Honda Twins banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4,458 Posts
Discussion Starter · #1 ·
Ok so I think it's about time for me to change the fork oil on my bike.
Now the Honda Service Manual says to use ATF which is what I used on the bike last.

My question is would it be better to use fork oil instead?
What does everyone use on their bikes?

What makes fork oil better than ATF?
 

·
Registered
Joined
·
4,458 Posts
Discussion Starter · #3 ·
ATF is definitely cheaper and more readily available than fork oil.
Other than the fluid viscosity and weight, I'm just curious if there was any additives in fork oil that would benefit the bike.
 

·
Registered
Joined
·
623 Posts
Fork oil supposedly has conditioners that help keep the rubber seals from hardening up. ATF has detergents in it that might help remove sludge when you change out the oil. ATF also has strong shear wear properties (long chain molecules that reduce the propensity for it to break down and lose viscosity), so it might or might not last longer than fork oil. The main concern, though, is the viscosity- if you've swapped out to stiffer springs, or the forks aren't adequately controlled by installing fresh ATF, you've got pretty much no other choice than to go with fork oil of the proper viscosity.
 

·
Registered
Joined
·
2,837 Posts
I ordered a bunch of different weight fork oils years ago to experiment with, as well as progressive springs and different length spacers. It was easy to make the forks way too stiff. I wasn't real scientific about recording results but I just use atf these day. I got emulators in the racers forks that I can't wait to try out. I think a lighter oil and progressive springs is a good combo and the later year damper rod forks are definitely better.
 

·
Registered
Joined
·
892 Posts
ATF is all over the board viscosity and additives wise now compared to years ago when there were only a few types.

I have been using Pro Honda Suspension Fluid SS-8 10 Weight for my 350 forks. It was developed by Showa and on the back panel says to use wherever ATF is recommended.

Not cheap compared to some ATF but having gotten deep into rebuilding Ohlins shocks and paying close to $50 for a litre of their fluid it is cheap.
 

·
Registered
Joined
·
4,458 Posts
Discussion Starter · #7 ·
Pretty much from everything I have been reading so far tells me the only advantage in using fork oil is the viscosity rating (5w, 10w, 15w, even 20w) on the bottle.
Whereas with ATF you really have no idea what the viscosity really is.
 

·
Registered
Joined
·
2,837 Posts
I remember doing a project in school where we dumped stuff down a board and timed it to measure viscosity. Tools said its 8 and that sounds about right. I read that water would be the perfect damper fluid if it didn't cause corrosion or something like that.
 

·
Registered
Joined
·
4,458 Posts
Discussion Starter · #9 ·
Well since it ain't broke, I chose not to "fix" it and changed the fork fluid with ATF again. Using Mobile 1 Synthetic ATF this time and the suspension feels good while riding.
Only bad part was the god awful smell from the old ATF :eek::eek: that stuff smells like crap.
 

·
Registered
Joined
·
4,458 Posts
Discussion Starter · #10 ·
And oh yeah... That slight wobble that I get at low speed every once in a while now appears to be gone :)

If you haven't changed your fork oil. now might be the time to check.
 
1 - 10 of 10 Posts
Top