Marzocchi 45 shim advice?

[twowheels]

Seven point five.

[Jakobi]

...But oils aint oils!

[32:1]

Originally Posted by Jakobi

...But oils aint oils!

Im using Motul and have done for years

[Jakobi]

What I mean is that even comparing one brand of 5wt to another brands 5wt doesn't mean they are the same viscosity.

[motopsycho87]

It's supposed to have 7.5wt oil. I put valvoline maxlife atf in mine as it works out around 7.5, dexron 2 and 3 are closer to a 10w but if I were you i'd aim for about 12.5 at the very least.

http://mahonkin.com/~milktree/motorcycles/fork-oil.html

Bare in mind you won't find a 12.5w fork oil so select a thinner 15w from the list. Also, while your low speed (round edged bumps) damping may improve, your high speed damping will get harsher (sharp edged bumps).

[pscook]

Originally Posted by motopsycho87

It's supposed to have 7.5wt oil. I put valvoline maxlife atf in mine as it works out around 7.5, dexron 2 and 3 are closer to a 10w but if I were you i'd aim for about 12.5 at the very least.

http://mahonkin.com/~milktree/motorcycles/fork-oil.html

Bare in mind you won't find a 12.5w fork oil so select a thinner 15w from the list. Also, while your low speed (round edged bumps) damping may improve, your high speed damping will get harsher (sharp edged bumps).

If you can't get 12.5 oil, mix equal quantities of 10w and 15w of the same brand/type of oil to achieve 12.5w. I used to do this for my road race bike for early/late season (15w for cold weather), 17.5 for mid season (15w+20w), and 20w for a particular track in the hottest month. Plus it kept the oil fresh.

[Jakobi]

The labelled weights don't mean much. The viscosity is what matters.

I believe the Marzocchi 7.5wt is around 26.40@40cSt and 9.90@100cSt
In comparison Silkolene RSF 5wt is 26.70@40cSt and 9.46@100cSt

Thats just one comparison. Also, regardless of what the manufacturer recommends, its also just another tuning variable and more importantly is selecting a particular oil and working with it to achieve the desired goals. A lighter oil will pass through the valves quicker. Lighter compression damping, and a faster rebound.

In my closed chamber I've been using Amsoil 5wt hich is only 15.9@40cSt and 4.4@100cSt.

[32:1]

Well Ive been playing around with these 45's and think Ive got it dialled now.

Ive made from delrin 20mm spring spacers to give the fork a bit of help as I felt it had a lot of sag and soft feel in the first part of the stroke, as well as going from my 5wt oil up to 10wt. Oil level was good as it resisted bottoming by around 10mm landing on flat ground from a 6ft drop. The fork now feels a lot more progressive in its travel, and does not dive through the first half as quickly.

Ive a day woods riding planned this weekend so time will tell, just hope it don't start pushing the front in corners or over roots