Fork seal change?

Craig321 · 22 Aug 2015 at 18:44

I had my Hornet out today and the left hand fork has a leak. Couldn't fix it despite cleaning with sealmate (which has worked in the past).

I have the Abba front stand, so no problems there.

Do I need any special tools to do the job? How difficult is it to do? How do I know how much fork oil to put in - the amount of oil depends on your weight/style for older forks, doesn't it?

Also, will a kit like this do? http://www.ebay.co.uk/itm/Fork-Susp...ornet-98-13-/390952044692?hash=item5b068ec894. Is that the price I should be looking to pay?

Thanks.

wazza300 · 22 Aug 2015 at 18:51

I doubt youll need the shims/bushes

just the seal,ive never doen one in a modern bike though ive just took it to a shop to do

the manual should tell you how much oil per fork leg,stand the fork upside down overnight in a container to let it fully drain out

I doubt it would cost much if you can take the loose fork to a shop

Craig321 · 22 Aug 2015 at 19:37

Yeah I suppose I could take the loose fork + seal kit and ask them to do it. If it's going to save me a lot of pain, then I'd rather spend an hour on labour or whatever I guess.

But what is it that makes it worth taking in?

As I'm taking the forks off anyway, is it not worth doing the bushes anyway?

wazza300 · 22 Aug 2015 at 19:39

you can if you want to,idk how youd tell if they are worn or not,maybe slight play in the fork

theres a circlip that holds the seal in and the stanchion to the lower leg,take that out and then pull on the stanchion till it seperates,last one I done on a 100cc bike was a right pain to seperate

Scythe · 22 Aug 2015 at 20:08

Take it to a decent suspension place and they're rebuild and adjust it all to your weight and riding style, it's supposed to make a world of difference. It probably wouldn't cost much more to do too if you're supplying loose forks.

Craig321 · 22 Aug 2015 at 22:21

Hmmm yeah might do, although I'm not that bothered about a setup on this bike, as long as it's stock then it'll be fine. I just want to mess about with my Hornet really, a bit of a project bike where it doesn't matter if I don't finish a job over the weekend as it isn't my main bike anymore.

I just want to get it roadworth again really. Brakes were almost siezed today after it only sitting, covered for the last 5 months or so. That's probably down to the left caliper that's really messed up though. Not having much luck with one on eBay

. Plus I want to stick the SP Engineering Moto GP stubby on, looks & sounds ridiculous

wazza300 · 22 Aug 2015 at 22:23

Yh they will,pays to pump them now and again

Split the caliper and rebuild it?

Craig321 · 22 Aug 2015 at 23:03

wazza300 said:
Yh they will,pays to pump them now and again

Split the caliper and rebuild it?

I messed up the bit where the slider pin went in trying to get it out (pin is stuck). Didn't realise the metal was so soft, so ended up denting a bit, so no chance getting that out now

Dogbreath · 23 Aug 2015 at 14:35

Craig321 said:
Do I need any special tools to do the job? How difficult is it to do? How do I know how much fork oil to put in - the amount of oil depends on your weight/style for older forks, doesn't it?

You should stick to the amount of oil, or preferably the air space recommended by the manufacturer. There is little to be gained by changing this other than very harsh suspension and popped oil seals if you overfill the forks. The workshop manual (or Haynes if available) will cover the oil volumes/air gap required and will show you how to dismantle the forks.

You can change the oil viscosity to adjust the damping, but using higher viscosity oil on the Hornet to improve low speed compression and rebound damping will give too much high speed damping, causing the forks to become harsh on rough ground. This is a compromise that all old fashioned damper rod forks suffer from.

The spring is the part that you might want to change according to your weight. If you go to a heavier spring, then consider going up a grade on the oil.

It's unlikely you'll need to replace the bushes unless your forks are noticeably sloppy (push/pull bike with brakes on and check for sideways movement between the fork tube and stanchion). I would recommend that you pay for genuine Honda forks seals, many of the aftermarket seals are visibly inferior with less sealing lips etc.

The only really tricky bit with damper rod forks is the bolt in the lower end of the fork that retains the damper rod itself. These can be tricky to undo, since there is nothing stopping the damper rod rotating inside the fork, and these bolts are sometimes loctited. You can make a special tool consisting of a sharpened broom handle to force in the end of the damper rod (after removing the top cap and spring etc.) to hold it still if this is a problem. Using an air impact wrench (or a decent electric one) increases the chance of removing the bolt with no problems.

Craig321 · 23 Aug 2015 at 18:00

Cheers

I watched a pretty good video last night and it all looks pretty simple if you take your time. The only thing I'm not sure about is the seal tool, to drive them back into the fork. The guy in the video made a home made one with some pipe and clamps but it looks more of a faff than it's worth.

I guess I could always take it to the shop just to drive the seals in.

.one. · 23 Aug 2015 at 18:22

Craig321 said:
Cheers

I watched a pretty good video last night and it all looks pretty simple if you take your time. The only thing I'm not sure about is the seal tool, to drive them back into the fork. The guy in the video made a home made one with some pipe and clamps but it looks more of a faff than it's worth.

I guess I could always take it to the shop just to drive the seals in.

Not sure on your fork specs but I use a socket same size and the old seal to drive the new one in, main thing is evenly all around when driving home.

Craig321 · 23 Aug 2015 at 18:40

Hmm good idea! I suppose I could always take it all apart and give it a go as there's no rush. If something goes wrong or I can't do something I can take it in.

Dogbreath · 23 Aug 2015 at 19:50

.one. said:
Not sure on your fork specs but I use a socket same size and the old seal to drive the new one in, main thing is evenly all around when driving home.

You can't use a socket to drive in fork seals since the fork tube has to be in position when the seal is fitted.

A length of PVC tube of appropriate diameter works well (e.g. waste water pipe from B&Q etc.) , but I've also used a narrow drift with no problems before, you just work your way around the seal being careful not to damage the outer sealing lip. A piece of small diameter wooden dowel would probably work fine for this.

~Dockie · 24 Aug 2015 at 02:09

my biggest advice is don't buy cheap seals.
took me about 3 hours to do both forks. originally put cheap seals in which popped within a week, had to do the whole thing again! I never bothered changing the bushes or dust seals, so that kit seems a bit much imo.

http://www.ebay.co.uk/itm/Castrol-F...-x-500ml-1L-/281572562817?hash=item418f085781

http://www.ebay.co.uk/itm/Genuine-H...00-NC30-NTV-/170847910754?hash=item27c7543b62

i used some plumbers pvc pipe to knock the new seals in. Not sure how much oil you need off the top of my head and i dont have my haynes manual to hand but i'd imagine 1L would be more than enough to do both fork legs.

.one. · 24 Aug 2015 at 03:14

Dogbreath said:
You can't use a socket to drive in fork seals since the fork tube has to be in position when the seal is fitted.

Like I said in my post not sure what forks he has but you can on gs1000s gs550s most older 80s bikes you can use my poor mans method with out any problems if care is taken.

Dogbreath · 24 Aug 2015 at 07:23

.one. said:
Like I said in my post not sure what forks he has but you can on gs1000s gs550s most older 80s bikes you can use my poor mans method with out any problems if care is taken.

No you can't, it's physically impossible. You might be thinking of fitting oil seals to the wheel hubs or engine cases which is easy to do with a suitable socket, but you absolutely can not use a socket to fit seals to forks.

Since you can't pass a fork tube through the middle of a socket, the fork tube would have to be removed first. In order to remove the fork tube, the upper fork bush also has to be removed. You could then fit the seal with a socket, but there is no possible way you could fit the fork tubes back into the lowers, neither the lower or upper bushes would be able to get past the seal.

If you could fit seals in this way, there would be no need for the special split seal drivers which are sold for the job. The "poor mans" method of fitting fork seals involves a length of PVC pipe, not a socket.

.one. · 24 Aug 2015 at 12:03

Dogbreath said:
No you can't, it's physically impossible. You might be thinking of fitting oil seals to the wheel hubs or engine cases which is easy to do with a suitable socket, but you absolutely can not use a socket to fit seals to forks.

Since you can't pass a fork tube through the middle of a socket, the fork tube would have to be removed first. In order to remove the fork tube, the upper fork bush also has to be removed. You could then fit the seal with a socket, but there is no possible way you could fit the fork tubes back into the lowers, neither the lower or upper bushes would be able to get past the seal.

If you could fit seals in this way, there would be no need for the special split seal drivers which are sold for the job. The "poor mans" method of fitting fork seals involves a length of PVC pipe, not a socket.

Of course you need to remove the fork tube to do my method lol I always clean and inspect each leg full strip down while I replace a seal.

gs1000 gs550 sr250 xs400 z650 z1000 rs250 the list goes on all can be done this way.

Done a gs550 2 months ago this way have done for the past 30 years on older bikes.

Here is some dude doing a xs400 socket and old seal would do the same http://www.fmbikes.com/2012/02/fork-seal-job-for-the-xs400-reassembly/

Sandycheeks · 25 Aug 2015 at 08:06

I have used a paint roller sleeve to knock seals in place, just make sure it's clean.
Any bit of pipe that fits over the fork is ok as long as it's not sharp and preferably plastic so it wont scratch your fork.
Like has been said - the bottom bolt can be a pain, apart from that they're easy really, just take pics along the way then you can reference back when re-building them.
I usually clean the inside of the fork with white spirit then a quick spray of carb cleaner.

Dogbreath · 25 Aug 2015 at 10:36

.one. said:
Of course you need to remove the fork tube to do my method lol I always clean and inspect each leg full strip down while I replace a seal.

gs1000 gs550 sr250 xs400 z650 z1000 rs250 the list goes on all can be done this way.

Done a gs550 2 months ago this way have done for the past 30 years on older bikes.

Here is some dude doing a xs400 socket and old seal would do the same http://www.fmbikes.com/2012/02/fork-seal-job-for-the-xs400-reassembly/

Look at the following pic of the Hornet forks, note part number 8 (the lower bush). The bush is larger than the diameter of the fork tube, explain how you could fit this through the fork seal (without ruining it)?

CB600F Front Fork

.one. · 25 Aug 2015 at 16:06

Dogbreath said:
Look at the following pic of the Hornet forks, note part number 8 (the lower bush). The bush is larger than the diameter of the fork tube, explain how you could fit this through the fork seal (without ruining it)?

CB600F Front Fork

LOL Why not try reading my other posts at the start I said not sure of his fork setup and replied with many 80s bikes can be done my way, which you quoted implying they could not.

Please do not feel the need to reply thanks.