Fork oil change
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Fork oil change
Hi, sorry I'm sure that tis question have been asked before but my german is below zero !
I would like to know if in order to chage oil fork I have to unmount all the fork or just unscrew this bolt ? (Both side) thank you for any help.
Patrick
I would like to know if in order to chage oil fork I have to unmount all the fork or just unscrew this bolt ? (Both side) thank you for any help.
Patrick
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- scrambler
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Re: Fork oil change
Hi Patrick,Zigomatix hat geschrieben: ↑So Jan 26, 2020 12:13 pm Hi, sorry I'm sure that tis question have been asked before but my german is below zero !
I would like to know if in order to chage oil fork I have to unmount all the fork or just unscrew this bolt ? (Both side)
DSC_0137.JPG
thank you for any help.
Patrick
yes, that's the bolt to drain the fork oil. Just push the fork a couple of times upwarts to pump out as much of the old oil as possible.
sauve qui peut
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Re: Fork oil change
Hi there.
I had a problem, I realise my fork was twisted. A friend of mine is currently fixing it.
I would like to chage oil type in order to limit the fork's sinking when braking. I already hardened the springs with 8 cm wedges.
Original oil is 15W.
Does anyone tried 20W ? or maybe 30W
I read that we can mix oil then 1l of 20W + 1l of 30 W = 2l of 25W (if same brand)
Any advice ?
Thx
Patrick
I had a problem, I realise my fork was twisted. A friend of mine is currently fixing it.
I would like to chage oil type in order to limit the fork's sinking when braking. I already hardened the springs with 8 cm wedges.
Original oil is 15W.
Does anyone tried 20W ? or maybe 30W
I read that we can mix oil then 1l of 20W + 1l of 30 W = 2l of 25W (if same brand)
Any advice ?
Thx
Patrick
- scrambler
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Re: NX250 fork oil change
Well I don't, the thickest oil I've tried is a 15W. You can mix different viscosities of the same brand, but I don't think a 20w or 30w will prevent fork dip.
You have already exchanged the short springs for rigid tubes, actually the suspension should now be hard enough for a driver's weight of approx. 80kg. You have to live with a certain amount of fork dip with the long suspension travel.
sauve qui peut
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Re: Fork oil change
OK thx Scrambler.
I don't want to prevent fork dip when braking ! just limitate it.
I am going to give a try to 20w oil. I'll let you know.
I am using my bike 100% on road so...
I now have 2 forks, one straighten out, I will leave it with 10W oil, the orther with 20W oil.
I don't want to prevent fork dip when braking ! just limitate it.
I am going to give a try to 20w oil. I'll let you know.
I am using my bike 100% on road so...
I now have 2 forks, one straighten out, I will leave it with 10W oil, the orther with 20W oil.
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Re: Fork oil change
Hi Patrick,
when adding a 8 cm wedges it won't hardends the spring but will higher up the breakthrough moment. Sounds good but reduces comfort and responsiveness.
Higher viscosity of forkoil has the same Effekt. In smaller turns it is okay for technical Tuning but a double of viscosity no more.
To reduce sinking because of the higher weight of driver and bikeload a spring with progressive and/or harder ratio is recommendable.
Wilbers and Wirth have those spring in there portfolio:
https://www.wilbers.de/shop/en/Motorcyc ... ssive.html
https://www.wilbers.de/shop/en/Motorcyc ... ssive.html
https://www.wirth-federn.de/produkt/wir ... a-u-ie-kb/
Regards
Peter
when adding a 8 cm wedges it won't hardends the spring but will higher up the breakthrough moment. Sounds good but reduces comfort and responsiveness.
Higher viscosity of forkoil has the same Effekt. In smaller turns it is okay for technical Tuning but a double of viscosity no more.
To reduce sinking because of the higher weight of driver and bikeload a spring with progressive and/or harder ratio is recommendable.
Wilbers and Wirth have those spring in there portfolio:
https://www.wilbers.de/shop/en/Motorcyc ... ssive.html
https://www.wilbers.de/shop/en/Motorcyc ... ssive.html
https://www.wirth-federn.de/produkt/wir ... a-u-ie-kb/
Regards
Peter
NX 650 RD02 Bj 1993
CRF 1000 SD06 BJ 2018
CRF 1000 SD06 BJ 2018
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Re: Fork oil change
'thicker' Oil in forks will result in slower rebound.
much thicker oil = very slow rebound
if the fork has to absorb multiple obstacles in quick succession it might not return to it's unloaded position until all obstacles are cleared.
in other words: if the oil is to thick the fork will stay 'short' and might become 'shorter' for as long it is constantly loaded.
much thicker oil = very slow rebound
if the fork has to absorb multiple obstacles in quick succession it might not return to it's unloaded position until all obstacles are cleared.
in other words: if the oil is to thick the fork will stay 'short' and might become 'shorter' for as long it is constantly loaded.
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Re: Fork oil change
After lot's of searching and finally advised by a racing builder, did the following set-up.
ENI Fork oil SAE 10W in combination with new Wirth fork springs and spring tensioner adjustment bolts for fine tuning.
Best set-up advice ever had. Also use this set-up on my two CB500XA bikes, with oem fork springs.
ENI Fork oil SAE 10W in combination with new Wirth fork springs and spring tensioner adjustment bolts for fine tuning.
Best set-up advice ever had. Also use this set-up on my two CB500XA bikes, with oem fork springs.
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Re: Fork oil change
Good thinking!
There are TWO main things at work in a simple fork:
In theory the 'rebound holes' (the upper ones) in the dampening tube would have to be adjusted to the higher spring rate. No idea how.
There are TWO main things at work in a simple fork:
- Spring Load
Dampening
In theory the 'rebound holes' (the upper ones) in the dampening tube would have to be adjusted to the higher spring rate. No idea how.