?Fork oil

 

The manual for my 1979 Honda CB 650 simply calls for using ATF in the front
forks, no specs given. Can someone translate 1979-speak  "ATF" to the kinds
of ATF available nowadays to choose from? Thanks,

frog

 


The reason for using ATF in those days was two-fold.

The first reason was that it didn't entrain air (foam up) during rapid
stroking, which caused inconsistent damping over rough surfaces.

The other reason was that ATF used to contain whale oil as a friction
modifier.

Importation of whale oil was banned later.

ATF might be about 2.5 weight or 5 weight and you'd probably be better
off using
a light weight fork oil intended for motorcycles.

 


Not true, not true at all...


Maybe in the 50's you stupid git.


iirc that was in the 50's.


There is little consistance in weights of atf. That's a fact that you
obviously aren't aware of.

Then again considering that YOU Krusty Kritter don't know much about
anything you can't wiki it's not surprising.

 


That is because nobody was making fork specific oils at the time. I'd
suggest start with something in the 10wt range and working from there.
Most likely you'll end up with a heavier oil as the only way to adjust
your front suspension is with the oil weight and the springs.

http://www.google.com/search?sourceid=navclient&aq=0&oq=motorcycle+fo=
rk+oi&ie=UTF-8&rlz=1T4GGLL_enUS374US374&q=motorcycle+fork+oil

is good start. I also suggest you look up some type specific web pages
for your CB650.

I've GL1000 of similar vintage and am running 10wt, may bump up to
12wt or even 15wt but that is becasue I don't piddle along...I push
that old frame and suspension technology to it's limits.

 

Thanks for the info, but that brings it back around to my question about
what did Honda mean when they used the term "ATF" in 1979. You can read
hundreds of well-versed opinions from here and from Googling, many by oil
experts (as in "Amsoil 5wt. is less viscous than other 5wts". HUH?). If
going from 5wt. to 15wt. makes that much difference (or not) it's all
guessing unless you know how your bike handles with one or the other.

I would like to change my fork oil to the factory recommendation to start
with. Then if it needs a little heavier or lighter I can have an optimum
baseline to judge from.

Does anyone know what Honda meant by "use ATF" back in '79? You know, like
was it a Dexron thing, or some other standard?

Thanks,  frog



That is because nobody was making fork specific oils at the time. I'd
suggest start with something in the 10wt range and working from there.
Most likely you'll end up with a heavier oil as the only way to adjust
your front suspension is with the oil weight and the springs.

http://www.google.com/search?sourceid=navclient&aq=0&oq=motorcycle+fork+oi&ie=UTF-8&rlz=1T4GGLL_enUS374US374&q=motorcycle+fork+oil

is good start. I also suggest you look up some type specific web pages
for your CB650.

I've GL1000 of similar vintage and am running 10wt, may bump up to
12wt or even 15wt but that is becasue I don't piddle along...I push
that old frame and suspension technology to it's limits.