juice clutch fluid

[ml36]

what kind of alternative fluids are you guys usings in your clutches? i've heard of using sythetic atf and 2.5 wt fork oil. from what i know about hydraulics, the light the fluid the easier it flows, therfore reducing clutch pull. the 2.5 wt fork oil sounds like a good idea. atf is approx 8 wt, making for a harder pull. both fluids have the same compressibility, leaving the clutch pull directly related to viscosity.

tell me if you think i'm wrong, doubt it

marc
'01 520 mxc

 

[TM-Frank]

I have tried ATF, Fork Oil and Baby Oil (with Camomile Extract!), everything works. The baby oil gave the lightest pull of the three.
But don't expect miracles! The difference is not as big as some people might tell you.

Frank

 

[yota]

KTM advises use of mineral oil such as you would get in a drug store. I have used that for 3 years. It is very inexpensive.

 

[Jaybird]

Type F ATF...in the forks, in the gearbox, and in the juice clutch. I'd use it in my fuel if it would burn better. :)

 

[TM-Frank]

...and in the morning you are gargling with Type F ATF? ;)

 

[Jaybird]

LOL...No, but it's GR8 on toast!

 

[TM-Frank]

OK, this is Off-Topic

Hey Jaybird!

You remember my question concerning Type D and Type F ATF in "Advanced Tech & Eng."? Someone gave a link to another topic where Ando said that Type F contains friction intensifying additives to achieve better clutch pressure.
Now I'm wondering: Do I want friction intensifiers in the fork or in a hydraulic system like a clutch actuation? What do you think?

Frank

 

[Jaybird]

I think those additives are designed to work at a higher rate of speed. Your forks and clutch are moving at a very slow rate in comparison to the clutch plates. I feel there would be no effect from these intensifiers. I think that you will probably get the same response from Jeremy if you ask him. My opinion is that you could use any type of ATF in both the forks and the clutch, but since we know it's better for type F in the gearbox, you should stick with that for economy and confusions sake.
I buy it by the case.:D

 

[jeb]

I use 5-10wt fork oil. I have since we got our first juice clutch on our 98 KTM 125E. Works great. Mineral oil in euro terms is hydraulic fluid in US terms. Fork oil is just that.

 

[Jaybird]

Mineral oil in euro terms is hydraulic fluid in US terms.

Are you certain about that?

 

[TM-Frank]

I am not.

 

[marcusgunby]

when KTM quoted mineral oil it isnt what US people think of as mineral oil.Ive heard of people going to the drug store to buy it-this sint the right stuff.Ive used 2.5wt fork oil for 3 years with zero problems and a lovely smooth light pull-why try anything else?

 

[Greg in Oz]

Have been using Maxima rear shock fluid in my Berg's clutch cyl for 2 years now. Absolutely no probs. I think its 2.5 wt anyhow its purple. The thinner oil not only lightens pull but makes the bleed process easier cause the syringe forces the oil up the line with less force required.

 

[TM-Frank]

Yes, but when the viscosity is too low there is the danger that the liquid sipps past the rubber seals. Another thing is, the higher the viscosity the better the lubrication.
Has anyone ever tried a liquid with extremey low viscosity like alcohol? Just curious.

Frank

 

[marcusgunby]

Like i said the 2.5wt has a thin enough viscosity to make the pull lighter but no side effects.Ive seen one problem where fluid was leaking past the o ring in the slave cylinder but that was because the o ring was worn.10wt would have leaked past after a few more rides.

 

[Jaybird]

When I see mineral oil, I don't think drug store oil...I think mineral "seal" oil, which is the same thing as what is in the juice clutches. It is also used as a base carrier or part of the package for many lubricants as well.

 

[jeb]

Originally posted by Jaybird

Are you certain about that?

That's what I've read here and on other forums about the mineral oil. Be nice if one of the euro guys would jump in and confirm that, though.

 

[Strick]

Mineral oil

Jeb is right. The 2002 rfs manual is very specific about what mineral oil is.

 

[Jaybird]

Folks, hydralic oil...or "circulating oil" is not mineral oil. Most hydralic oils are blended for use in industrial hydralic systems and most have additives to eliminate oxidation. This helps the fluid to resist acid buildup that normally occurs in common petroleum products. They are ususally a zinc free package. They also help to inhibit varnishing. Some grades of hydralics are blended from base petroleum stocks and are compatible with seals...this would be the only relationship that hydralics would have with mineral seal oil. Many hydralics are blended to be fire-proof(or near it), as many circulating applications in industry require it.

The only confusion on mineral oil is that some may think it's drugstore rubbing oil, which it's not what we are talking about.

 

[Strick]

Jaybird: I think that is was Jeb and I are saying. I don't mean to speak for Jeb, but I have used fork oil in my clutch, and it works great. Unless you are saying that fork oil or ATF is not the correct 'fluid'.

However, per KTM, don't go to the drug store and buy 'mineral oil'.

I will try to remember to grab my manual and post the manual's exact wording.

 

[Jaybird]

I'm not saying that at all. I use ATF in my juice clutch and it is quite fine for that application. Both ATF and 7wt fork oil have a slightly easier pull than the OEM oil KTM provides.
All I'm saying is that there is a confusion sometimes when we hear mineral oil. The confusion is that we also have a product in drugstores that is called "mineral oil" and it is NOT the mineral seal oil, that KTM uses. Also, mineral seal oil is not whats marketed as "hydralic fluid" although a juice clutch is a hydralic type application.
Magura hydralic clutches will probably function with ANY fluid. Just some oils are caustic and can ruin seals fast. Some fluids are way too viscous and can blow seals as well.
Fluids like brake fluid are diabolic for the ruin of seals.

I'd like to add this for the poster: If you change out your fluid (2.5wt fork oil is fine btw) just be sure you don't fiddle around trying to fill it from the reservoir. You absolutely need a big syringe to do this. Just get a piece of 1/4 o.d. tubing and put it on the end of a big cow syringe. KTM sells syringes but are a big waste of good money. Just go to a feed store and get a pack of 3 for a few bucks. ANywho....put the end of that tubing over your bleeder screw, loosen it, and fill it from there. Have the syringe full and push it till the fluid fills up the reservoir. Tighten the bleeder while the tube is still on.
Trying to fill from the res. and bleeding by pumping the lever is futile and you will never get all the air out.

Hey ml36...I see you are from Bloomngton. GO IU! :)

 

[Strick]

Direct from KTM 2002 RFS manual

"KTM uses biodegradable hydraulic oil for the hydraulic clutch control. Never mix biodegradable hydraulic oils with mineral oils. Always use biodegradable hydraulic oil SAE 10 to fill up the master cyulinder. Never refill with mineral hydraulic oil or brake fluid."

O.K. there it is. Unless something has changed since yesterday, fork oil is NOT biodegradable, and neither is ATF.

I don't know if I am eating my words or living a bad dream.

Here is my take; don't use drug store oil (Mineral hydraulic fluid), and don't use brake fluid. Where do you get biodegradable hydraulic fluid?

Oh well, 10wt fork oil in the bike for 2 1/2 years with not leaks or failures, not even the need to bleed. I guess it's o.k.??

Someone else care to interpret?

 

[Jaybird]

First, mixing is the key here. Adding one oil to the other is a bad thing. This holds true in just about any application. Second, get the drugstore stuff out of your head. It is not what is being talked about here.
No matter what fluid you use, it probably will oxidize over time. Just like it does in our forks, so a change is warranted from time to time.

You think I'm full of seal oil, don't you? BTW...seal oil is not a derivitive of a water creatures blubber.
:confused:

 

[marcusgunby]

Im not sure weather you two are argueing or agreeing.Can we all just use 2.5wt fork oil and then im vindicated.

 

[Strick]

Originally posted by marcusgunby
Im not sure weather you two are argueing or agreeing.Can we all just use 2.5wt fork oil and then im vindicated.

Marcus.. Neither do I :confused: