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Discussion Starter · #1 ·
I tore into the forks today to do a fluid change. I have always thought they were a bit harsh so I went with 5wt fluid instead of the book spec 7.5. I removed 20oz of fluid from each leg which was about 85mm of air with just the spring removed (sliver shim and black spring spacers in the oil). The book spec is .48 cu.dr of fluid which is 16oz and 104mm gap from the top. So whats going on here, are factory levels all over the place or did the previous owner add in more oil? I have the forks set with the same 20oz right now so will I be ok or has that been my harsh front fork cause all along.
 

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what do you mean with "harsh?"

do you mean stiff? Because stock 1100S forks aren't stiff at all. Also, you can't compare fork oils from different manufacturers 1:1. One manufacturer may have a 5w oil which has the same viscosity as a 15w oil from a different manufacturer.

Probably, the previous owner replaced oil, and maybe even the springs.
 

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Discussion Starter · #3 ·
The orig owner didn't do anything, he left the rear with 19mm of spring preload and 0mm sag, the front forks had the preload and compression maxxed out because "she slams down hard from wheelies". The guy was most likely a moron and only replaced parts he ruined by dropping the bike.

I personally have set up the suspension and gotten the sag in spec with stock springs (as I belive stock springs). By harsh I mean on straight roads with expansion joints I feel each one is a mini ramp and I am landing with no suspension at all. I have never used the zip tie to see how much travel I am using on the front but the oil lines on the black dlc coating is only about half way down.
 

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The orig owner didn't do anything, he left the rear with 19mm of spring preload and 0mm sag, the front forks had the preload and compression maxxed out because "she slams down hard from wheelies". The guy was most likely a moron and only replaced parts he ruined by dropping the bike.

I personally have set up the suspension and gotten the sag in spec with stock springs (as I belive stock springs). By harsh I mean on straight roads with expansion joints I feel each one is a mini ramp and I am landing with no suspension at all. I have never used the zip tie to see how much travel I am using on the front but the oil lines on the black dlc coating is only about half way down.
Start by going with the 7.5w fork oil (golden spectrol) is stock, set the airgap at 120mm, and try, if your heavier than average, you may want to go to a stiffer fork spring, Linderman eng. (Ed Sorbal) can make you a set for your weight.
If you need to go heavier than a .85 fork spring, I would go to a 10w fork oil.
Aloha Alex
 

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What Alex said... I found the recs from the manual odd. I tried 5wt in the original cartridges with .85 springs and it was stiff/fast/harsh. Couldn't slow down the rebound. I also tried 10 and 7.5. I found 7.5wt to be the best. I was using amsoil because that is the best that the only shop in town carries and I was changing it so often. This is an 1100 right? Not an Evo? Also the first time I changed the oil the air gap was way off not only from what Ducati recommend but also from the 120 that Alex mentioned. Can't remember exactly what it was at but I thought it was weird because nobody had been into these before me.
 

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Discussion Starter · #6 ·
Yeah 1100s with marzocchis. I am about 185 in riding gear. So the 120mm would be measured from the inner leg down with just the spring removed not the 2 spacers. I used 5wt maxima oil but I guess thats a waste at this point. I just cant figure out why my forks are so over filled to start with.
 

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Stock, from Ducati, these forks had different oil levels from one fork to another on the same bike. Piss poor quality control.

Follow Alex's advice. You have another option of going with Traxxion Dynamics for springs too.


This should help with the oil:



Dave
 

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I tore into the forks today to do a fluid change. I have always thought they were a bit harsh so I went with 5wt fluid instead of the book spec 7.5. I removed 20oz of fluid from each leg which was about 85mm of air with just the spring removed (sliver shim and black spring spacers in the oil). The book spec is .48 cu.dr of fluid which is 16oz and 104mm gap from the top. So whats going on here, are factory levels all over the place or did the previous owner add in more oil? I have the forks set with the same 20oz right now so will I be ok or has that been my harsh front fork cause all along.
Yep, I have the same problem and the previous owner said he did nothing to the forks. I was trying to ask my local Ducati shop about it but after 3 attempts to try and ask the service tech with no response (AMS in Dallas), I gave up. So, now I am going to get into the fork myself just like you guys did and see whats up inside of the fork. It seems like it is hydraulic locking. I cannot get full travel out of the forks and they are a bit harsh. Too much air would make them bouncy, which they are not. Curious to see what you find out......I will follow this thread for sure.
 

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Discussion Starter · #9 ·
What is full travel for the non evo sp forks? What is the ideal weight for the stock springs? My bike doesnt ride terribly now but I still think it needs improvement.
 

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A few answers......

The stock Hyper forks (non Evo SP) don't travel all the way to the bottom of the inner fork tube like you would expect. The bottom bumpstop has the forks stopping about 1.25" from the base of the inner fork tube. So, placing a zip tie on the tube, it will NEVER hit the bottom casting of the fork, regardless of what you do.

Ducati claims that the stock springs on the non-Evo SP forks are .85 kg/mm, when in fact, they have dyno'd out at .66 kg/mm. This rate might be fine if you wieghed about 140-150lbs. However, the springs are progressively wound, further compounding the spring rate/valving issue with these forks.

The fact is, these forks are undersprung and over damped with mediocre valving and even worse oil. The rebound circuit works pretty well stock but the compression circuit is a light switch, all or nothing, and could benefit from better oil. They need heavier springs (for most of us) and a good quality oil that is still heavy enough to control your new springs rebound but light enough to allow the compression circuit to do its job.

So, for best results, without buying a cartridge kit, go through Traxxion Dynamics or Lindeman Engineering and have them calculate the proper straight rate spring for you. Then, depending on your body wieght/spring rate, you will need to pick the oil viscosity. Fill the fork tubes to somewhere around 120mm (+/- up to 10mm) air gap and give it a go. The air gap works as a bump stop, sort of. Too much air gap and you don't get full travel. Not enough and you bottom the forks out too easy.

I supplied an oil comparison chart in my post above. It's pirated so thanks to whoever I borrowed (stole) it from. You will notice the "(marzzochi)" just before the halfway point. That's the crap that is in our bikes....supposedly.

Best of luck,

Dave
 

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And when you're done - after all that work and everything - give up and put in a cartridge kit of your choice. I went with Andreani personally, and without touching a single knob from stock, the bike is vastly improved over any setting I previously concocted with the stock internals. I think my kit was around $700 and included the springs for my weight.

Pags
 

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And when you're done - after all that work and everything - give up and put in a cartridge kit of your choice. I went with Andreani personally, and without touching a single knob from stock, the bike is vastly improved over any setting I previously concocted with the stock internals. I think my kit was around $700 and included the springs for my weight.

Pags
I am a total of $130 into mine.

I would like the Traxxion AK-20 cartridge as I think it would be the best I could do for the forks but at $1000 before assembly and oil.....

Bottom line, I didn't have that kind of scratch for this project. I found that my solution (same as Alex's and several others) is a great (not just good) alternative without spending the big money for what these bikes really need, a different cartridge (and springs and oil).

Dave
 

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Agree - I've discussed this ad nauseum with a few guys I've raced with in the past, and they all agreed, that as soon as you can afford the cartridges, go for it.

Dave - weren't you selling a cartridge kit a while back though?
 

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my mechanic replaced my fork seals and used ohlins 0 weight. now i get a nasty head shake. he is blaming it on the tire (which is a brand new pirelli).

can the oil be reason for head shake?

i am at witts end and dont know what to do.
 

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my mechanic replaced my fork seals and used ohlins 0 weight. now i get a nasty head shake. he is blaming it on the tire (which is a brand new pirelli).

can the oil be reason for head shake?

i am at witts end and dont know what to do.
Could be......... stock oil is a 7.5w, and if your heavier than most, or have gone to heavier fork springs, you could even try 10w fork oil, NOT lighter than 7.5w Aloha Alex
 

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Like has been said many times before springs and fliud change set to 120 mm from top tube, makes a new front end. I have Traxxion .85 springs $140 and 125/150 26.7 on the chart and the front end is good for up to expert racing speeds. The front end can be be made better but it will take $1000 starting point.
 

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Had .959kg Racetech springs fitted with 90mm air-gap using 5 wt Motorex fork oil on my 08 Hm1100S. This set up has proven quite successful for my 100kg weight without gear. I have noted that the slightly lighter oil has made the compression circuit more responsive to adjustment and am still able to control rebound adequately with the heavier springs. The Racetech spring is a linear rate and the free length is longer than the standard spring fitted. So I did have the plastic preload spacer tubes shortened and machined to suit the springs. My set up was done in consultation with a respected suspension specialist, so would recommend taking the time to speak to similar where available in your locality.
 
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