Fork me oil ?.

[Nanna10r]

Ok time to learn some stuff.
Fork Oil
I understand what it does sorta but never pulled scoot forks apart so not sure how it does it.
Neil P mentioned the other day to Yappa to throw some 5 weight in the 6r while i've heard others suggest going to heavier weight oil, so what gives ?.

Enlighten me oh Kwika Brethren & Yoda lo-tech it for me mate please..... thanks heaps blokes.

Cheers Brett

[Felix]

Umm, what I know is you have a piston moving in a tube with some holes in it (a valve even) and depending on how viscous the oil is, depends on how easy the piston moves up and down. So it can affect your damping rate moving from one weight of oil to another as it provides either more or less resistence to the piston.

So if it feels a bit spongy, then a heavier weight oil might help tighten it up, but so might just overhauling the forks back to standard. Things do wear out. I've heard other people talk about messing with the oil level, but I kind of like to keep things in spec. Although, I did actually wuss out and give it to Steve to fit gold valves...

[Barrabob]

Got a manual brett? its piss easy on the fizzer just loosen off the caps on top and jack the front up then undoo the caps and your fork springs and spacers come out....keep them in the same order they came out and give them a wipe down also note if they are a straight wind or progresive(smaller windings one end).

Undo the 8mm bolt at the bottom of the forks and something resembling mud will run out the bottom of the fork leg once you think its stopped pump the forks a little to get the last of it out.

Consult the manual as to the correct weight oil to refill with if it says 10 weight try 15 weight and it should also mention a oil height inside the forks with them in the right down position without springs or spacers like 100mm from the top of the fork tube but it varies from bike to bike.

Fill with oil and measure then pump up and dow to get all the air out of the system and remeasure the airgap at the top of the forktube and adjust the gap accordingly.(dont panic if you overfill just let it back out of the drain at the bottom.

Put back your springs and spacers and put the caps back on the top and enjoy.

Cant comment on the fork oil rate without knowing whats already in there.

[MadKaw]

Not that easy on the 9.. They have no drain holes at the bottom.
You have to take the forks out and drain them from the top..
The valves are probly worn so a thicker oil may be the go. I ran 7.5 wt in mine as the std weight is 5.
The std weight oil for your bike is 10 so I'd probly stick with it being a light weight..
Its well worth the effort as the stuff in it will be like sludge..
You will need to get the dimension from the top of the tube to the oil level to get the quantitiy correct. Don't rely on the 535ml per side info as it will not be acurate. On the 98 model the dimension was about 150mm but to stiffen it up a little in the last portion of the stroke I would put about 142 ish in...

[Smitty]

Not that easy on the 9.. They have no drain holes at the bottom.
You have to take the forks out and drain them from the top..
The valves are probly worn so a thicker oil may be the go. I ran 7.5 wt in mine as the std weight is 5.
The std weight oil for your bike is 10 so I'd probly stick with it being a light weight..
Its well worth the effort as the stuff in it will be like sludge..
You will need to get the dimension from the top of the tube to the oil level to get the quantitiy correct. Don't rely on the 535ml per side info as it will not be acurate. On the 98 model the dimension was about 150mm but to stiffen it up a little in the last portion of the stroke I would put about 142 ish in...

well I was gunna launch a post
but Dave pretty much said it all

cupla things though.....you can mix oils
try a 50/50 5w and 10w ..to get 7.5w (I have dun this)
also
the weight of the rider is important in mucking around with this sorta
stuff
but as a hint, a tip....
I would start with doing it all to standard (as per the factory)
replace the fluid with standard weight oil, set the fluid level to standard
set the front forks standard height thru the clamps
and see what ya reckon
you might find that the front end becomes fantastic again
but if not happy, then start a fiddling..heavier weight oil
or more oil or stiffer springs or..etc etc

cheers

[Steve_TLS]

cupla things though.....you can mix oils
try a 50/50 5w and 10w ..to get 7.5w (I have dun this)

Yes you can mix oils, but a 50/50 of 10 and 5 doesn't give you 7.5WT, there are some specs out their, I'll try and find them. A 50/50 of 10w and 20w gives you 13.3wt

[Jonno]

Good time to replace/check the seals if you have the forks out.

[Smitty]

cupla things though.....you can mix oils
try a 50/50 5w and 10w ..to get 7.5w (I have dun this)

Yes you can mix oils, but a 50/50 of 10 and 5 doesn't give you 7.5WT, there are some specs out their, I'll try and find them. A 50/50 of 10w and 20w gives you 13.3wt

yeah I know that ...
50/50 5w and 10w actually gives sumfing about 7.2-7.3w
but 7.5w is close enuff for the example
donwannabe too technical here


cheers

[Steve_TLS]

Gotcha!

[Smitty]

Gotcha!

huh..???

[Steve_TLS]

Gotcha!

huh..???

This

yeah I know that ...
50/50 5w and 10w actually gives sumfing about 7.2-7.3w
but 7.5w is close enuff for the example
donwannabe too technical here


cheers

[Neilp]

Without getting too technical, adjusting the air gap at the top of the forks can make a big difference too, ie putting more or less oil in the forks.
It is very important to take care measuring the amount of oil in each leg, make sure you have pumped them up and down to remove any air in the piston and that they are level when checking the oil level. A vice (with soft jaws) sitting on the concrete is ideal for holding the fork legs to work on.

[Smitty]

gotcha...

ok
lets get technical

first a few assumptions....
we are going to be dealing with oils from the same base stocks and both are mineral oils and both come from the same manufacturer
(different manufacturers use different formulations) and we are NOT dealing with multiviscosity oils (like car engine oils)

so
lets take 100mml of 5 W fork oil....
its is made up of 90mml of actual 5w oil and the other 10mml ?
...is various detergents antifoaming agents and viscosity stabilizers.
and now
lets look at 100mml of 10w fork oil
it is made up of 85mml of actual 10w fork oil and the other 15mml is the various detergents antifoaming agents and viscosity stabilizers.

so what have we when we add them together?
175mml (or 87.5% of the total) of actual oil with an average weight of 7.5w and 25 mm of additives
and simple maths gives an oil weight of 6.6w for the 200mml

(I have exaggerated the differences here for examples purposes, but is known that as oil weight goes up, increases in the various additives as a proportion of the final product are needed.)
btw
this gets even messier when you start considering that the various additives may have viscosities from say from..1 to 10
but I thought I would ignore that, as I don't wanna be too technical

cheers

[MadKaw]

FFS... You guys...
Just go and buy some Silkolene 7.5wt oil if you want that weight..
others make it too...

Stock is 10wt so I probly wouldn't go less anyway....

[Neka79]

heres a tip...
DONT let jamie newhere near ur forks..or ull not have ne for many weeks..
apparently the zx6r DOESNT have drain holes at the bottom...lol..