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Don't waste your money! Progressive fork springs don't work; the lighter spring rate for initial movement sounds like a good idea, but the damping will be too strong. If you go to lighter fork oil then the damping will be insufficient for the higher rate spring. If you want to transform your forks for the least amont of money then you need Racetech fork springs from the USA. I've done this mod to my 900 bevel and it is the best mod that I've ever done. If you do a search of this forum you will find a write up I posted with the details. If you can't find it, I can let you know the info.
 

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Believe me, it's all you need to do. OK, revalving will make them better still, but the Racetech springs make a world of difference.
 

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Discussion Starter · #6 ·
Colin do you need any special tools to fit the racetech springs? I've never done anything to forks before so I'm just wondering whether I'd need to get it done at a shop or not.
Thanks for the links morini35.
 

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You need a 12mm hex socket to undo the cap (and big arms to put it back on).

First thing is; which model do you have? Various Ducati models using Ceriani/Marzocchi forks use different length tubes eg 580/590/600 etc. So you have to know which model you have before you order.

In simple form you take the caps off and swap the springs over (without losing any oil), insert the pre load tube supplied then put the caps back on.

I think the kits for each bike are within a standard range and come with a pre cut length of PVC tubing which pre loads the spring.

Question is how much pre load will you have when you hop back on. Most people use around 30-40mm.

They easiest way to check is to put a zip tie on the forks, resting on the seal, sit on it then carefully put it on the center stand (so the forks can top out) and measure the difference.

From memory the last time I did a spring swap I had to trim the supplied PVC tubes a couple of times to get it right.

The kits do come with instructions.

The other thing you should check is the air gap i.e. the distance from the top of the stanchion to the oil level. My memory is a bit hazy but I think I was running 150mm in each leg. Measured at the tank side of the tubes and no spring. Otherwise drain all of the oil and measure by volume. I think standard was 300ml. Others will have more opinions on this and some.
 

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As Morini35 says, it's easy to fit the springs, but you will have to check the preload once they are fitted. The best bet for this is to look at an on-line tutorial, of which there are many. The spacers supplied were perfect for me, so no alterations were necessary. I would change the damping fluid to SAE 20 too as the forks will be much more compliant and most of the standard damping is from the springs scraping against the fork tubes!
 

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Discussion Starter · #9 ·
Thanks for the advice guys I appreciate it , morini35 the bike is a 1982 900ss, knowing me it will be weeks before I get around to it but I'll let you know how I go when the time comes, cheers
 

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and most of the standard damping is from the springs scraping against the fork tubes!
and to think that we once thought Ducati, Laverda, MV, Moto Guzzi and Morini riders were riding the cutting edge of suspension technology. Ha

I'll never forget riding a friends brand new 1985 GPZ900R and being totally humbled ( read jealous) by how well it handled.
 

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I guess that the reason old Italian and British bikes handled well for their time was due to strong frames and hard suspension (and gritted teeth). The early Jap bikes tried to provide comfort, but very little damping to go with it. They soon learned (the Japanese are no mugs).
 

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any linear rate spring the right diameter should be fine. you'd probably want an 0.8 or 0.85 at a guess. you could probably cut the original springs down too and make new preload tubes the right length. i did some springs in some mv forks a couple of years ago, cut them in half pretty much.

the repsol 15w30 fork oil seems to work well in the oldies. or get some of glyn's sports valves if you really want to get carried away.
 

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Discussion Starter · #13 · (Edited)
Thanks again for the advice. Before I go to the suspension I have a bigger problem to sort first though.

Does anyone know much about the Silent Hektik ignition system (or ignition systems in general). I recently had one of these installed on my bike and the driveline snatch or backlash when rolling on and off throttle is much worse than before (before being hardly noticeable) now it is bad enough it's a real chore to ride.

I don't know anything about ignition systems, advances and curves, however i have read that this system has 16 possible ignition advance curves. Is it possible the curve it is set on is causing this (like a harsher instantaneous throttle response) and another position could remedy it?
 

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Probably from Gowanloch's in Sydney? Ask them for advice on the settings or Google what other users have tried.

You're from Brisbane so who installed it? If I was going to use any one I'd use Bevan at Euro Twins. He's by far the most respected Ducati mechanic, both belt or bevel, in Brisbane.

https://www.eurotwins.com.au/
 

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It sounds like the ignition curve is way too fierce; is there an easy way to swap between the curves?
 

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I think 16 ways. A mate's brother runs one in his race bike (single) and reckons he started at 1 then tried 16 and worked his way back. He uses click # 4.
 

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Discussion Starter · #17 ·
I think 16 ways. A mate's brother runs one in his race bike (single) and reckons he started at 1 then tried 16 and worked his way back. He uses click # 4.
morini35 do you know if your mates brothers bike displayed the symtoms I described (backlash) on any of those settings that he tried before settling on no. 4
 

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We were out cycling, discussing this and the world's problems on the weekend and I think he said his brother has similar issues. I'll get him to check.
 
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