4Rt Fork Seals

[aussiechris]

Seems like there are problems with both types of forks.

 

Unlike the Tech forks, the problem with the Showa forks is not really the seals.  It is the teflon coating coming away from the top fork bushes and bits of it getting caught under the seal causing it to leak.  Eventually you will have metal to metal contact with the fork tube which won't be good.

 

This is what a faulty bush looks like (and that's not wear and tear):

[andat]

Andat are these Showa forks? I am still having problems with Teflon stripping off the upper fork guide bushes. Factory say there is no problem with Showa forks

[andat]

Yes, Showa. My sons 2015 Repsol. I've got a 2011 and never had any problems

[oz thumper]

Unfortunately, the dealer(s) here in Australia claim not to have heard of any problem.  They've obviously not heard of the internet either.

 

To each individual they will tell you that you are the only one to have had this problem (implying that it is your fault somehow).  Clearly, there is a real problem with the Showa fork bushes from 2015 onwards.  I say onwards because, as Oz Thumper says, the replacement bushes are failing as well.

 

Very disappointing.

 

Hi Chris, A little harsh, I have seen the correspondence between my dealer and the factory in regard to the bush problem. The factory is simply saying that there is no problem with the Showa forks in general and no problem with the bushes in particular.

Thanks for posting the photo, that is exactly how both my bushes were on my Repsol when first stripped. It is clear that there is an issue with the Showa forks and that it did not exist on the pre 2014 machines, the factory attitude is bloody annoying.

 

[oz thumper]

Yes, Showa. My sons 2015 Repsol. I've got a 2011 and never had any problems

 

Thanks for the info. I have also had 4RT's since 2005 without experiencing these bush problems, only normal wear after a couple of years, with the exception of one machine where it was necessary to replace fork tubes due to rock damage.

I would initially have guessed that the problem was caused by not centering the forks on the front axle at the factory causing binding on the fork bushes, however I have now replaced three sets of bushes with the Teflon peeling off and am most careful with correctly centering the axle before torquing up the pinch bolt.

In fact last rebuild I left the spring out so the forks were on full compression before tightening the pinch bolt. (and yes the axle is a free fit in the slider) The forks run freely over their full travel when the bike is lifted onto the stand.

I cant think that it is possible to bore the bush/seal housing in the slider off center from the main slide bore as you would expect these to be bored from a single machine set up, but theoretically this could give this damage pattern.

The fact that the Teflon is peeling off part of the bush and can be removed easily with a tooth brush suggests to me that the issue is the coating application. ( I also note a recent change in the part no. for this component)

 

Once the Teflon has gone there is no further problem with contamination or seal leaks, but I am not happy running the bare copper bush surface on the fork tube.

The fork tubes are expensive, but it is also expensive replacing bushes and oils every couple of  trials.

 

ANYBODY any ideas?? Mr Sunter have you seen this issue in the UK?

 

[oz thumper]

Thanks for the info. I have also had 4RT's since 2005 without experiencing these bush problems, only normal wear after a couple of years, with the exception of one machine where it was necessary to replace fork tubes due to rock damage.

I would initially have guessed that the problem was caused by not centering the forks on the front axle at the factory causing binding on the fork bushes, however I have now replaced three sets of bushes with the Teflon peeling off and am most careful with correctly centering the axle before torquing up the pinch bolt.

In fact last rebuild I left the spring out so the forks were on full compression before tightening the pinch bolt. (and yes the axle is a free fit in the slider) The forks run freely over their full travel when the bike is lifted onto the stand.

I cant think that it is possible to bore the bush/seal housing in the slider off center from the main slide bore as you would expect these to be bored from a single machine set up, but theoretically this could give this damage pattern.

The fact that the Teflon is peeling off part of the bush and can be removed easily with a tooth brush suggests to me that the issue is the coating application. ( I also note a recent change in the part no. for this component)

 

Once the Teflon has gone there is no further problem with contamination or seal leaks, but I am not happy running the bare copper bush surface on the fork tube.

The fork tubes are expensive, but it is also expensive replacing bushes and oils every couple of  trials.

 

ANYBODY any ideas?? Mr Sunter have you seen this issue in the UK?

 

 

ANY IDEAS???

 

[jimmyl]

Three 2015 standard 4rts between us all had weeping fork seals within 2 days to 2 months from new, we replaced all with green skf seals and dust covers at our own expense. Seems a common problem with the original tech fork parts, pathetic really, ours have been superb since, if your toying with the idea of the green skf seals or replacement warranty seals, I'd highly recommend paying for the skf parts. Superb quality

 

Are your SKF seal still going strong?

My second replacement "std" seals and now leaking  - felt like an early F1 drive going down the road yesterday with oil blowing back at me.

Any info from Tech Forks as to why this may be occurring

(bike is 2015 std 260 Mont by the way)

[cornishtwinspring]

Had the skf seals fitted under warranty to my std15 12mnths ago,no problem ever since!!

[jonnyc21]

I would check the seals for particulates, there is a  chance you have some grit or maybe like the showa's the bush coating has flaked and is getting up under the seal?  

 

you could try one of the seal cleaning tools, or might just be better to pull them and check them and the sanctions as well just in case.  2 seals leaking in close or a relatively close interval would make me think something is getting up inside the seals from the inside of the fork.  

 

Hope you figure it out or maybe new SKF's will fix?

[aussiechris]

Hi folks,

I was wondering if anyone has found a suitable replacement top bush for the Showa 39mm forks.  I am gathering quite a collection of faulty bushes as each replacement one I buy fails in the same manner (teflon pealing off and getting under the seal).  The last one I bought lasted just one month (3 rides) and I'm getting quite annoyed about having to replace the bush and seal this often.

I was hoping to find an aftermarket replacement or something off another bike.  The dealer here has contacted the factory about this a number of times and they continue to deny the problem and just say it's not a warranty issue.  I don't want warranty, I just want a bush that lasts like it should.

Some of my bushes:

 

[sportsawyer]

13 hours ago, aussiechris said:

... I was hoping to find an aftermarket replacement or something off another bike.  The dealer here has contacted the factory about this a number of times and they continue to deny the problem and just say it's not a warranty issue.  I don't want warranty, I just want a bush that lasts like it should.

I haven't tried it, but it looks like the earlier bushing from the 2005-2008 4RT and Showa forked 315 models would fit. The sliders and stanchions have the same P.N.s between later and earlier Showa forks, so I'd guess the earlier bushings will work since diameters and depths for bushings would be the same. Race Tech also has bushings with the same dimensions.

Inner Bushing: OD 39mm x Height 20mm x Thick 1mm
  Honda Montesa OEM: 51415-NN4-G01 (2009 & Later)
  Honda Montesa OEM: 51415-NN3-821 (315 & 2005 to 2008)
  Race Tech: FMBI 39201 P

Outer Bushing: ID 39mm x Height 15mm x Thick 2mm
  Honda Montesa OEM: 51414-NN4-G01 (2009 & Later)
  Honda Montesa OEM: 51414-NN3-821 (315 & 2005 to 2008)
  Race Tech: FMBO 39152 P

 

 

[aussiechris]

That's top information - exactly what I was looking for. Thank you Sportsawyer.

Those dimensions look correct.  I see Race Tech also have the correct original NOK BR 2722 seals 39 x 52 x11mm (Race Tech  FSOS 39 P)

My new Montesa bush and seal arrived in the mail today so I will install those now.  However, I will be trying to source the Race Tech parts (just need them to post to Australia) over the coming weeks because I'm sure the Montesa ones will fail soon enough.  I see the Splat Shop are showing the older 51414-NN3-821 part in stock as well.

It's disappointing that even the replacement bushes supplied to the dealers are faulty.  The more correct course of action would be for Montesa to get back to Showa and get them to sort it out.

. 

[jmutiger]

I've seen damage like this from the 2 bushings slamming into each other and climbing on disassembly.  I'd be inclined to think limiting the travel through the cartridge rather than topping out on bushings is the solution.  It might be as simple as setting one fork leg at a different height to use the damper cartridge to restrict overall length rather than the non damped leg 

[oz thumper]

On 23/04/2017 at 5:23 PM, aussiechris said:

Hi folks,

I was wondering if anyone has found a suitable replacement top bush for the Showa 39mm forks.  I am gathering quite a collection of faulty bushes as each replacement one I buy fails in the same manner (teflon pealing off and getting under the seal).  The last one I bought lasted just one month (3 rides) and I'm getting quite annoyed about having to replace the bush and seal this often.

I was hoping to find an aftermarket replacement or something off another bike.  The dealer here has contacted the factory about this a number of times and they continue to deny the problem and just say it's not a warranty issue.  I don't want warranty, I just want a bush that lasts like it should.

Some of my bushes:

 

Hi Chris, Exactly the same as my collection of bushes. I can add that after the first couple of failures I started orienting the bushes with the split to the front of fork leg, so that I could tell the position that the Teflon was peeling from. In my case it is the lower, rear section of the bushes. This eliminates any suggestion of the forks being out of line due to not centering the front axle. (In my case as noted in earlier post I have assembled front axle and fork bridge with the fork legs in full compressed position ) I too am convinced that it is a problem with the coating process because the damage does not extend vertically through the bush as would be caused by any fork tube damage. My dealer has sought advice from the factory but received no response, of the failures that I know of with the Showa forks all occurred after a short period from new and have continued following rebuilds, I have not had this on any of my previous Showa units.

Are the race tech bushes manufactured by them do you know?

I don't think the damage is mechanical from topping out, there are no marks on the edge of the bushing to indicate contact.

[aussiechris]

Thanks Oz.

I don't know who makes the Race Tech bushes, I assumed they were their own aftermarket jobs.  If that was the case I would be happy to try them.  However, I have not managed to find a dealer who could supply the Race Tech parts for reasonable postage rates or at all.  I have tried to register on the Race Tech site so I could order them directly but something broke and I'm now locked out.  Emails to both info@racetech.com and distsales@racetech.com (overseas sales) have gone unanswered.

In desperation, I have ordered a pair of bushes and seals from the Splat Shop in the UK.  They were showing the bushes under the old Honda part number so I thought I'd take a chance on them.  They'll be another week or two away.

The new bush and seal I installed the other week only lasted one ride.  That same fork is leaking again but not too bad.  I have a competition this weekend so it will have to do.

Assuming it is a manufacturing fault (and I think it is), it's unfortunate that there appears no way for dealers or customers to tell if new stock is good or bad.  The dealer seemed to indicate that the factory are just saying it's not a warranty issue.  But I'm sure we're all happy to pay for new bushes ourselves but would like some certainty that they are good ones.  I'll also be checking the fork tube to ensure it's not bent next time it's apart.  But it was sliding freely last time I re-built it.  The teflon just doesn't seem to be stuck properly to the metal.  I've had numerous bikes with huge mileage and never had a problem like this - and never gone close to even wearing out a bush.

Other than that, the bike is great.  And I still think nothing comes close to the Showa suspension both front and rear.