Front Fork Oil Leaks

[Noel Hynes 28]

I purchased a 2015 Honda NC750DCT last year with 3,200 miles on the clock. As I bought it later in the year I did not do much riding in 2019 and with Covid- only recently clocked up some miles.

 

I have now noticed both front fork seals are leaking- one is particularly bad and significant amounts of oil falling onto the ground. I read on the forum of this being a problem with the NC750- I did not notice it until recently after a few runs. To see this on such a low mileage bike is not what I expected for the price I paid. I noticed a while back that there was some oil on the fork and a fellow biker highlighted it at a cafe stop a few weeks back. I realise that work will have to be done on both forks- and wondering if it would be a difficult job to carry out.

 

My questions are:

 

1. Has anyone attempted to do fork seal replacements on the front forks ?

2. Was it a difficult job to do ?

3. Can you advise where you bought new seals

4. Is it a job you think could be tackled with some DIY experience.

 

Any thoughts/comments would be appreciated.

 

Thank you in anticipation.

 

[Mark8arker 527]

If you have centre stand its quite easy jod to do. Lots videos online. Take a look at one. Replaced mine when fitted yss fork kit to my  NC. Parts for my NC from local Honda dealer, Fowlers web shop & Wemoto.

[MatBin 5,081]

Oil seals can dry out, especially suspension seals if the bike isn't getting used, suspension movement lubricates the seals and keeps them flexible.

I would check you don't have any pitting on the fork leg stanchions whilst they are apart. Also check rear suspension unit and linkages for the same reason.

Edited August 9, 2020 by MatBin

[RC166 694]

It’s worth having a go a cleaning any muck out around the seals without taking any thing apart. Have an internet search on front fork DIY oil seal cleaning tool or similar. I followed instructions and made one, cut out from a plastic lemonade bottle. It worked for me, and apparently a lot of motocross folk use the trick too. If the seals are damaged, then obviously, it won’t work.

 

Nothing to lose and may save you a lot of time and money. 

[Griff 1,556]

12 hours ago, RC166 said:

It’s worth having a go a cleaning any muck out around the seals without taking any thing apart. Have an internet search on front fork DIY oil seal cleaning tool or similar. I followed instructions and made one, cut out from a plastic lemonade bottle. It worked for me, and apparently a lot of motocross folk use the trick too. If the seals are damaged, then obviously, it won’t work.

 

Nothing to lose and may save you a lot of time and money. 

 

Yes I agree with this suggestion. I used some photographic material cut from an old X-ray of one of my legs. That put a stop to the issue. However as MatBin also suggests, a bike left lying up for long periods can leak. Not just from drying seals but also from deformation of the seal from being parked up in the same position too long. I have heard of new bkes on shop floors leaking for the same reason without ever being used. 

[rjp996 1,091]

I've changed my seals a few times now - its not a complex job at all, just a few 'tricks' to make your life easy. If you have a garage its a 3hr job prob start to finish not going very fast and having a couple of tea breaks.

Get a low profile hex socket rail from machine mart makes the job to undo the top clamp 'clamp' hex nuts.

loosen the top of the legs before loosing the bottom clamp.

Take the front wheel off and crack the hex bolt that holds the internal piston in place (you need a long hex socket for this)

I bought a cheap 'laser' seal driver, and use the old seal on top of the old one when putting he new seal in place.

When re filling the forks i use 7.5wt oil and use a plastic tube and a syringe to suck out the oil to the right level.

 

With the manual its a simple step my set task (just crack the top and bottom fixings before taking it out of the clamp is my tip)

 

 

[Noel Hynes 28]

Hi everyone- thanks for your comments and advice. One fork has lost a lot of oil- so my gut feeling is to just get the two done- I have ordered the parts from Wemoto.

 

Will keep you posted. I am very surprised still with the leaks- I bought it last August and did a couple of runs- it was laid up in the garage over the winter and was not used until the Covid restrictions were eased up... The pleasures of motorcycling.

 

Noel.

[neojynx 722]

20 hours ago, rjp996 said:

I've changed my seals a few times now - its not a complex job at all, just a few 'tricks' to make your life easy. If you have a garage its a 3hr job prob start to finish not going very fast and having a couple of tea breaks.

Get a low profile hex socket rail from machine mart makes the job to undo the top clamp 'clamp' hex nuts.

loosen the top of the legs before loosing the bottom clamp.

Take the front wheel off and crack the hex bolt that holds the internal piston in place (you need a long hex socket for this)

I bought a cheap 'laser' seal driver, and use the old seal on top of the old one when putting he new seal in place.

When re filling the forks i use 7.5wt oil and use a plastic tube and a syringe to suck out the oil to the right level.

 

With the manual its a simple step my set task (just crack the top and bottom fixings before taking it out of the clamp is my tip)

 

 

As above. It is very straightforward if you take your time.  Only difference for me was that I used a piece of plastic piping as my seal driver which worked just fine and is far cheaper than buying one.

[Can do biker 32]

I had to replace mine after 15K and now one of them is leaking again (7K later).  It has been off the road since March though, so maybe the lack of use has exaggerated the problem?  I haven't had much success with the plastic cleaning trick, will try again, but sadly i think a new seal is needed again.

 

I replaced them myself which was easy enough as folk above have said.  Personally I would leave the one that isn't leaking well alone as it is easy to damage the seal on fitting if you aren't careful.

Edited August 11, 2020 by Can do biker

[outrunner 4,457]

A bit of cling film wrapped over the top of the fork stanchion will protect the seal from damage.

 

Andy.

 

 

 

[Noel Hynes 28]

Hi everyone. Just thought I would give you a wee update on the fork seals.

 

After consideration I contacted a mobile bike mechanic and on Friday last week he came and fitted two new seals. Interesting he did say when he took them apart- someone had been in at them before. We noticed a couple of pits on the  both forks and also a little metal spike which may have damaged the seal on one. Both were leaking so got both done.

 

We had a chat about this happening on a bike which even although is 5 years old has only done just over 3000 miles- he did say he has seen this before irrespective of the mileage etc and not just on the NC etc. One thing he did advise was to purchase gaiters to cover all or part of the fork as this can give protection from stone chips/damage etc.

 

He did an excellent job and I felt better to get an expert doing it as the steering/suspension is too serious to mess up. He allowed me to watch him doing the work which was good and I picked up a few tips.

 

I do like the bike but as before very disappointing to have this problem on a relatively newish bike. I am sure the problem was there when I purchased the bike last year- but I only had a couple of runs before putting it away for the winter. I took it out for a run on Saturday afternoon and what  a difference and so far - NO LEAKS...

 

Fingers crossed.

 

Noel.

[ChrisCB 6,671]

Lack of use can cause these problems, my friends Ducati garage queen, about 2k a year, has to have the Öhlins forks serviced every new season.

[outrunner 4,457]

I would put it down to lack of use, my 2016 bike with 53000 on it has the original seals in the forks, also has the original Nissin rear pads as well.

 

Andy.

[trisaki 2,029]

If not using the bike  its worth  pumping the forks up and down say once a month 

[electric_monk 270]

On 8/24/2020 at 16:05, Chris750 said:

Lack of use can cause these problems, my friends Ducati garage queen, about 2k a year, has to have the Öhlins forks serviced every new season.

 

Don't understand this.......

[Slowboy 20,425]

On 25/08/2020 at 15:53, trisaki said:

If not using the bike  its worth  pumping the forks up and down say once a month 

I spray a bit of Mr Sheen (other silicon polishes are available) round the seals before pumping them up and down prior to a layup of more than a week or so. Like Andy said earlier, use is often the best type of maintenance 😁

[Noel Hynes 28]

Thanks Brian - great tip - I will give that a go. Thanks to everyone for feedback and comments- all very much appreciated. Noel.

[davebike 943]

Hi Poaching thread 

My 2018 NC75X dct  has the later forkes with the black plastic top "nuts"  8 sided and either 38 or 39mm   any idea other than Honda who dosea socket or worst case a spanner ??   I anm not having much luck sorcing one !  anyone know for sure if the earler nuts fit the later forks?  tube part nos are different !  I do not like plastic nuts !

 

[Screaming Skull 349]

Deltec Industries do a 38mm Octagon Impact socket, they can apparently make sockets to order

[skorpion 945]

On 9/5/2020 at 08:04, davebike said:

Hi Poaching thread 

My 2018 NC75X dct  has the later forkes with the black plastic top "nuts"  8 sided and either 38 or 39mm   any idea other than Honda who dosea socket or worst case a spanner ??   I anm not having much luck sorcing one !  anyone know for sure if the earler nuts fit the later forks?  tube part nos are different !  I do not like plastic nuts !

 

 

The fork caps are not plastic, you can undo with adjustable spanner.

I replaced mine with Chinese copy Honda 41mm alloy caps.

https://www.that auction site.co.uk/itm/41mm-Front-Fork-End-Cap-Screw-Bolt-Fits-Honda-CB400SF-VTEC-NC39-1999-2006-2007/143426413293?hash=item2164e162ed:g:g~8AAOSwFN9duJ3J

[DCTPaul 629]

as mentioned above...

try cleaning them first - camera film or thin feeler guage.

cling film over the stantion plus fork oil smear when pushing new seals down and fitting new seals in to fork bottoms

go OE seals... its such a faff job dont use cheap ones...

plastic tube cut and slit to act as a fork seal driver.

cling film or plastic bag over the nut / under the socket to protect finish