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650R which fork oil weight ?

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As topic I am planning on changing the oil, manual just says fork oil and that's it, some mention 2.5wt oil and some 3wt just wondering what is best for mild off-roading nothing heavy....:smirk: would rather have the comfort :smirk:

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I have run 5wt & found it to work well. If you search there is a good thread on rebuilding somewhere with bunch of good info.

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I have run 5wt & found it to work well. If you search there is a good thread on rebuilding somewhere with bunch of good info.

I have read the thread but it mention's 2.5wt and 3wt just wanted to clarify which would be best, might take your advice and use 5wt. Strange how manual doesn't state which grade of oil to use ?....just says fork oil

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Nobody can answer this. Completely depends on you valving.

Borynack's arguement is that that lighter weight oils have less change in viscosity when forced through a change in temperature (fork oil gets hot when worked hard).

He includes a graphic on his page with tests of a lot of oils.

From there, you'd have to have your valving set-up to accept light oil.

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is your spring rate stock? have you done any mods to your forks? what type of riding do you do? what do you weigh? those are all variables in depending on what you need.

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ATF. Synthetic. I use ATF +4. Cheaper, better.

+1 :ride:

I use ATF Synthetic in my stock forks and am happy with the handling. I do about 80% off road, 20% on road.

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+2 on the ATF.

I recently flushed and filled my 650L forks with ATF. BIG difference in suspension action (better). I filled with 19 Oz and my fork setting is on #3.

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Well order some Silkolene Pro RSF 5wt Racing Fork Oil today, will see how it goes, seems popular as 78 other people had brought it :ride:.

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With stock forks and mild off roading you would likely never be able to tell the difference between 2 1/2 W and atf.

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With stock forks and mild off roading you would likely never be able to tell the difference between 2 1/2 W and atf.

Mines not 2.5 it's 5, and I feel happier sticking fork oil in rather than ATF that's what the book says.

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Mines not 2.5 it's 5, and I feel happier sticking fork oil in rather than ATF that's what the book says.

Fine, even less difference. A fork leg is essentially a hydraulic cylinder. Fork oil and atf are basically just hydraulic oil. Fork oil venders don't manufacture their own products, oil companies do. For the extra $8-10 dollars a bottle you get some pretty blue, green or red dye and maybe a little closer quality control regarding viscosity.

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People have been using ATF in forks for decades ... I seem to recall professional racers also using it (Baja, Paris to Dakar, etc.). It also used to be listed in the manuals of most dirt bikes as the recommended fork oil.

FYI, an automatic transmission has a lot more rubber compounds and sees a lot higher pressure than the forks on a dirt bike. :ride:

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These ultra low viscosity oils are only needed in highly modified and aggressively ridden forks where temperature variation could affect viscosity and thereby consistency. Most people would be hard pressed to feel any difference. 5W vs atf negligible, atf vs 20W vast.

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These ultra low viscosity oils are only needed in highly modified and aggressively ridden forks where temperature variation could affect viscosity and thereby consistency. Most people would be hard pressed to feel any difference. 5W vs atf negligible, atf vs 20W vast.

I don't disagree to what your saying I just feel happier sticking fork oil in my forks rather than gearbox fluid, fork oil isn't megga expensive but thinking about it ATF fluid over here is expensive lol.

Glad it works for you guys but I am sure my fork oil will do me just fine, the stuff which came out wasn't to clean or pretty...wasn't exactly whale snot as mentioned but it was slimey and hard a lot of dirt in it.

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