900SS Ie Sport with non adjustable forks - Page 2 - Ducati.ms - The Ultimate Ducati Forum
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post #11 of 17 (permalink) Old May 1st, 2019, 7:52 am
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I assume youíre sure the forks donít leak. If they are Marzocchi, you can stiffen damping using ATF. If youíre under 80 kilos or just trying to fill with something equivalent to stock, try 7 1/2 w . If youíre a lighter rider or you donít feel like spending for new springs, it will help a lot to use spacers to get your sag in the ballpark. I use pvc because itís cheap, and easy to work with. Some say use conduit or some type thin wall tubing because the pvc takes up space. I say on these forks that is probably not a bad thing to reduce air volume to reduce bottoming out. At 87 kilos I used ATF and quite a bit of pvc to get sag on the low side, so they were a bit stiff but definitely a big improvement for little money.

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post #12 of 17 (permalink) Old May 1st, 2019, 8:48 am
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he needs to look at the springs and fix whatever issue is there, then set the oil height to a level suitable for the chosen spring rate. if he fixates on a number in a manual then he's probably not going to get the result he wants.
I couldn't agree with you more, but some people simply believe that Ducati knows best and changing to what a couple of nut jobs on the internet tell them to do is not wise. You and I may have done this a few thousand times but it is the comfort of knowing that Ducati engineers are way smarter than us and wouldn't it be heresy? I have had conversations in the past on why changing a one size fits all spring for a spring tailored to a riders weight/preference is superior, it matters not if the owner is not willing to take that leap.

Oem is at least safe and you should get oem results, no better or worse than the bike rolled off the showroom floor and if that works for you ....
If the forks were not done properly then the improvement before this owner got them than could be just what is desired. If you are used to riding vintage damper rod forks this should still be better. Paul Thede (sp) owner or race tech once said " the best you know is the best you have ridden" so by that rule if you only ride less than good your expectations are low enough most will be acceptable.

I also do not know the forks he has based on the year listed did not come to the USA so what forks were mounted could be different than what I have played with. I would guess they are Marrzzocci not showas based on the age but only a photo would prove that. Sounds like a base model 800ss we got and 5wt was what I used in them.
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post #13 of 17 (permalink) Old May 1st, 2019, 12:23 pm Thread Starter
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Many Thanks for your words of wisdom guys.

After numerous calls to Ducati dealers and poking about it would appear the Base Line oil levels for my bike ( 900 Sport - Marzocchis - non adjustable) is 108mm. Drained out as I said approx 380ish cc and refilled with 490cc as this is where the oil levels settles. Procedure is half fill, expel air from cartridge by pumping up and down , install large diameter plastic spacer, another plastic spacer + spring. Fix collet, lock 4 sided nut against top cap and screw into top slider. Install back into bike and test this evening.

Just finished and now of jacks and straight away - the bike ... forks feel completely different. There is more resistance to pumping so the suspension feels as though its doing something rather than nothing

As to my knowledge of suspension systems ....limited with bikes but BSc Hons, MSc, coded welder and 20 odd years building 3.5 - 5.0 litre V8 road and competition engines.

Own four cars including a supercharged V8 and twin turbo V8 and a a flat six. My years as a mature student studying taught me that I knew pretty much jack shit ( very humbling) but proved I was able to learn and apply.

I prefer to know how things work as this helps with fault finding.

I now have a base setting and whether this is right or wrong I will find out and modify accordingly to suit my weight/mass and riding style.

Keep you posted of my findings as no doubt there will need to be mods carried out.
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post #14 of 17 (permalink) Old May 1st, 2019, 1:24 pm Thread Starter
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Brief ride out this evening on Norfolk roads and surfaces are worse than bad. Shocking would be a better description...

Where previously I had 100 mm of fork travel I now have 70mm. No high speed stuff but 50/60 mph and the bike feels much much better. Far from perfect but not getting the "half hand stand" under moderate braking and easier to position and place for slow corners/roundabouts.

Static sag 15 - 20mm and my weight about 14 St 7 lbs.

Reasonably happy with the result so far but will need work to make the suspension more compliant. Forks had never been apart before so factory oil levels were way way off.
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post #15 of 17 (permalink) Old May 1st, 2019, 2:01 pm
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Hey it happens I have had more than one set of forks show up to my show with not a drop of oil in them. A customer who built his own mv agusta f3 last year was complaining of fork dive on his first outing, you guessed it the shop who sold him the "race chassis" had neglected to tell him they had drained the oil in the forks for some reason. live and learn.
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post #16 of 17 (permalink) Old May 1st, 2019, 6:12 pm
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Trust No One.

'96 Ducati SS900CR, '07 S4RS, '06 Busa, '77 Bonny,
'00 Superglide, '85 Sportster, '78 SR500
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post #17 of 17 (permalink) Old May 2nd, 2019, 9:34 am Thread Starter
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Zero fork oil .......thats more than incompetent and with life and limb components, checks and double checks should always be performed. Building engines makes you like this otherwise the old night time/after work ......did I torque tat bolt, stud etc etc

Indeed trust no one or suffer the consequences. I say this through experience.....short story

Bought an old Honda 750KZ years ago .......ex dispatch riders bike with high miles . Bike looked a bit scruffy but £400 was a cheap purchase. Checked it over (mostly) - all okay, done the deal and rode it back home. Hit 90 - 100 MPH on some stretches and seemed okay.

New purchase safely home - jobs to do .......

Up on centre stand - chain a bit loose.

Process of adjusting chain tension and bearing in mind a factory endless chain .....some half witted fuck wit had only split the chain and installed a spring link. Since these chains have "o"rings hadnt managed to nip it up to install the outer clip....a chain waiting to fall off or worse......

So Brothers .....the sermon for the day has ended.

Dont want to ruin the fun but anyone else has similar stories a bit of anecdotal can help preserve life ....
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