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Post Info TOPIC: Forks - replacing the fork oil


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Forks - replacing the fork oil
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If your fork seals are good but you are not sure of the age or quantity of oil in the forks, it is a relatively straightforward job to change it.

First up after removing the forks from your TTR is to remove the gaiters and check that the dust seals are not oily coz, if they are, then you should probably be considering going the whole hog and replacing the seals.

Otherwise. clean up the forks, check the stanchions are straight and their chrome is good where it touches on the seals. 

Then clamp the leg into the yokes to stop the stanchion turning when undoing the cap nut but BEFORE you start to do that, let any air pressure off through the Schrader valve by taking off the cover and depressing the valve core stem. This one had some air in and, if you don't do this, you may have an oily mess as the cap is loosened.

Fork oil change 1.jpg

 

The cap comes off easily with a 30mm socket.

Fork oil change 2.jpg

 

It is then a case of putting down some newspaper (I seem to have problems with draining fork oil and usually end up with a few ceecees in my shoes disbelief ) and draining the oil off into a suitable container.

Draining fork oil.jpg 

Leave the forks to drain and measure what comes out to see how it compares to the recommended 550cc! 

I managed to drain nearly 550cc of oil out of each leg which was a good sign. The oil from one fork was pretty clean so maybe an oil seal had been changed at some stage.  The oil from the other was a bit manky indicating it was probably the original.

Fork oil change 4.jpg

 

Now dismantle the forks further to properly drain and flush them and allow you to adjust the oil level as per the manual.

This involved pushing down the spring collar to be able to get a spanner in and then taking off the cap.

Fork oil change 5.jpg

 

Once the spring is out, rinse out the forks with clean fork oil and drain them again. Then pour in 550cc of fresh Silkolene fork oil. I used 5 weight as the original oil is very thin for a heavyweight like me and the thicker oil improves the damping. What is slightly annoying is that 2 x 550cc = 1.1 litre and the fork oil comes in 1 litre bottles cry

Fork oil change 6.jpg

 

I use a screwdriver with a zip tie set at 130cm (from top of stanchion with stanchion and damper rod fully compressed and spring out) to check and adjust the oil level. The red wire is there to feed the spring over at a later stage. That said, I found it was too thick and had to resort to thin wire instead.

Fork oil change 7.jpg

 

Then pump the inner rod as per the manual to get the air out and within a few strokes you feel quite a resistance indicating the oil has reached the right places biggrin

I fed the spring, collar and and spring seats over the damper rod and pulled the rod up through with the wire. It was then just a case of reversing the dismantling process and screwing the cap onto the rod whilst holding the nut with a spanner. Then lifting the inner tube up over the spring and screwing the cap down into it.

A bit of a clean up and the forks are read for a new set of gaiters and fitting to the yokes wink

Fork oil change 9.jpg

 

In conclusion, it is a fairly straightforward job to refresh fork oil without the palaver involved with changing seals.

Brian



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Fork.gif

 

 

What are you attaching the wire to? part Number here: 12?

-- Edited by Webike4fun on Tuesday 21st of April 2015 05:06:21 PM



-- Edited by Webike4fun on Tuesday 21st of April 2015 05:35:11 PM

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Yep - that's the one biggrin

It'll be obvious when you get to do it I promise!



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LOL Maybe 40lb mono fishing line will work too!


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Wow that went really well! Big thanks for tutorial! Done in under 1 hour too. Forks feel smooooooof now! Old oil was really dirty original no doubt. One more question and I'll also post to board: the rebound adjustment screw at the bottom if the fork clicks really well on one side and really is none exists an to t the other? Now original owner never adjusted so I'm thinking if I keep playing with it a bit it will come to life but any thoughts?

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I performed the oil change last week, I fashioned a holder for the rod out of a coat hanger, worked nicely. It did become clear what to do during reassembly.


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WHATS RECOMENDED SETTINGS FOR CLICKERS AS STANDARD

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JOHNYBOY wrote:

WHATS RECOMENDED SETTINGS FOR CLICKERS AS STANDARD


 Settings here



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Just done the fork oil on my one.Stuck 5w in it from halfords. Even though I put 550cc in each leg I still had to suck some out to get the correct level.I use one of those fork level tools. Forks feel a lot better now...

One thing Brian I didnt use anything to secure the damper rod from falling down inside the fork leg. I managed to hold everything together and do it all up fine..I did lose the damper rod down the spring a couple of times but I used a strong extendable magnet to put it back up again.Works a treat...



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This is a surprisingly easy job. Did both forks an about an hour. Thanks for the instructions.

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i have used brians guide and its great , one of those jobs that's a mystery or put off for another day  but when you have a go its pretty straight forward .

 

how bad is the smell of the stuff Mr Yamaha puts in from new  when it comes out biggrin



-- Edited by ttboof on Saturday 18th of April 2020 11:50:47 PM

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I must be doing someting stupid I guess. I removed all the air and then tried to get the 30mm top caps off. Both turn OK but at the last bit of thread just pop back down again as if something is pulling the caps down. Anyone tell me what mistake I am making...I am guessing a bit of a "doh" moment coming up.....



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Falkie wrote:

I must be doing someting stupid I guess. I removed all the air and then tried to get the 30mm top caps off. Both turn OK but at the last bit of thread just pop back down again as if something is pulling the caps down. Anyone tell me what mistake I am making...I am guessing a bit of a "doh" moment coming up.....


 From memory the caps are attached to the internal dampers .you have to squeeze an open ended spanner in under the cap and loosen  the lock nut then the cap will spin off the internal rod a bit fiddly the first time .

Can be a bit fiddly putting it back together I use a bit of wire to hold the centre rod up while you got the cap back on 

 



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