Suspension rebuild time

Started by Low594, April 05, 2009, 09:43:58 AM

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Low594

I had planned to have a pro do this for me, but financially issue have made this impossible, so it is up to me.  The bike is a '95 SS900Sp with Showa full adj.

- I need to figure out what seals I need for front and rear.  Is there a decent brand of seals out there?  I am hesitant to buy any old brand from ebay and  dealer prices seem outrageous.

- It seems that there are no specialty tools required for the front end, is this true?  What about the rear shock?

- I would like to get new springs, as the bike had been tuned for a 250 lbs rider and I am 150 lbs.  Is there a spring/rider weight chart out there?

Thank you!




EEL

If its anything like my newer showas, you'll probably need a spring compressor.. you can make one using home "despot" goodies for about 5-8 bucks.

Ddan

Get the Haynes manual and/or L.T. Snyder's.  The forks are fairly straight forward, a seal dirver is also needed but you can fab something up that will work.  I think the rear shock is a bit more involved.
2000 Monster 900Sie, a few changes
1992 900 SS, currently a pile of parts.  Now running
                    flogged successfully  NHMS  12 customized.  Twice.   T3 too.   Now retired.

Ducati Monster Forum at
www.ducatimonsterforum.org

Mr Earl

Quote from: EEL on April 05, 2009, 09:46:57 AM
If its anything like my newer showas, you'll probably need a spring compressor.. you can make one using home "despot" goodies for about 5-8 bucks.

Care to elaborate?  I'd be very interested in a cheap spring tool, too  [thumbsup]

Thanks.
Leo Vince CF slip-ons, '01 SS900 fully adjustable Showa forks w/ST2 springs, rebuilt S4 shock w/Ohlins spring, 748 dog bone, Swatt clip-ons above the triple, Sargent seat, Duplicolor-Dark seat cowl, Rizoma grips, Techlusion TFI, SBK front fender, Evoluzione slave, BMC sport air filter, 14-tooth sprocket, Desmotimes caseguard, S2R side panels, Pantah belt covers, fake CRG LS mirrors, extra black zip-ties, right grip control imprint on tank, de-cannistered, Ducati Meccanica Bologna key ring

bschur13

#4
the rear shock is a piece of cake. 

I just did mine over the winter.  In the garage, on the side stand, by myself.  The only tool I had was a universal spanner wrench I picked up for 12 bucks.  I wouldnt suggest doing it alone if you dont have to but it was way easier then I expected.   I weigh 195 and used a eibach 650 spring.  you would probably want a 600, but ask more knowledgeable folks.  (search my recent posts to read informative info from more knowledgeable people on the front and rear springs. They may answer a bunch of your questions)   

I am in the same boat on the front springs and I think we have the same forks as well (01 fully adjustable showas).  I was recommended .90 springs.  If I had to guess you would need .85kg.  I hate having to pay labor when I can do it myself.  From what I read on here the front is more difficult.  The taking off part is not so hard but more of the internal stuff, like the seals.  However it seems like it should be fairly straight forward if you have front and rear stands. (or at least a way of holding the front of the bike up, I dont)  :(   You dont need a spring compressor see link  http://www.squidbusters.com/sb/showthread.php?t=7816


Low594

Thanks for the info everyone!  i went to the RaceTech site, not sure why I hadnt already gone there!  they had a lot of info like available parts and the spring rate calc, which made a calc for my weight and street riding and also told me what was the stock rates!  Next, more sleep and then research and order parts!

Ddan

Quote from: bschur13 on April 05, 2009, 09:29:20 PM
the rear shock is a piece of cake. 

I just did mine over the winter.  In the garage, on the side stand, by myself.  The only tool I had was a universal spanner wrench I picked up for 12 bucks.  I wouldnt suggest doing it alone if you dont have to but it was way easier then I expected.   I weigh 195 and used a eibach 650 spring.  you would probably want a 600, but ask more knowledgeable folks.  (search my recent posts to read informative info from more knowledgeable people on the front and rear springs. They may answer a bunch of your questions)   

I am in the same boat on the front springs and I think we have the same forks as well (01 fully adjustable showas).  I was recommended .90 springs.  If I had to guess you would need .85kg.  I hate having to pay labor when I can do it myself.  From what I read on here the front is more difficult.  The taking off part is not so hard but more of the internal stuff, like the seals.  However it seems like it should be fairly straight forward if you have front and rear stands. (or at least a way of holding the front of the bike up, I dont)  :(   You dont need a spring compressor see link  http://www.squidbusters.com/sb/showthread.php?t=7816


Changing the spring on the rear is simple.  The OP asked about seals tho, and that's a different ball game.  The front seals aren't that difficult and if you want to do your own maintenance the manuals will pay for themselves first time out.
2000 Monster 900Sie, a few changes
1992 900 SS, currently a pile of parts.  Now running
                    flogged successfully  NHMS  12 customized.  Twice.   T3 too.   Now retired.

Ducati Monster Forum at
www.ducatimonsterforum.org

Speeddog

You can get fork seals from RaceTech.
They probably have seals for the rear shock.
They also sell seal drivers for the forks.
It is possible to improvise a way to install the front seals, if you're careful.

Front springs? I'd say .80.
rear, I'd say an 8.0 or 8.5, depending on how you ride.

Dunno if the RaceTech spring calculator is good for the rear on an SS, their one for the Monster is FUBAR.

- - - - - Valley Desmo Service - - - - -
Reseda, CA

(951) 640-8908


~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

Low594

Quote from: Dan on April 06, 2009, 03:13:48 AMChanging the spring on the rear is simple.  The OP asked about seals tho, and that's a different ball game.  The front seals aren't that difficult and if you want to do your own maintenance the manuals will pay for themselves first time out.
That is correct, I need to replace the seals in the rear shock as well.  What manuals and where can they be purchased?  I plan to get the DesmoTimes book.

Quote from: Speeddog on April 06, 2009, 10:13:55 AM
You can get fork seals from RaceTech.
They probably have seals for the rear shock.
They also sell seal drivers for the forks.
It is possible to improvise a way to install the front seals, if you're careful.

Front springs? I'd say .80.
rear, I'd say an 8.0 or 8.5, depending on how you ride.

Dunno if the RaceTech spring calculator is good for the rear on an SS, their one for the Monster is FUBAR.
Here's what the RaceTech calc says,
FRONT FORK SPRINGS
Recommended Fork Spring Rate for Street: 0.806 kg/mm (use closest available)
Stock Fork Spring Rate: .650 kg/mm (stock)
REAR SHOCK SPRING
Recommended Rear Shock Spring Rate for Street: 6.88 kg/mm (use closest available)
Stock Shock Spring Rate: 8.5* kg/mm (stock)

This seems a little odd to me, a heavier than stock in the front and a lighter than stock in the rear??  From other people tuning their bikes I was under the impression that I would be looking for .80-.85 for the front, but I havent seen any info for the rear.

I ride street alot, weekends are spent in the Santa Cruz Mtns (near the infamous Alice's) riding mildly aggressive and i regularily ride large North Cali loops (3-500 miles).  The long runs pretty much kill me in the current setup, but that is too stiff and I have a bad lower back.

Speeddog

The stock front springs are likely the crapola dual-rate ones, hence the ridiculous low rate that RaceTech shows.
.80 front springs are about the softest you'll find available.

Hmmm.
Seems the Racetech calculator is FUBAR for SS too.  [roll]

There's quite a few good suspension shops in your general area.
In your situation, I'd give the rear shock to them for a rebuild.
- - - - - Valley Desmo Service - - - - -
Reseda, CA

(951) 640-8908


~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

gage

On the rear shock you could also contact DUCVET (google: clubhouse motorsports) and mail it to him.

He just did a full rebuild on mine for an extremely reasonable (Read Cheap) price. 

ducpainter

Quote from: gage on April 06, 2009, 02:50:34 PM
On the rear shock you could also contact DUCVET (google: clubhouse motorsports) and mail it to him.

He just did a full rebuild on mine for an extremely reasonable (Read Cheap) price. 
He's a sponsor here so you can pm him also.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
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bigiain

Quote from: Low594 on April 06, 2009, 12:28:15 PMFrom other people tuning their bikes I was under the impression that I would be looking for .80-.85 for the front, but I havent seen any info for the rear.

It's pretty easy to compare front spring rates across different bikes, 'cause the geometry is all pretty much the same (small differences in rake angle can be safely ignored), but you can't compare rear spring rates without taking linkage ratios into account. What other people use for spring rates on their Monster or R6 or whatever isn't directly comparable to your SS, unless you know the linkage ratios are the same...

big

ducpainter

Quote from: bigiain on April 06, 2009, 05:57:53 PM
It's pretty easy to compare front spring rates across different bikes, 'cause the geometry is all pretty much the same (small differences in rake angle can be safely ignored), but you can't compare rear spring rates without taking linkage ratios into account. What other people use for spring rates on their Monster or R6 or whatever isn't directly comparable to your SS, unless you know the linkage ratios are the same...

big
...and add the fact that the SS has no linkage it becomes even more muddled.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."



bigiain

Quote from: ducpainter on April 06, 2009, 06:16:44 PM
...and add the fact that the SS has no linkage it becomes even more muddled.

I _think_ they still refer to "linkage ratios" even when the shock is directly connected to the swingarm and frame like an SS - it's the ratio of distance moved vertically by the axle compared to distance the spring compresses, and it's rarely 1:1 except maybe for old school twin shock machines with vertically mounted shocks - even angling the shock forward changes that ratio.

It gets more complicated pretty quickly too - the old monsters with the 851 derived suspension have a "rising rate linkage", which means the linkage ratio changes throughout the suspensions travel, getting "harder" as the suspension compresses, so your "optimal" spring rate depends on your static loaded sag... I'm not sure how close to linear rates the new non-hoop suspenson Monsters are, but by eye I'd guess _reasonably_ close, as for the SS suspension, I've got no idea...

(Interesting note, although rising rate linkages were cutting edge world superbike winning technology back in the 851/888 heyday, these days MotoGP bikes use falling rate linkages - the theory being you need much more "suppleness" in the suspension when leaned over at 55 degrees or more and the vertical movement of the rear wheel becomes a much larger movement in the suspension travel direction.)

big