Need to replace the springs on the forks for my m1100 evo. By far the worst set of stock springs I have ever owned. They don't even work for a 150lb rider in terms of preload. I think they were specifically designed for Dani Pedrosa, jockeys and the supermodels that sit on these bikes during photoshoots.
Factory service manual doesn't even have a front suspension section. On top of that, the technical data in the service manual shows the bike has non adjustable forks! I was able to confirm the oil weight as 7.5 thru the owners manual.
What I need to know is a recommended oil height from top measurement and fully compressed with spring or without?
Worst case if I'm in unknown territory here, I'll throw in the 445 Cc per leg noted and see where things come out.
. 95 springs ordered from racetech.
0.480 cc
104 MM
If following the shop manual sequence, the spring is installed after the fork oil measurement.
The above info is from the shop manual, Section 10.
BTW, if you are basing the fork oil weight by the Shell 7.5 designation be aware that there may/may not be consistency in that characteristic among the various manufacturers. In other words, one company's 7.5 may not be the same as another company's. Shell even explains that with the following statement in their fork oil literature, "This SAE Viscosity grade does not exist in the SAE J 300 specification."
You might want to see what other, if any, sections are missing from your manual.
Lots of info on the interweb explaining this bit of confusion. Just Google fork oil viscosity. Also lot of anecdotal examples of people using whatever fork oil is convenient, or has the prettiest label.
To add to the confusion, take a look at the note relative to Marzocchi fork oil at the bottom of http://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid (http://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid)
Time for the experts to sort this out for us. ???
Hmm.....Very Interesting
I dont have this Section 10 you speak of. My factory shop manual ends at section 9. Perhaps you'd like to share a link to your manual?
See below
(https://farm9.staticflickr.com/8752/16891075586_05d592d673_c.jpg) (https://flic.kr/p/rJBbi9)
Mine has the same listing as yours.
But, if you go to the parts fische section and select forks, that page will have a WSM link near the top right corner. Select that and it will open Section 10 forks.
(http://i165.photobucket.com/albums/u76/oldndumb/Shop%20Manual%20Parts%20Fische%20Link.png) (http://s165.photobucket.com/user/oldndumb/media/Shop%20Manual%20Parts%20Fische%20Link.png.html)
Thanks for the heads up. Still couldn't get the parts fiche to work until I figured out that the workshop manual is NOT Google Chrome compatible.
Works fine on internet explorer and per your picture it looks like it works on Firefox as well. Something for others to take note in the future.
-------------------------------
As for the fork oil weight. I need to do some double checking. Generally I've used Silkolene PRO and looking at the link you sent it seems like Silkolene PRO and Redline are preferred due to the high viscosity index.
The only catch is if I want much higher viscosity with the Silkolene PRO 7.5wt (12cSt @ 100C) or the slightly less viscosity of the Red Line (Light, Yellow) 5wt (7.1 cst@100C). I'm leaning towards the redline as this fork is way to stiff in its current setup and the higher rate spring I just bought should mitigate some of the front end dive.
Secondly, I highly doubt that road riding is going to result in fork oil temperatures reaching up to 100C. So my oil weight should be on the higher range regardless. Maybe a mix w/ Redline Yellow light and Redline Red Medium are in order
Still need to do some checking with redline.
To close on this topic:
Update - So doing some googling and talking to redline, the value to look at is actually the temp at 40 deg C. This is what forks generally operate at once warmed up. If you had a shock then you would look at the 100 deg C value
That said, the Cutsheet for shell Advance Fork 7.5 states that the viscosity at 40 deg C is 22 mm2 / sec = 22 cSt
The cutsheet for silkolene 7.5 shows cst @ 40 deg C is 37 cSt
See tables below.
(https://farm8.staticflickr.com/7281/16298178713_b49b41588d_z.jpg) (https://flic.kr/p/qQdqHg)
(https://farm9.staticflickr.com/8704/16918199455_a2d46b7423_b.jpg) (https://flic.kr/p/rM1ch4)
That said, if you choose silkolene, it's better to get 5wt to closer match for fork designed operation. 7.5wt in silkolene would be much stiffer.
Redline is generally a bit thinner at 5 wt and somewhat thicker at 10wt.
Use link below to establish mixture rates for redline or silkolene if you want it spot on.
http://www.provire.com/index.php/mtb/ (http://www.provire.com/index.php/mtb/)
Don't know where I got it from, but I was told that Marzocchi oil is rebranded Golden Spectro.
I have found pictures of Marzocchi fork oil containers and the bottom right corner of the labels had 7.5W printed on them in small print.
You may be right. Unfortunately, I'm just relying on info that ducati provides. Shell is specified in the 1100 EVO owner's manual at 7.5 weight. At some point I have to just assume that what ducati has written this as a viable weight and product and go from there.
Whether they physically use it in the factory is beyond my control. That said oddly enough, the Golden Spectro 7.5 weight is about 26 cSt @ 40 deg C which is similar to the 5 wt silkolene. It should translate over fine but because its viscosity index is 150 instead of 372, its a lower grade oil thats more prone to viscosity changes in relation to heat. Basically that means it will feel different at the fork warms up.
From what I've been hearing forks dont necessary get up to temp quickly.
The higher the index the less the variation in viscosity over the same given temp range. BTW - Redline is best at this.
I'm opting to go for the 5 wt silkolene now due to how hard it is to find redline oil locally. I'm in a time constraint and on a budget so I dont want to deal with online ordering at this time and redline would require (3) 16 oz bottles to generate the appropriate mixture instead of 2
yes, the cst @ 40 degrees c is the important spec. they all vary. i use maxima and their 5wt is as light as motul 2.5, around 15 cst.
i'd run the oil level around 140mm. this will reduce the effective spring rate rise as you get to maximum compression. if you want to play with it, drop it to 170 or so and bring it up in 10ml or so increments if it bottoms out.
0.95 is heavy for a monster.
I agree with you on the .95 racetech recommended it but I called them back and got. 90
Quote from: brad black on March 25, 2015, 05:10:17 AM
yes, the cst @ 40 degrees c is the important spec. they all vary. i use maxima and their 5wt is as light as motul 2.5, around 15 cst.
i'd run the oil level around 140mm. this will reduce the effective spring rate rise as you get to maximum compression. if you want to play with it, drop it to 170 or so and bring it up in 10ml or so increments if it bottoms out.
0.95 is heavy for a monster.
So Brad, I would love your input on the viscosity, do you think the duc forks work better with lower than 22 cst? I was considering 5 wt silkolene but would going with a lower wt oil give me better performance? Redline yellow is smack dab in the middle of silkolene 2.5 and 5
the lighter the oil the more closed you will have the adjusters meaning the more oil moves through the shim stacks. if the shim stacks are good, this is a good thing, if not, well, not. i don't know what the evo forks are like internally, from the parts list it looks like they're a long adjuster.
i generally always lean to 5 wt maxima on showa adj, but sometimes it's a suck it and see.
We'll, I bit the bullet and went with redline 5 weight and guess what. It works but too soft for my taste. Its not too far off from the Advance Fork 7.5 which is 22 cSt. The redline comes in at 18 cSt and considering that I found the existing fork setup way to harsh, I figured a reduction was in line.
HOWEVER after trying out the forks over the weekend. I went back and looked at the shop manual.
The owner's manual says shell advance fork 7.5 but the shop manual says Advance Fork 7.5 OR Shell Donax TA (an automatic transmission fluid). Looking at the Shell Donax specs the cSt is 34.9 at 40 deg C. If this is the case there is a huge variation provided by ducati without any clear info to the user as to the proper application. Based on the fork feel, I'm positive they went with Donax from the factory.
I will be changing to Redline Medium 10wt fluid that has a cSt midway between Advance Fork 5 and Donax TA. Hopefully this will help you guys not make the same error. Whatever fluid you guys use should be close to the high 20's or low /mid 30's range for stock valving.
You're on your own once you change valving.
Good info! [thumbsup] [clap] Thanks for sharing.
Probably right about the Donax. The pic in the shop manual shows them dumping red fluid into a pan. Donax TA, as most ATFs, is red. And we know the shop manual is infallible. :)
I know of at least one brand of fork fluid which is red, but do not think it is a common color. BICBW
did you try various adjuster settings?
crap recommendations from manufacturers is normal. aprilia say 5 to 20 weight, mix as you see fit.
Quote from: brad black on March 30, 2015, 01:39:55 PM
did you try various adjuster settings?
crap recommendations from manufacturers is normal. aprilia say 5 to 20 weight, mix as you see fit.
Yep.. Took a screw driver with me for a 120 mile ride in the mountains. I preset sag for 40mm (a little on the stiff side but seemed fine for my street riding). Compression damping just wasn't there. 3/4" of the way thru the ride, I ended up turning the compression adjuster in almost all the way in and then tuned the rebound accordingly with the help of another local biker.
are these marzocchi? i missed that bit. i always run 10wt in marzocchi, unless i have a strong reason not to.
Quote from: brad black on March 31, 2015, 12:40:03 AM
are these marzocchi? i missed that bit. i always run 10wt in marzocchi, unless i have a strong reason not to.
Yep. The evo versions run marzocchi. I am starting to think its a downgrade to cut costs for having TC & ABS
What cSt 10wt do you run. That way future tinkerers can reference an apples to apples comparison
the maxima is 36 i think. most 10 are pretty consistant 32 - 36 from what i've seen.
You would not believe the variation.
Maxima 10wt falls in at 37.4 per their site.
Silkolene runs their pro rsf 7.5 wt semi synthetic at 37. But if you buy their 5 wt fully synthetic, it is 43!
To close on this thread. For my marzocchi's, I swapped out the redline 5wt that was too soft with redline 10wt.
Spring was .90 in both conditions.
HOLY FREAKING CRAP!! Handling nirvana attained! 30 cSt is the magic number. Look for an oil around that number. I'm anal so I chose redline 10wt but forks aren't that hard on the oil as shocks. I bet even the budget brands would work well as long as you stay around the noted cSt @ 40 deg C.
Oil level from top, fully compressed, no spring or spacer was 103mm.
Preload set to 40mm.
The compression valve on this fork is decent but the stock rebound sucks. Since rebound and compression kinda mingle together. I will list both values below.
Rebound: only 1 full turn out from fully closed.
Compression : 2 turns out from fully closed.
Quote from: EEL on March 30, 2015, 11:33:19 AM
We'll, I bit the bullet and went with redline 5 weight and guess what. It works but too soft for my taste. Its not too far off from the Advance Fork 7.5 which is 22 cSt. The redline comes in at 18 cSt and considering that I found the existing fork setup way to harsh, I figured a reduction was in line.
This is really interesting! Like the forks on my 796 but feel they can run smoother with a better oil but the Shell 7.5W which is in there is otherwise in the ballpark. Had planned on trying the Red Line 5W because my dealer/Ohlins tech is a Red line junkie. 10W @ 30.4 looks stiffer than I might like.
FWIW, on many BMW's I've owned which called for 10W, a change to Spectro 10W completely smoothed them out and others who tried this change reported a great improvement.
Spectro make a Cartridge Fork Oil 125/150 which even says 7.5W on the bottle. cST is 26. Now I'm thinking I might try this as the 10W I used to use felt more like an 8W vs other brands.
Will be following the feedback on this thread as my service is coming up in 500 miles.
You and I were thinking the same thing..Ducati is running 7.5W shell. So I tried to back off a tad on 7.5W shell cSt and adjusted accordingly with redline 5w which was 18cSt. The problem is I could tell immediately when I poured out the stock fluid that it was much heavier than what I was putting in. In reality it should have been similar.
I now think Ducati uses Shell Donax Automatic Transmission fluid (also mentioned as a substitute for the forks). The redline 10wt is about 15 percent lighter than the Donax spec and seems to help significantly in absorbing bumps.
Be careful with anything lower than 30 cSt. I got really bad performance. Also you have to take into consideration that I replaced springs at the same time with a stiffer set. Most ducati forks are undersprung so the higher cSt oil helps reduce the pogo effect.
If you're in there replacing oil I suggest you spend a small amount of extra money and get new springs for your bike. Especially if you are reducing the oil weight. I honestly cant vouch for what will happen if you change the oil weight without upgrading the spring. All I can say is that an upgraded spring with 5W redline (18cSt) was crap.
That said, your 796 runs non adjustable forks so there may be a slight variation in results. Also I think yours run separate rebound and compression circuits in different fork legs and that might have some different effect. (Dont quote me on that. I'm not 100% positive.)
Agreed with all that and I hear you. For me @ 175# plus gear, the stock fork springs are just fine. The cST of the Shell is 22 and as I said, it's in the ballpark. The Spectro is 26 and as I mentioned seems lighter because it's smoother. The issue with the 796 was the Sachs which I ditched before delivery for a DU-737 Ohlins and spring for my weight. It's been set up by my dealer, so that may also figure into the fork-loading.
You might be right about the M796 valving. The legs take 500cc each per my manual, so 1 L handles it.
Interested to find out how it turns out. Keep us apprised.
Quote from: EEL on April 05, 2015, 10:25:36 AM
Interested to find out how it turns out. Keep us apprised.
Sorry, our posts crossed! ;) If in fact my forks have red oil in them, I'd presume that's Donax. Then 10W Red Line would be fine and probably an improvement in smoothness. If mine has 7.5W Shell, as it has Shell stickies everywhere, then the 7.5W Spectro cartride oil @ 26 cST might be better. I'll ask my dealer whether he has tuned any 796 forks in the past two years. He's as fussy as I am. I'm looking for what I have now, only smoother. That's for street compliance/comfort/control.
Will keep you posted. Might be a month or two. He's 140 miles from me and I need my service light to illuminate before he does the service and other stuff I need. Sadly Ducati's service light can't be extingushed before it illuminates, otherwise I'd have had this stuff tackled when he was slower during the winter. :'(
Quote from: EEL on April 05, 2015, 10:25:36 AM
Interested to find out how it turns out. Keep us apprised.
Finally reached my dealer/tech today to discuss my servicing list. 8) Without specifically asking, he voluteered that they've been using the 10W Red Line you called "nirvanah" for the past ten years on Marzocchi forks. Seems you have the "hot ticket". Only on a few Ohlins does he use the Ohlins fluid.
Could be a month before I can get up there though! :'(
Quote from: Curmudgeon on April 08, 2015, 04:57:20 PM
Finally reached my dealer/tech today to discuss my servicing list. 8) Without specifically asking, he voluteered that they've been using the 10W Red Line you called "nirvanah" for the past ten years on Marzocchi forks. Seems you have the "hot ticket". Only on a few Ohlins does he use the Ohlins fluid.
Could be a month before I can get up there though! :'(
I may have had the "hot ticket" but that ticket cost me 2 saturdays of dissessembling and re-assembling forks, a nasty pinch on my finger when putting the fork cap back on and about an extra 30 bucks 5 weight fork oil that I literally installed and just poured straight into the oil recycle bin.
Only consolation is that I'm done for a long time.
that's the price of experience and expertise.