leaks. 96K I replaced the steering head bearings with tapered bearings.
 
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dduelin

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MCL fork brace just ordered as well... What weight of fork oil you running? 5W? Sonic calculated my spring weight at 1.2
Sonic's calculator recommends 1.2 from something like 115 lbs to close to and including gigantic. Kind of makes you wonder.
 
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Outbackwack

Outbackwack

Howard
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Sonic's calculator recommends 1.2 from something like 115 lbs to close to and including gigantic. Kind of makes you wonder.
Yeah, I played with some numbers and got the same 1.2 as well... kinda fishy me thinks...
 
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MCL fork brace just ordered as well... What weight of fork oil you running? 5W? Sonic calculated my spring weight at 1.2
I originally tried a lighter wt fluid but found the BellRay 10 wt best for me (stock Honda valving). If 1.2 is what Sonic suggest that is what I would go with, in fact 1.2 is what I used as well. I also replaced my steering head bearing with tapered roller bearings when I had my front end apart--really did not need too but tapered bearings are stronger and perform better if installed and torqued correctly (not much torque once seated)
 
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CruSTy

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++1 on Sonic front springs and the rear pre-load adjuster fluid. Also added the MCL Fork brace. Totally different bike now.

I too noticed the suspension seemed wrong when I got my ST1300. I have done a small inexpensive mod that made a HUGE difference so you might want to go cheap and just see how much of an improvement what I did makes. The stock springs on the front end are junk (remove and discard) I installed sonic springs which cost me less than $100 (call sonic and inquire) the replacement is easy to do and besides you need to replace the fork fluid periodically (google replacing fork fluid) very important to change fork fluid @10,000 miles. That will take care of the front. Google replacing rear shock preload fluid and then do that. The ST1300 rear shock is a pretty good shock BUT it must be adjusted correctly for height and damping, after replacing shock pre-load fluid (with fork oil) adjust the height and damping in accordance with the owners manual. You can tweek in small increments after adjusting to spec.
OR if you just have money to burn then skip all I said and go with about $1500 worth of suspension mods.
 

mlheck

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I started out trying the 1.1 sonic spring and found the front end to stiff. Might work great on a track, but not on the roads I ride. I weight 175 with gear. When all said and done I ended up with .90 front springs, gold valves and adjustable caps on the front with a Racetech rebuilt shock and 1200# spring on the back. I can now do a decent job of keeping up with my son and his CBR.

If I hadn't spent the money on the upgrade it would most likely have been spent on a new FJR1300ES instead.
 
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Outbackwack

Outbackwack

Howard
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I started out trying the 1.1 sonic spring and found the front end to stiff. Might work great on a track, but not on the roads I ride. I weight 175 with gear. When all said and done I ended up with .90 front springs, gold valves and adjustable caps on the front with a Racetech rebuilt shock and 1200# spring on the back.
I was wondering about the Sonic spring rates. The roads around New England up here are crappy at best... lots of cracks, bumps, pot holes and frost heaves. I need something that handles well but rides nice over these crappy roads. The only way their calculator came up with 0.9 for me was to enter the bike's weight at 550, and we know THAT will never happen!
 
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I started out trying the 1.1 sonic spring and found the front end to stiff. Might work great on a track, but not on the roads I ride. I weight 175 with gear. When all said and done I ended up with .90 front springs, gold valves and adjustable caps on the front with a Racetech rebuilt shock and 1200# spring on the back. I can now do a decent job of keeping up with my son and his CBR.
I am pretty sure the guys at sonic know there springs and rates quite well----was your fluid level correct and plastic tubes cut to their specs? Their specs are for stock honda valves and fluid wt.
 
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I went with Hyper-Pro and never looked back.
Spot on and a good value.
http://hyperpro.com/en/streetbox/
those are progressive springs (which are the problem) the following was copied from Sonic about the differences:
[SIZE=+1]Straight-Rate Springs vs. Progressive Rate Springs[/SIZE]Over the last 20 years, one of the biggest changes in the aftermarket motorcycle suspension world has been the virtually complete switch from progressive rate springs to straight rate ones. I think it’s safe to say that there’s not a single reputable suspension tuner who advocates progressive springs. The question is why? What’s the problem with a progressive rate? Why are straight rate springs better?

One of the problems is that bikes, street bikes anyway, just don’t have enough travel to take advantage of progressive rates. The soft initial portion gets blown right through, leaving a limited amount of travel for the stiffer portion to deal with. This results in less compliance, less traction and a harsher ride. Another issue is damping; Damping rates, particularly rebound damping, need to be matched to the spring rate. With a progressive (i.e. variable) rate, that’s impossible. Damping is always a compromise and a progressive rate just makes the balancing act that much more difficult. Adding to the problem is that modern forks actually have 2 spring mediums, the steel coil and the air trapped inside. The air is intrinsically a highly progressive spring. Adding a progressively wound steel spring to the mix is just making a bad situation worse.
 

mlheck

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I am pretty sure the guys at sonic know there springs and rates quite well----was your fluid level correct and plastic tubes cut to their specs? Their specs are for stock honda valves and fluid wt.
I'm sure they do, but they just sell springs where Racetech does whole suspensions. Once I quit listening to everybody telling me what they thought was best and followed Racetech's suggestions everything came together. Yes all my settings were correct and I had many conversations with Sonic. The abvice I gave is based on what I tried, not what I think I know.
 
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I'm sure they do, but they just sell springs where Racetech does whole suspensions. Once I quit listening to everybody telling me what they thought was best and followed Racetech's suggestions everything came together. Yes all my settings were correct and I had many conversations with Sonic. The abvice I gave is based on what I tried, not what I think I know.
sorry they didn't get you right---they did for me.
 

CruSTy

My Perception is my reality.
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I installed Sonic 1.2 springs. I'm 230# and do a lot of 2 up riding. Over all this was the best bang for the buck. Sonic 1.1 springs would have probably worked as well. Either way moving away from the stock progressive springs made a huge difference. I'm sure there are gains to be made going with more expensive stuff but how much improvement do you need?
 
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This summer I had my suspension rebuilt/upgraded. I wrestled with why brands and how far I wanted to go. After speaking with a friend, who ride track days and is very knowledgable and experienced with suspension work and talking with Brad at KB5 Industries I decided on the RaceTech springs front and rear. He rebuilt the rear oem shock/dampener with the RaceTech rear spring. I decided I didn't need full adjustment front suspension on the ST. Brads opinion was to re-spring it properly rates springs based on my weight/bike 300lbs. The bike was under sprung by 30% on the rear and near 50% on the front according to race techs website calculator. Race tech will only rebuild the rear unit in house so you have to mail it to them. I am very happy with the suspension and the money I saved. If I was racing and doing track days with the ST regularly then maybe having adjustable valves up front would be worth it but I don't see myself taking the ST to more then 1 or 2 times just for the experience. Good luck let us know how you make out.

In regard to the rear suspension rebuild. I would have lost some adjustment on the preload if RaceTech did the work. KB5 had a custom spacer made so it naturally sites where it Gould and still allowed full adjustment.


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