fork oil and engine oil

[Solon]

I'm about to perform my first oil change on a steamer, and my first fork job ever.
I have searched the manuals but I didn't find an oil viscosity recommendation. I want to know what viscosity I should use and how much oil it will take.
The same about fork -  how much oil is needed for servicing, and will I need anything else besides the rubber seals?

[Mustang]

the engine needs 10w40 , 20w50 works as well as 5w40

the suspension needs 10 wt  suspension oil not motor oil , there is a difference. 15 wt will stiffen it up some.

[Solon]

Great, thanks. And quantity - will it take 4 full liters in the engine?
For the fork should i get 1 or two liters?

[threepot]

Engine takes 3.75 ltrs. As for forks,you should measure from top of fork tube,off bike,spring out and compressed. Should be 130mm. I,ve just checked the fluid on mine..easy on Steamer,without taking forks off.  Drained fluid,looked/smelt fresh..put back in! Measured 620ml in each leg. Dont know if qty is right(my Daytona takes about 450 and its a shorter leg) My forks work nice on that qty.  Apparently ATF works ok? I've got a gall in the shed somewhere,will try that soon.

[sweller]

I,ve just checked the fluid on mine..easy on Steamer,without taking forks off.  Drained fluid,looked/smelt fresh..put back in! Measured 620ml in each leg.

How did you check and drain the fluids without taking the fork off? 

620 sounds a lot.

Apparently ATF works ok? I've got a gall in the shed somewhere,will try that soon.

ATF is/was commonplace for use as fork oil in a number of older bikes I've owned - which shouldn't come as a surprise as it does very similar job in a transmission or power steering - hydraulic fluid maintaining consistent viscosity under use and temp changes with good anti-foaming properties.

I think ATF comes in at about 10wt - the advantage of specific fork oil is you know what weight you're dealing with.  TBH, I would just buy fork oil.

[Solon]

Engine takes 3.75 ltrs. [...] Measured 620ml in each leg. [...]

Thanks. So I must get two liters of fork oil. There is no motorcycle shop in my town and I have to order via the internet. That's why I needed the info, it would be annoying to be left with the fork broken down with not enough oil and to have two wait 2 or 3 days till another liter of fork oil comes by post.

[threepot]

630ml sounds about right.. http://www.louis.de/index.php?topic=bikedb&CONTENT=technik&typ_id=709EN%2F06&lang=en
My front suspension works fine with that qty. It may not be exactly right,but I'm not worried too much. Next time the fr wheel is off,I'll check. Engine oil would probably work ok..10w,got anti foam agents. There are rubber seals inside your engines. How much is fork oil..£10/13 ltr??!!

[Solon]

[...] How much is fork oil..£10/13 ltr??!!

Yup. Somewhere around that figure. It's not a fortune, but I don't want to order 1 extra liter if it's not absolutely necessary, what will I do with it if it proves unnecessary, lube door hinges ?

It's a bit unclear to me if there's any real difference between (cheap) engine oil and fork oil - besides marketing and need for extra cash from the producer. ATF is also cheap - 3 or 4 Euros.

[fishnbiker]

First item, get a shop manual. Usually available on Ebay or Amazon.

For the forks, you will need around 630~650 ml per side. Adjusting the level has a small effect on the way it performs, but this range has always worked for me (now on year 17 with Felix). Any oil not used can wait for the next change. I do mine every winter or more. I ride mostly muddy or dusty gravel, so more maintenance needed on everything.

As previously said, 10w is a normal viscosity. I stiffen it a bit with a 50/50 blend of 10w & 15w, sort of 12.5w.

Some care must be taken removing the fork cap, as it's preloaded on the spring. Also on refit, you would do best with a socket on an extension to push the cap down while screwing it on. Drain cap is small screw at bottom of lower leg. Be notified that the oil can spill out quickly, some distance, so hold the pick-up container closely at first. If only on a side stand, use jacks or blocks under the foot pegs to keep the bike vertical & forks from collapsing when removing the top caps. Or, finish one side before starting the other.

If you have a thin metal tube inside about 4" long you can replace it with a piece of PVC plastic water pipe an inch or two longer for more preload for a more robust response. Search forks & springs in the archives for more details.

[Solon]

Good info, thanks for sharing!