Monster 1100 evo suspension details needed

[EEL]

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.

[oldndumb]

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

Time for the experts to sort this out for us. 

[EEL]

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

[oldndumb]

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.

[EEL]

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.

[EEL]

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.





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/

[oldndumb]

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.

[EEL]

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

[brad black]

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.

[EEL]

I agree with you on the .95 racetech recommended it but I called them back and got. 90

[EEL]

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

[brad black]

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.

[EEL]

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.

[oldndumb]

Good info!     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

[brad black]

did you try various adjuster settings?

crap recommendations from manufacturers is normal.  aprilia say 5 to 20 weight, mix as you see fit.