Author Topic: fork oil seal....up or down?.... (Read 2818 times)

jaguar · « **on:** November 05, 2007, 07:05:58 AM »

i know its a dump question and i should know better but does the open side( the side with the spring) face inside or outside. i think it faces in and the numbers face out(so you can read the seal numbers) but i just can remember. also before you get on my case about the manual i have it in my hand and its not clear.
thanks
its also for a CL125s

SteveD CB500F · « **Reply #1 on:** November 05, 2007, 07:08:15 AM »

Numbers up.
Spring down.

jaguar · « **Reply #2 on:** November 05, 2007, 05:18:52 PM »

thanks

also the manual says to use 10w40. can i use any motor oil or does anyone have a recomendation?

seaweb11 · « **Reply #3 on:** November 05, 2007, 05:23:16 PM »

fork oil

TwoTired · « **Reply #4 on:** November 05, 2007, 10:11:51 PM »

You want something that won't whip into a froth. Anti-foam agents are found in Fork oil and auto trans fluid. I you want a viscosity other than 7-10W (ATF) then use a fork oil in a grade that suits you.

Cheers,

jaguar · « **Reply #5 on:** November 05, 2007, 10:14:12 PM »

i know its a dump question but where do i get fork oil? the manual said SAE 10w-30(not 40) so i need that weight in fork oil and not normal motor oil?

SteveD CB500F · « **Reply #6 on:** November 06, 2007, 01:53:49 AM »

Any bike shop or decent auto factor will sell propriety fork oil. As TT says, it's formulated differently from engine oil (it doesn't get hot for a start!).

It's available in different grades: 20W, 30W 40W etc.

I use 30W as it's the middle grade.

TwoTired · « **Reply #7 on:** November 06, 2007, 09:30:17 AM »

Multi-grade oils behave as the lower weight when cold and the higher weight when hot. Forks aren't heated by combustion temps, so a 10W-30 motor oil is going to behave like 10 weight fork oil, except for the foaming on washboard roads.

A thicker oil in the forks will make the front suspension stiffer and transfer more road irregularities to the handle bars. Some like it that way.
Fork oil is available at motorcycle shops, or google "Fork oil".

cheers,

Bob Wessner · « **Reply #8 on:** November 06, 2007, 10:33:54 AM »

I use 10w30 motor oil in mine, no problems. Even as TT said, in the cold it behaves at the 10w viscosity, but in the 40 degree temp. range it still is noticably stiffer. But then, so are the tires.

jaguar · « **Reply #9 on:** November 07, 2007, 03:41:10 AM »

well i dont understand why the manual calls for a split weight then...

Bob Wessner · « **Reply #10 on:** November 07, 2007, 03:54:18 AM »

Quote from: jaguar on November 07, 2007, 03:41:10 AM

well i don't understand why the manual calls for a split weight then...

As TT suggests, because of the temperature variations. Though I 'notice' a stiffening of the suspension when cold, I'm sure it would be substantially worse if, for example I were to use straight 30 weight. Conversely, it would be soft with straight 10 weight at say, 90F.

Tim. · « **Reply #11 on:** November 07, 2007, 06:20:16 AM »

Don't lots of people run ATF in their forks? I seem to recall dumping it into my 500K forks 10 years ago. Today I'd go out and buy fork oil in the recommended weight, but I do recall running ATF and even reading it in some manuals.

Bob Wessner · « **Reply #12 on:** November 07, 2007, 06:29:41 AM »

I'm not sure, but I seem to recall there were fork modifications to later models with changes to the recommended fluid to be used. For my K0, manual says 10w30 oil.

TwoTired · « **Reply #13 on:** November 07, 2007, 09:27:37 AM »

Quote from: tintin on November 07, 2007, 06:20:16 AM

Don't lots of people run ATF in their forks? I seem to recall dumping it into my 500K forks 10 years ago. Today I'd go out and buy fork oil in the recommended weight, but I do recall running ATF and even reading it in some manuals.

That's a good point. I believe there are also additives in both ATF and dedicated fork oil that helps keep the seals from hardening, prolonging their life. I've used ATF on owners manual recommendations, too. 74 Cb550 manual states ATF, as does the 72 Cb500, and 77 CB750F manuals.

As stated before, ATF and fork oil have anti foaming characteristics, which I feel are important to shock operation. Not all motor oils have this property. Air bubbles will flow through the shock valve orifices much faster than a more viscous fluid. The advantage for fork oil is that you can tailor the viscosity to your riding needs. ATF seems to vary somewhat between 7 and 10W. I happen to prefer 15W in my CB550 forks. Can't get that weight in ATF at any of my sources.

Cheers,

Bob Wessner · « **Reply #14 on:** November 07, 2007, 10:25:09 AM »

I guess I would be surprised if any modern motor oil formulation didn't contain anti-foaming agents of some kind.

TwoTired · « **Reply #15 on:** November 07, 2007, 10:59:43 AM »

Quote from: Bob Wessner on November 07, 2007, 10:25:09 AM

I guess I would be surprised if any modern motor oil formulation didn't contain anti-foaming agents of some kind.

You just can't help yourself with steering discussions into an oil debate, can you Bob? Are you a religious man?

Cheers,

Bob Wessner · « **Reply #16 on:** November 07, 2007, 11:05:18 AM »

Hardly.

jaguar · « **Reply #17 on:** November 07, 2007, 03:02:45 PM »

well do they even make split weight FORK oil? if not im just gunna use moble one and see

mark · « **Reply #18 on:** November 07, 2007, 06:50:16 PM »

FWIW... the general maintenance part of my '70s Clymer calls for ATF in the CB350 and 10W30 oil in the CB400/500/550..... The 'Performance Improvements' section calls for Torco 20-weight fork oil in all.

Happy trails.

bryanj · « **Reply #19 on:** November 07, 2007, 09:55:24 PM »

specific fork oil didnt exist when the books were written so the manufacturers compromised, now it does so use it"

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Author Topic: fork oil seal....up or down?.... (Read 2818 times)