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Leaking Fork Seal


Mr Toad

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Mr Toad

Noticed this morning that one of my fork seals is leaking slightly.

 

Looks like a job for the weekend providing I can get a pair of seals from Honda. 

 

What's the consensus regarding the oil, replace like for like or change the weight? If it's change then what weight oil are people using?

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rjp996

i used the Silkolene pro rsf fork oil 7.5 wt when i changed mine - same viscosity as the honda oem 10Wt

Previously I used the Repsol 10Wt

Both seem to be the same when on the road

 

I also got a cheap fork seal driver (but also put the old seal on top as well so the seal driver was driving the old seal that was then pushing the new seal down - found easier.

I also used a cheap fork oil level syringe from 'laser' to set the correct oil level - 

 

 

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rjp996

Point to note - when separating the forks - both mine were hard to slide apart as the bearing on the end of the leg slides over the other end. The bearing has a teflon coating that can get damaged and I had to order and replace one of mine (simple to do, but took a day to get in).

 

Also the hex bolt at the bottom of the leg - taking it out, the internal piston can spin - to get around this, after emptying the oil, compress the fork so the spring it pushed down to stop it spinning.

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embee

If the internal damper rod does turn with the capscrew in the bottom, the usual recommended technique is to chamfer the end of a wooden broomstick (or dowel if you prefer a technical word) to a taper and tap it into the hole in the top end of the rod to hold it. Sounds primitive but it works well without risking any damage.

Oh, and don't forget to take the wire circlip out first!

Edited by embee
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rjp996

im thinking the next time i service the forks and change the oil, i may try a lighter - less viscous oil and see if it improves the high speed damping ?

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embee

Worth a try, it's the cheapest mod you can do.

In case you or anyone else haven't come across this, there is a table of viscosities and "VI" index for a whole range of commercially available oils here

http://peterverdone.com/wiki/?title=Suspension_Fluid

The Fuchs/Silkolene RSF (formerly called PRO RSF and now called Maintain RSF) oils have generally high VI which is a desirable thing, less change in viscosity with temperature. You could maybe try the 5W version, or a mixture.

I use the RSF 7.5W but I have emulators fitted so not really relevant to unmolested forks.

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Mr Toad

Fork seals replaced. 

 

I ordered a pair yesterday from Weemoto and they arrived this morning so I got stuck in and 2 hours later both seals have been replaced. No drama, all good.

 

A pair of Honda seals £25.41 each and not in stock, well there's a surprise. A pair from Weemoto for £11.75 delivered, a much better price. 

 

I examined the original seal and fork leg but can find no reason for the failure other than it just went pop. No rust, pitting of anything on the fork legs that might have damaged it and the seal looked to be in good shape except for the leaking. The OEM seal only lasted for 7000 miles but hey ho stuff fails, all good now.

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2 minutes ago, Mr Toad said:

Fork seals replaced. 

 

I ordered a pair yesterday from Weemoto and they arrived this morning so I got stuck in and 2 hours later both seals have been replaced. No drama, all good.

 

A pair of Honda seals £25.41 each and not in stock, well there's a surprise. A pair from Weemoto for £11.75 delivered, a much better price. 

 

I examined the original seal and fork leg but can find no reason for the failure other than it just went pop. No rust, pitting of anything on the fork legs that might have damaged it and the seal looked to be in good shape except for the leaking. The OEM seal only lasted for 7000 miles but hey ho stuff fails, all good now.

 

I am impressed by your sanguinity.  I can't help thinking that Honda should be forking out here (oh, God, did I really write that?).

  • Haha 1
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On 31/07/2018 at 23:50, Mr Toad said:

Noticed this morning that one of my fork seals is leaking slightly.

 

Looks like a job for the weekend providing I can get a pair of seals from Honda. 

 

What's the consensus regarding the oil, replace like for like or change the weight? If it's change then what weight oil are people using?

 

Left hand seal?

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Tonyj

sometimes shit can get between the seal and leg so i always try the film trick first. the ktm forks have a habit of leaking when just left on side stand . these are the upside down ones so it shows quicker

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Mr Toad
14 hours ago, Tex said:

 

Left hand seal?

 

Yes Simon, do you know something that I don't? 

 

Not that I'd be surprised that you do. :) 

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Mr Toad
14 hours ago, DMB said:

 

I am impressed by your sanguinity.  I can't help thinking that Honda should be forking out here (oh, God, did I really write that?).

 

Given that the bike is three years old I wouldn't expect Honda to fork out, yes we did both write that. :) 

 

12 hours ago, Tonyj said:

sometimes shit can get between the seal and leg so i always try the film trick first. the ktm forks have a habit of leaking when just left on side stand . these are the upside down ones so it shows quicker

 

I did have a good look at them both and also felt for any pitting or debris on the legs but found nothing. It wasn't a job I could ignore and put on a fix later list either as it was much more than just a thin film of oil on the leg. When pushing down on the bars I could see the oil coming out.

 

On 8/1/2018 at 12:05, embee said:

If the internal damper rod does turn with the capscrew in the bottom, the usual recommended technique is to chamfer the end of a wooden broomstick (or dowel if you prefer a technical word) to a taper and tap it into the hole in the top end of the rod to hold it. Sounds primitive but it works well without risking any damage.

Oh, and don't forget to take the wire circlip out first!

 

Fortunately I had no problem getting the bottom bolts out, unlike some older bikes in the past. I used a T handle hex wrench with a small ring spanner on the shaft and they came undone easily. If that had failed I have a compressor and windy gun that would have shifted it.

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Guest machinman
3 minutes ago, Mr Toad said:

 

Given that the bike is three years old I wouldn't expect Honda to fork out, yes we did both write that. :) 

 

 

I did have a good look at them both and also felt for any pitting or debris on the legs but found nothing. It wasn't a job I could ignore and put on a fix later list either as it was much more than just a thin film of oil on the leg. When pushing down on the bars I could see the oil coming out.

 

 

Fortunately I had no problem getting the bottom bolts out, unlike some older bikes in the past. I used a T handle hex wrench with a small ring spanner on the shaft and they came undone easily. If that had failed I have a compressor and windy gun that would have shifted it.

Im doing mine today, changing the stanchion and both bushings. Fingers crossed for no dramas.

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Mr Toad
1 minute ago, machinman said:

Im doing mine today, changing the stanchion and both bushings. Fingers crossed for no dramas.

 

Clear yourself some workspace and have plenty of paper towels and rags handy as it can get very messy if you're not careful. 

 

The only thing I have left to do is dispose of the old oil, it's currently sitting on the bench in a bowl. I shall sort out a suitably sized container today and take it to the oil recycling container at the dump.

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Guest machinman
5 minutes ago, Mr Toad said:

 

Clear yourself some workspace and have plenty of paper towels and rags handy as it can get very messy if you're not careful. 

 

The only thing I have left to do is dispose of the old oil, it's currently sitting on the bench in a bowl. I shall sort out a suitably sized container today and take it to the oil recycling container at the dump.

Can i ask what weight you used and how much.

Cheers.

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Mr Toad
3 minutes ago, machinman said:

Can i ask what weight you used and how much.

Cheers.

 

Honda recommend 10W which is fortunate as that's what I had on the shelf. According to the Honda service manual the X takes 514cc and the S takes 518cc +/- 2.5cc

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Mr Toad
5 hours ago, machinman said:

Cheers, its a bit of a pain that its just over a litre.

 

Exactly, I was fortunate in that I had part of a 1 litre bottle and another unopened bottle. 

 

That said I'd go for 500cc in each fork and either leave it at that or put 20cc of the same weight engine oil in to make it up. 

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embee

I'd always recommend setting it by height rather than volume.

 

Recently did a friend's Deau 700, and we couldn't find the height value so filled by volume. Suspension was a bit harsh on bigger bumps. Eventually found the level value and the volume method had given nearly 20mm extra height. Took out the extra down to the recommended level and all was well.

Ultimately the level is a bit arbitrary, it just varies the air spring effect approaching full compression. I set mine a good 30mm lower than the book value with the suspension mods I've done to get the right feel (for me). It would be fine to put 500ml in each side and see what it felt like if you wanted. You can top up as necessary.

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Dunnster

Recently changed my fork oil, did it by air gap and a litre bottle was enough split between the two legs. I'd bought two 1 litre bottles but only needed the one of them. 

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