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I’ve been doing some reading regarding “fork improvements” — there are many threads, and much good information — but I’ve got to say, the more I read, the more my head spins ….

“Fork emulators” — “Rider sag” — “Longer springs” — “Spacers” — “The broom stick method” (whatever that means) — the list of possibilities is endless

Given that my ’98 is fortunate enough to have a set of “proper forks”, (eg the ones with drain holes at the bottom), it occurs to me that changing the oil should be a relatively simple affair, involving none of the above “complications” — get the old stuff out, and re-fill with the desired amount

Sounds simple enough ….

I know that following the manual on this is futile — and would ask the others on here on what personal experiences with viscosity and volume they have had (200lb rider — wet)

Remember, this is the bike that goes into reverse when the perceived threat of a socket is presented, so for the bikes sake (and mine) — I just want to “KISS” this

How much — and what weight ?

(And if I could keep the “clack”, it would be appreciated) ………. :)
 

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Clack seems to disappear and rebound dampening appears if oil level is raised higher than ~130mm as measured from top of vertical, compressed, empty fork tube. I use 10w oil after first flushing out old aluma-sludge with cheap automatic transmission fluid ( ATF). A few more ml of oil will firm things up nicely for a 200 lb wet rider. I set mine at ~128mm but living in desert climates I am rarely wet.
 

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Discussion Starter #3
Now there you go again - with the “top vertical compressed” bit - and the “130mm”

All I need to know, is how much to pour into the top, and what viscosity

Assume I don’t have any spare broomsticks (just for a moment) —nor a laser range finder to poke down the top to find the 130mm sweet spot

Not even an oil finding Hamster to report back to me (complete with little LED headlight) attached to a piece of string

No gimmicks, no gadgets, no rodents — just me, an empty fork, a bottle of oil, (and a worried looking bike)

And regarding the original Yamaha OEM “clack” — as long as it’s barely noticeable, I’m sure that’ll be fine. Although I have always regarded the “clack” as an indicator that the forks where working to within Yamaha specifications, my dentist disagrees. He seems to think it’s my teeth- the Doc says it’s likely to be my nuts — and frankly, it’s confusing, and costing me a fortune

And what’s with this “rebound” bit — the TW forks rebound? — Why wasn’t I told of this ?

I thought that was a myth ……
 

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Purple you desire a simple cc or oz measurement to accomplish what is variable goals. But that being said it would be great to have a table of oz’s or cc’s of fork oil to say be at 130 mm from the top for xxx-xxx lbs of rider. 128 mm, 125 mm etc. I don’t know if the capacity of the forks changed when they removed the plug and if this would work for all years.

Ok who is manic enough and has drain holes in their forks to add and measure different levels to come up with this table? Any takers?

If you have the bucks the best option seems like procycles kit of progressive springs and emulator with recommended oil based on your rider weight.

There is an easy way to measure the depth of the oil just use a pencil mark a line on it near the top stick it into the hole of the fork up to the line and then measure the from wet spot to the line bingo your fork oil depth. Just make sure what ever you put into the forks to measure with is longer than the length you want to measure. Lol. Of course you have to remove the cap and springs and then compress the fork tubes. Supporting the front of the bike while removing the springs, etc. it is not as complicated as it sounds.
 

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Discussion Starter #5
So – in summary – we have absolutely no idea on how much oil should go into a TW fork leg, other than to employ the “diving Hamster on a bit of string” method

This pretty much confirms my own reading of the situation – but surely we have had to address this before ……
 

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This is not the first time someone has shouted down the well seeking a simple volumetric response to no avail. Sorry Purple, I knew your goal but was too embarrassed to admit to my not measuring by volume last time I forked up my TW. I lack a proper graduated cylinder but suppose I could always weigh before and after and then convert to milliliters next time. What is the specific gravity of Bel-Ray 10W fork oil anyways?:p
 

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Pour a 8 ounce bottle of fork oil in each fork, test, drain excess from plugs if needed. ?? ;)
 

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All I need to know, is how much to pour into the top, and what viscosity
……
Sorry Purple, it just doesn't work that way. If I told you to pour exactly 385 milliliters of 10 Wt. Fork oil into each fork to arrive at a measurement of 130 mm, I would be wrong. Since you have to remove the fork caps and drain to add new oil, you have already done 3/4 of the job. All you have to do now is take the spacer and springs out, close the drain bolt, add several ounces of ATF and exercise the forks a few dozen times. Lather, rinse, repeat. This step is important to get rid of the sludge at the bottom of the forks. It helps to drain into a glass container so you can see the ATF clear up after a couple of repetitions.
Then compress the forks all the way, add about 8 oz. of fresh 10 wt. fork oil and using a 1/8 inch wood dowel available at most model stores or even hardware stores, make a mark from one end at 130 mm and put that mark at the top of the fork tube. Add oil until the bottom of the dowel gets wet, just a few cc at a time. Yes, this does take time but if you want to do it right you can't skip this step. The forks are quite sensitive to small increments of oil, and the level is the way to measure accurately.
For your weight, the 130 mm level is very close to perfect. When it's there, put the springs and spacers back in, EXTEND the forks all the way and put the caps back on. It's worth doing right. I did this 11,000 miles ago and the forks have worked just fine ever since. It's now about time to change out the oil again, and I will use the exact same procedure again.
 

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I always wanted a no brainer oil volume to just dump into my forks. One day I was watching a video, from a Pennsylvania guy that goes by "Smightification" on YouTube, showing the installation of Procycle higher rate fork springs that called for 8oz. of oil per the installation instructions. And later reading through many fork oil threads I saw that lizardbreath suggested the use of ATF fluid as an acceptable alternative to 10w fork oil. So when I flushed mine that's what I used. 8oz. of mercon/dextron tranny fluid in each tube has worked fantastically for me on road and off. 10w fork oil of any brand would be fine but the viscosity of the mercon/dextron is excellent and it's cheap. I weigh 200lbs. for reference.
 

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I went to the dollar store and bought 2 clear plastic catsup/mustard squirt bottles. 12.5 ounce according to the label. then I just split the 16 oz bottle of fork oil equally. The squirt caps made it easy and clean. I didn't measure, but the oil level looked to be around 5 to 6 inches from the top of each compressed leg. I had to drill out 4 - 10mm holes in the damping rods to add the emulators, so there's no going back. Added the heavy springs and didn't need any spacer for 1/2" of preload. It's too expensive, but easily the most beneficial upgrade I've done.
 

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Discussion Starter #13
So the consensus of opinion, is that if you lob 8 (US) fl oz down each leg, you’re about right – (I figure there’s always a few bits left over when you do this sort of thing, so the 0.05 will be residue)

Then, you get the Hamster set up, dangle him down the leg, and when he tugs on the string after 135mm, you’re good to go

Presumably, the “135mm” bit is a precaution against someone mixing up USA fl oz with Imperial, having your glasses steamed up at the time, or not quite being quick enough to retrieve the Hamster – although at that point, if you subtract the wet from the dry, it’s all good, but you might need a new Hamster

Never in the history of human endeavour, have so few conspired to take something so simple, and complicate it beyond reason for so many – it reminds of me of the invention of the “variable potentiometer” - a device used in many applications, and also known by its common name – the “Volume Knob”

As to “Gog Garages”, they built them to last in them days. Note the simple four piece construction, the roof angled back to keep the rain off – the delicate way the front is suspended – we could have taught Ikea a few things about flat pack construction back then ……..
 

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As a founding member of the ASPCBH (American Society for the Prevention of Cruelty to British Hamsters) I feel compelled to renew my offer from earlier this year of free fork oil level dipsticks.

http://tw200forum.com/forum/technical-help/20404-free-almost-fork-oil-level-dipsticks.html



So, Purple (and any other forum members), please save your hamsters and send me your address and I will send you a free fork oil dipstick.

Remember - "Hamster Lives Matter Too!"
 

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The KTM guy (racer, tuner, regional champion bla bla bla) personally did my front fork suspension and rear one by modifying it with N2O and oil (only rear) making it with a valve since the back one can't be refilled actually... so he is very prepared
he put 300ml of oil in both suspension in the front, 300 right and 300 left, that's what I can say
 

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As a founding member of the ASPCBH (American Society for the Prevention of Cruelty to British Hamsters) I feel compelled to renew my offer from earlier this year of free fork oil level dipsticks.

http://tw200forum.com/forum/technical-help/20404-free-almost-fork-oil-level-dipsticks.html



So, Purple (and any other forum members), please save your hamsters and send me your address and I will send you a free fork oil dipstick.

Remember - "Hamster Lives Matter Too!"
I had not seen this tool before. Thanks for sharing this again. Genius idea. Very nice of you to share this with us. Does this pretty much work the same on all years? My beater is a 2001. PM sent. Cheers buddy
 

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I had not seen this tool before. Thanks for sharing this again. Genius idea. Very nice of you to share this with us. Does this pretty much work the same on all years? My beater is a 2001. PM sent. Cheers buddy
Yes Badger, the forks are pretty much the same for all model years. Yamaha did do away with the drain screws on the lower fork legs sometime around 2001. If your bike still has these drain screws, consider yourself lucky!

I'll get a dipstick in the mail to you right away, thanks!
 
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