Suspension question - new 919 owner - Wrist Twisters
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post #1 of 88 Old 06-24-2010, 07:15 PM Thread Starter
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Suspension question - new 919 owner

Hi All,

I'm a relatively new 919 owner. My bike only has about 200 miles on it. 2007 model year with fully adjustable suspension.

When riding, it seems like the stock settings are too stiff for me. When I hit bumps it bounces me off my seat. Literally up into the air.

I am 5'6" and weight about 160 pounds. Is this how the bike is supposed to be? Coming from a honda magna (cruiser) the bike feels very stiff.

All my riding is around town and I dont ride on the track. I'd like it to be a little softer so it can absorb bumps and not throw into the air everytime.

Any advice on suspension settings? Honestly, I dont fully understand what the diff settings do. Rebound, dampening, pre-load, etc....

Thanks all. This forum has been a wealth of knowledge for me. I wish I knew about it sooner!

Thanks again

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post #2 of 88 Old 06-24-2010, 07:27 PM
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The rear shock on the 919 is known for being harsh on sharp bumps. But make sure it's adjusted optimally for you before deciding to upgrade.

Basically, you want to set the sag which is how much the suspension compresses with you on the bike. You should be able to find a thread here that explains some details on it. It might be in the helpful topics for 919 owners.

After you set the sag, playing with the rebound damping might help somewhat.

Most people are pretty satisfied with the front but you might be on the light side for stock springs. Someone else can chime in on that. I had to go a bit stiffer up front (always fun ) but I weigh about 205 with gear on.

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post #3 of 88 Old 06-24-2010, 11:07 PM
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I was interested in the answer myself and found this thread:
https://wristtwisters.com/motorcycle-...ion-setup.html

Later, Guy

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post #4 of 88 Old 06-24-2010, 11:28 PM
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for the front i found that adding an extra 20-25mm of fork oil stiffened em up just the right ammount for my 165lbs.

The rear is always going to be too stiff if you run the stock spring as its sprung for about a 200lb rider. You could try loosening the preload some but that will only help a little..

I have just gotten ust to the semi harsh rear.

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post #5 of 88 Old 06-24-2010, 11:31 PM
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Several posts on this subject. You can adjust the stock unit as much as you want. Unless your roads are silky smooth, it will NEVER perform satisfactorily. Never.

I almost sold the bike because I hated the rear shock so bad...actually, "shock" is the correct terminology for the piece of trash on the 919. I bought a used Ohlins. It is fantastic. If I totalled the bike and lost the Ohlins, I'd buy this bike again and buy another Ohlins....used or new...the price is worth the upgrade.

I have connections with a local company that developed Paris-Dakar racing suspensions, and now are doing motorcycle suspensions. The head engineer holds the original patent from the 1970's, when he developed the linked monoshock first found on Suzuki's. In case you haven't noticed, that system became fairly popular...to say the least.

While they COULD make a damper unit for the 919, it just doesn't make business sense. Not enough people wanting to upgrade this bike. Those guys rode mine with the Ohlins, and were very complimentary of it's performance. That speaks volumes, as I'm just an everyday rider that THINKS the Ohlins feels good. These guys do this for a living, and their opinion holds much more weight than mine.

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post #6 of 88 Old 06-24-2010, 11:52 PM
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Quote:
Originally Posted by nd4spdbh View Post
for the front i found that adding an extra 20-25mm of fork oil stiffened em up just the right ammount for my 165lbs.
I'm sorry but this is absolutely incorrect statement.
As in any suspension system, spring rate is the #1 parameter. It needs to match an average given load. Spring is what holds a load of your bike. You need proper spring rate to achieve proper suspension sag in order to set up your suspension for it's max performance.

the oil height /valves are the to control spring when conditions are changing: braking, road surface/turns etc and excessive levels can make your forks harsher due to limiting its travel under when condition changes. Therefore it can be very counter productive as one should desire to use all of his available suspension travel
Oil height is no way affects your spring rate.

here is some good info if you are interested:

Peter Verdone Designs - Oil Height

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post #7 of 88 Old 06-25-2010, 02:19 AM
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Zaq and Blackheart are your guys on this subject. I sold my Ohlins to Blackheart, so I too have ridden a properly set up 919.

Like you, my ass was flying off the seat. I think Zaq has a guy that will respring the rear shock for you. Cost's about $125, worth a million.

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post #8 of 88 Old 06-25-2010, 07:03 AM
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The comments on the rear spring being way too stiff are true and correct for the early 919s but not so for the later ones. I'm not sure when they switched (guessing '04?) but the '07 in the original post does not have the super stiff spring like the early ones had.

Even at your light weight, the rear spring is probably O.K. You might have to go with minimum preload though. The stock preload setting is centered, I think. And the later 919s did not come with a tool kit so no tool to change it (STUPID!). You might want to invest in the tool kit. If you do much work yourself, you'll at least want the spark plug wrench.

That said, the biggest issue with all 919 rear shocks is compression damping - too stiff. But if you have your spring preload cranked too high it will aggravate the problem.

At least adjust it optimally within the limits of the stock suspension before you decide how much you hate it

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post #9 of 88 Old 06-25-2010, 07:26 AM
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Quote:
Originally Posted by catonsvilleguy View Post
That said, the biggest issue with all 919 rear shocks is compression damping - too stiff. But if you have your spring preload cranked too high it will aggravate the problem.

At least adjust it optimally within the limits of the stock suspension before you decide how much you hate it
Mine is an 07. I weigh in at 185. Compression damping is WAY TOO stiff, the spring was just too stiff.

The last statement is very true...it depends upon what you expect the bike to be able to do, and the conditions under which you operate it. After all, the stock damper unit does ride smoother than a hard-tail bike. Other than that, it is, without a doubt, the worst functioning stock rear suspension I've ever had the displeasure to ride. It's now very compliant without a tendency to bottom out or wallow excessively on exits from turns on non-perfect pavement during hard-throttle. Obviously, I haven't ridden on full-out racing bikes...I'm sure many of those could put the Ohlins-equipped 919 to the curb. Just as obviously to the racers, I'm not a racer (to them the 919 will always tend to wobble on hard exits...it's just not a stiff-enough swingarm/chassis).

Again, it depends upon the expectations of the rider, and the conditions under which they ride. It's perfectly acceptable for someone to say "it seems fine", while others loathe it. I will say that if someone thinks they like the stock unit, they'll change their mind instantly once they experience a decent-functioning damper unit on this bike.

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post #10 of 88 Old 06-25-2010, 09:53 AM
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Listen to Blackheart. He's the voice of experence. (he saves me a lot of typing)

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post #11 of 88 Old 06-25-2010, 10:09 AM
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Quote:
Originally Posted by zaq123 View Post
I'm sorry but this is absolutely incorrect statement.
As in any suspension system, spring rate is the #1 parameter. It needs to match an average given load. Spring is what holds a load of your bike. You need proper spring rate to achieve proper suspension sag in order to set up your suspension for it's max performance.

the oil height /valves are the to control spring when conditions are changing: braking, road surface/turns etc and excessive levels can make your forks harsher due to limiting its travel under when condition changes. Therefore it can be very counter productive as one should desire to use all of his available suspension travel
Oil height is no way affects your spring rate.

here is some good info if you are interested:

Peter Verdone Designs - Oil Height
belive me i know... but with a rider so close to the spring rate... the extra oil helps out just the right amount.

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post #12 of 88 Old 06-25-2010, 10:18 AM
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Gain weight, it will soften the suspension........

I weigh 260, so I really tax the suspension, but it rides silky smooth.

But what do I know, I came from riding a Softail and there is NOTHING soft about a Softail.

I Can and will ride anything!
Bikes I own:
New addition 1978 CB750Four
2006 919
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Early 1984 Ironhead Sporty (Wife has laid claim to this bike)
1986 Sporty that I am putting a ironhead engine into
YEA BIGDAA I Gotta GUN!
It's not that I am punishing YOU, I am just taking YOUR money and giving it to LAZY Asses who refuse to get off the TIT of the Government...Obama to Joe the Plumber
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post #13 of 88 Old 06-25-2010, 11:18 AM
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Quote:
Originally Posted by Blackheart View Post
Mine is an 07. I weigh in at 185. Compression damping is WAY TOO stiff, the spring was just too stiff.
Hmmmmmm. I also have an '07. And I also weigh about 185. To get the sag right with my gear on and a small tail bag, I had to set the preload at the maximum on the rear shock. So the spring was no way too stiff. If anything, it was on the soft side.

Did you ever actually set the sag? Or are you just talking about the way it felt? It felt stiff - agreed. But the spring had nothing to do with it. On the early ones it was another matter entirely.

I also switched to an Ohlins after adjusting the suspension optimally and deciding my old F'd up back could not take the stock shock long term.

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post #14 of 88 Old 06-25-2010, 02:16 PM
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Quote:
Originally Posted by zaq123 View Post
Oil height is no way affects your spring rate.

That's not entirely accurate.... The spring rate doesn't change obviously in the same way that changing your gearing doesn't change the horsepower of your bike.

What does happen though is more oil means less volume of air inside the fork tube. Liquid does not compress, but air does so it will affect the way the fork works quite drastically as less air means less room for the fork to compress overall.

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post #15 of 88 Old 06-25-2010, 02:27 PM
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Quote:
Originally Posted by catonsvilleguy View Post
Hmmmmmm. I also have an '07. And I also weigh about 185. To get the sag right with my gear on and a small tail bag, I had to set the preload at the maximum on the rear shock. So the spring was no way too stiff. If anything, it was on the soft side.

Did you ever actually set the sag? Or are you just talking about the way it felt? It felt stiff - agreed. But the spring had nothing to do with it. On the early ones it was another matter entirely.

I also switched to an Ohlins after adjusting the suspension optimally and deciding my old F'd up back could not take the stock shock long term.
Yep, I set the sag...had to go to near minimum on the preload. Makes me suspect poor quality control on the spring rates to have that much variability from yours to mine, being as how we weigh the same. Of course, there is the variable of your eyeballs and mine, so, there's no way to know, without a doubt, that there was that much difference in your spring compared to mine.

Just to make sure I'm clear: I am NOT qualified to be a suspension expert, nor do I want to appear to be trying to impersonate one. I'm just a rider with an opinion based upon what I've ridden, and how the bike reacts under my piloting.

Stick with LordDuckhunter, and his ilk, for your suspension decisions...they know more about this stuff than I ever will.

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post #16 of 88 Old 06-25-2010, 02:35 PM
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Quote:
Originally Posted by Lord Duckhunter View Post
That's not entirely accurate.... The spring rate doesn't change obviously in the same way that changing your gearing doesn't change the horsepower of your bike.

What does happen though is more oil means less volume of air inside the fork tube. Liquid does not compress, but air does so it will affect the way the fork works quite drastically as less air means less room for the fork to compress overall.
yup... like i said the 1. change to good quality 10w fork oil + the addition of 25mm of fluid. made the front feel much more planted... also it raised my sag slightly as the "air spring" in the fork is now on a slightly stiffer curve.

As far as the rear.... im still in search for a cheap replacement... but that aint ever gonna happen.

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post #17 of 88 Old 06-25-2010, 02:58 PM
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post #18 of 88 Old 06-25-2010, 03:09 PM
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too bad theres no way for you to set up a "first one's free" LDH.
you'd have us like crackheads.

nice moto-porn.
maybe my street bike will deserve one someday.

is this a battle of wills, to see how long you'll keep 8 Hornet shocks on the shelves before you feel it's appropriate to clear them out?

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post #19 of 88 Old 06-25-2010, 03:11 PM
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Yea they don't move very quickly... About one every two months.

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post #20 of 88 Old 06-25-2010, 03:15 PM
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alls i see there is a pay check or 2 on a shock.... how much those thing run? I would love to have one but dont think i could justify the price haha.

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post #21 of 88 Old 06-25-2010, 03:18 PM
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Quote:
Originally Posted by Lord Duckhunter View Post
Yea they don't move very quickly... About one every two months.
And THAT is why the local racing shock company isn't going to build any for this bike.

I LOVE what the Ohlins does for the 919...the Ohlins saved me thousands of dollars I would have lost by selling the 919 and buying another bike. That would have been a pity...because it's a fine machine with a decently functioning damper under it!

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post #22 of 88 Old 06-25-2010, 03:21 PM
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Originally Posted by nd4spdbh View Post
alls i see there is a pay check or 2 on a shock.... how much those thing run? I would love to have one but dont think i could justify the price haha.

I've been selling them for $919 Shipped, but I will let the one in the busted up box go for $850 plus shipping

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post #23 of 88 Old 06-25-2010, 03:24 PM
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what complex technical algorhythms did you use to come up with that original retail price?

do you have some Ducati shocks for $916 and $999, model-dependant?


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post #24 of 88 Old 06-25-2010, 03:28 PM
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what complex technical algorhythms did you use to come up with that original retail price?

do you have some Ducati shocks for $916 and $999, model-dependant?


Actually I could probably do that

Last I heard though there was only 1 DU301 shock left in the world for the 749/999

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post #25 of 88 Old 06-25-2010, 04:18 PM
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What's the general concensus for springs in the front?

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post #26 of 88 Old 06-25-2010, 04:54 PM
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Quote:
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What's the general concensus for springs in the front?
they are sprung for about a 140lb rider... aka they are too soft for most. BUT like i said 25mm of extra fork oil over the standard height... and good quality fork oil remedied the situation for me at 160lbs. Its not the best way to go about it but its much MUCH cheaper than buying springs.

If you weigh much more than 165ish... then new springs are kinda necessary if you plan to get the most outta the bike.

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post #27 of 88 Old 06-25-2010, 05:01 PM
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I've heard Racetech(sp) mentioned alot, what other brands of springs are we using for the 919's? BTW, I'm probably around 230 with gear and have Givi side cases and top case.

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post #28 of 88 Old 06-25-2010, 06:07 PM
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Quote:
Originally Posted by Blackheart View Post
Of course, there is the variable of your eyeballs and mine, so, there's no way to know, without a doubt, that there was that much difference in your spring compared to mine.
No eyeballs involved. I put a piece of tape on my left can directly above the axle and had my son measure with a tape measure. No guesswork in my shop!

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post #29 of 88 Old 06-25-2010, 06:33 PM
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Quote:
Originally Posted by nd4spdbh View Post
they are sprung for about a 140lb rider... aka they are too soft for most.
Actually they are sprung for riding with a passenger... The extra weight on the back of the bike lessens the load on the front so lighter springs offer a better ride at normal cruising speeds.

At any rate (no pun intended) I used the stock forks to run laps around Barber that would have put me on any WERA grid. As long as you are smooth with your inputs the stock stuff isn't too bad and the idea of "getting the most" out of this bike always makes me laugh. As I have said many times before the super flexy chassis & swingarm are the weakest links in the 919 and all the suspension in the world is not going to transform this bike into an R-type sportbike. It just isn't going to happen. The best you can hope for is making the ride a little bit smoother and more compliant in regards to comfort.

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post #30 of 88 Old 06-25-2010, 07:16 PM
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Quote:
Originally Posted by Lord Duckhunter View Post
Actually they are sprung for riding with a passenger... The extra weight on the back of the bike lessens the load on the front so lighter springs offer a better ride at normal cruising speeds.

At any rate (no pun intended) I used the stock forks to run laps around Barber that would have put me on any WERA grid. As long as you are smooth with your inputs the stock stuff isn't too bad and the idea of "getting the most" out of this bike always makes me laugh. As I have said many times before the super flexy chassis & swingarm are the weakest links in the 919 and all the suspension in the world is not going to transform this bike into an R-type sportbike. It just isn't going to happen. The best you can hope for is making the ride a little bit smoother and more compliant in regards to comfort.
ahh... that makes sense why the suspension is setup the way it is... stiff in the back soft in the front.

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post #31 of 88 Old 06-25-2010, 10:56 PM
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Quote:
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No eyeballs involved. I put a piece of tape on my left can directly above the axle and had my son measure with a tape measure. No guesswork in my shop!
I used a measured grid taped on the bike, a laser, and a mirror....easy to do and don't need help.

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post #32 of 88 Old 06-26-2010, 02:16 AM
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I don't think anyone ever buys a 919 with the intention of beating up on RR types.

People buy 919s for the enjoyment of a comfy all purpose street bike. An Ohlins/919 is a way more enjoyable bike than a box stock 919.

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post #33 of 88 Old 06-26-2010, 06:46 AM
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Quote:
Originally Posted by Lord Duckhunter View Post
That's not entirely accurate.... The spring rate doesn't change obviously in the same way that changing your gearing doesn't change the horsepower of your bike.

What does happen though is more oil means less volume of air inside the fork tube. Liquid does not compress, but air does so it will affect the way the fork works quite drastically as less air means less room for the fork to compress overall.
oil does not affect a spring rate, spring rate depends 100% on the steel properties its made out off.

if you are talking about fork damping when you say "spring rate"??, than yes, oil height affects damping abilities, obviously

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post #34 of 88 Old 06-26-2010, 10:11 AM
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Quote:
Originally Posted by zaq123 View Post
oil does not affect a spring rate, spring rate depends 100% on the steel properties its made out off.

if you are talking about fork damping when you say "spring rate"??, than yes, oil height affects damping abilities, obviously
theres a progressive air spring in the 919 forks. when the fork compresses the air in the top of the fork it exerts a force just like a spring.... the less ammount of air there is for the fork to compress the stiffer the air spring will be.

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post #35 of 88 Old 06-26-2010, 11:08 AM
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Quote:
Originally Posted by nd4spdbh View Post
theres a progressive air spring in the 919 forks. when the fork compresses the air in the top of the fork it exerts a force just like a spring.... the less ammount of air there is for the fork to compress the stiffer the air spring will be.
Absolutely correct. In fact, all forks that are not vented have this feature.

It's basically an air spring that exerts no force until the fork starts to compress. As the volume of air above the oil decreases with fork compression, the force of the air spring increases. The force of the air spring at full compression can be adjusted by adjusting the level of the fork oil. More oil = less air = higher air spring rate.

Any book on motorcycle suspension discusses this basic concept. Anyone who argues this is not true might benefit from some easy reading on motorcycle suspensions.

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post #36 of 88 Old 06-26-2010, 12:20 PM Thread Starter
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Good stuff here. So for me (5' 6" weigh 160), should i start by only adjusting my preload?

Any suggested settings I should try? I really dont know where to begin with the adjustments.

Thanks again all!

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post #37 of 88 Old 06-26-2010, 12:39 PM
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Quote:
Originally Posted by jbanke1 View Post
Good stuff here. So for me (5' 6" weigh 160), should i start by only adjusting my preload?

Any suggested settings I should try? I really dont know where to begin with the adjustments.

Thanks again all!
i run my fronts with 25mm of extra fork oil... but i refilled them all with good 10w maxima stuff... preload on the 3rd notch and rebound halfway between halfway on the soft side.

As far as the rear... run mid way on preload and havnt rly payed with the rebound.

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post #38 of 88 Old 06-26-2010, 02:16 PM
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Agree with bucky. Nice porn. never do I have the money.

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post #39 of 88 Old 06-26-2010, 02:37 PM
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Quote:
Originally Posted by nd4spdbh View Post
for the front i found that adding an extra 20-25mm of fork oil stiffened em up just the right ammount for my 165lbs.
Despite what anyone else may say, I have used fork oil level to fine tune the fork spring rate. Remember PV=nRT, part of the Ideal Gas Law, which gives the pressure increase of a gas in a variable volume container. At the stock height setting the air spring value adds 27 pounds (gauge) to the spring rate at full stroke. Adding one inch to the oil height bumps this value to 32.3 pounds, and adding two inches takes it to 40.2 pounds. As gas pressure rise is exponential the greatest effect is near the end of the stroke.

There is a downside to this -- as the air pressure rises the fork seal lips have considerably more pressure against them, causing inconsistent fork action through the last 1/3 of the stroke due to increased seal lip pressure against the stantion tube surface (friction). It can have a significant effect on compliance if you go overboard with this.

There is a way to increase the rate of a spring: shorten it and add a longer spacer to compensate. Removing coils increases the rate by simply increasing the load on each coil remaining. It must be done properly by creating a new "dead" (shorted) coil at the cut end and grinding it absolutely flat, otherwise the spring will bend as it compresses. Also, be careful when doing this as removing too many coils can cause the spring to coil bind before topping out, sending loads on the fork cap and upper surface of the damper through the roof, usually breaking something.

There are physical limits built into any fork assembly which define the travel available, and unless you grossly overfill the forks the travel limitation stays with the hard parts. Damping rates, however, do not significantly change with pressure in the system -- oil moves through an orifice at a relatively fixed rate regardless of the pressure, and as long as the entire damper is immersed in oil at full extension the damping rate will not change over the full stroke. One variable introduced is while the damping rates do not change with pressure raising the oil level increases the effective spring rate, so some tweaking of the dampers will be necessary to compensate for this.

My recommendation? As several have already said set your sag properly, then fiddle with the damper adjustments until it feels right. Past that you're talking $919 plus shipping for a better rear shock (I don't remember where I heard that), proper springs for both ends, and a lot of time and meticulous note taking getting it all dialed in properly.

Good luck.

Rob

If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
------- Rob --------
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post #40 of 88 Old 06-26-2010, 07:14 PM
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Quote:
Originally Posted by Sniper View Post
Listen to Blackheart. He's the voice of experence. (he saves me a lot of typing)
+1 /lol

I too have Ohlins rear, plus RaceTech internals up front. It made a huge difference. And he's right about the frame/chassis, but even as such, the upgraded suspension is well worth the investment. It'll never perform like a SS bike, but it was never intended to be one in the first place. Any upgrade for this bike is well worth it, and it need not be Ohlins either; however, if you have the money, then go for it. When you do upgrade the componants, you will still need to get it set-up properly. Some bike shops will charge $25-$30 to set it up (here in Houston). I get mine done at the trackdays, where they usually have Suspension/Tire Vendors setting up shop to provide these type of services.

Sometimes, the tires you slap on affect your suspension. I swapped out my Michelins last month to Pirelli Rosso Corsas, and the bike felt completely different and the feedback felt vague. Stuck like glue, though! And the turn-in was awesome, but I still had to reset my suspension, and it helped take care of those issues.

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