Fork seal dilemma..

Vindaloobeast

Registered
Im picking up my 2007 Busa from a UK dealer on Saturday but I went in to have a look at the bike last weekend for a final checkover and found the left fork seal was leaking quite badly for a 7,500 mile bike.

I had emailed the shop with no reply but rang them today and they told me the bike was in the workshop and they had just finished replacing the faulty seal.......one side.

Hmm. I had asked them to do both as a precaution as I didnt want to leave one fork full of old oil and the other with new oil plus no-one knew the status of the 'good' side.....for all I know it could be empty..!!! Even so Im a bit fussy about things being done right and I wanted to ensure the forks were balanced properly.

Should I be worried...? Cos I aint happy.

Beast.
 
Both should be done at the same time with the same oil, and same ml of oil..
I would not settle for less... At 130+ miles and hour just in the 1/4 mile everything needs to be done right.

1ibandit
 
There is big myth / misconception out there the subject of the forks being different causing problems with tire wear etc. It is just not true. Once bolted together they are one unit and work together despite any differences. Some bikes will have rebound valves on one side only and compression on one or both sides. I’ve seen one that only had a spring on one side.
Think about it… that axle does not flex. If it did the lateral pressures would cause all sorts of issues.

On the other hand whatever caused the one seal to start weeping could have lessened the life on the other side. You might work out a deal with them to service the other side at a reduced cost to prevent it later. I ran one for some time that was weeping on one side and the other never started. There were pretty well abused with wheelies at the drag strip.
 
Professor:

I am not by any means an expert on this, but I worked in a bike shop for 3 years ( for Free ) just so I could learn how to do my own bike work. Each time Dave ( owner ) showed me how to do the seals he told me of how you must get them as close as you can to each other. At the time we would test each spring, messure out the oil and get everything as close as we could. He never told me you can do only one side and not the other, but he never did just one side.

He passed away a short time ago so I can't ask him. If this was a bike I was going to get. I would ask for the money off they charge to do the one seal, and then I would do both myself. We have a great guide in the DIY. If Vindaloobeast can't do it himself he will have to deside how to move on... I for one would not do just one seal...

Best of luck Vindaloobeast..
1ibandit
 
Ive got seals done twice, both places said we just do both. Didnt really ask why, just said "Okay"
 
@Professor: Not sure who your post was aimed at, the original poster, those who said "do both sides", or the shop. Nevertheless, yes to an extent you are correct. The forks are a unit once assembled. Where that generalization breaks down is that the two fork legs are independent of each other. That is, the only link they share is through the front axle. They don't share fluid or any other linkage. If the oil in one side is changed, and the other side is not, the two will have different actions. The older oil will be (probably) more viscous (and dirtier), and therefore the parts inside will wear differently. Yes, some bikes have split the actions of the forks, so one side handles compression, the other side rebound, and yes, some have even had a spring on only one side. However, most performance bikes, the Hayabusa included, have forks where both sides handle all duties. Thus, if one side is cleaned and refilled with oil, and the other has not, the suspension will not function properly.

Further, as pointed out elsewhere, before that one seal was replaced, both seals were (presumably) the same age. Just because one has failed and the other has not, doesn't mean the "good" one isn't days away from going out too. Just as you don't reuse gaskets on the engine, you shouldn't be "reusing" other worn parts either.
 
@Professor: Not sure who your post was aimed at, the original poster, those who said "do both sides", or the shop. Nevertheless, yes to an extent you are correct. The forks are a unit once assembled. Where that generalization breaks down is that the two fork legs are independent of each other. That is, the only link they share is through the front axle. They don't share fluid or any other linkage. If the oil in one side is changed, and the other side is not, the two will have different actions. The older oil will be (probably) more viscous (and dirtier), and therefore the parts inside will wear differently. Yes, some bikes have split the actions of the forks, so one side handles compression, the other side rebound, and yes, some have even had a spring on only one side. However, most performance bikes, the Hayabusa included, have forks where both sides handle all duties. Thus, if one side is cleaned and refilled with oil, and the other has not, the suspension will not function properly.

Further, as pointed out elsewhere, before that one seal was replaced, both seals were (presumably) the same age. Just because one has failed and the other has not, doesn't mean the "good" one isn't days away from going out too. Just as you don't reuse gaskets on the engine, you shouldn't be "reusing" other worn parts either.

Professor is absolutely correct.

Not saying it would not be a good idea to replace the seal in the opposing fork while you are in there but not necessary. I think the shop/dealer where he purchased the bike did exactly what was required, found a leaky seal on a presold bike and made the necessary repairs! Thumbs up to the dealer!

If the purchaser wants both forks serviced then he should pay for the second fork. Simple solution.

A fork is a mechanical device and anything mechanical can fail. Doesn't mean the other fork is about to fail as well.
 
@Professor: Not sure who your post was aimed at, the original poster, those who said "do both sides", or the shop. Nevertheless, yes to an extent you are correct. The forks are a unit once assembled. Where that generalization breaks down is that the two fork legs are independent of each other. That is, the only link they share is through the front axle. They don't share fluid or any other linkage. If the oil in one side is changed, and the other side is not, the two will have different actions. The older oil will be (probably) more viscous (and dirtier), and therefore the parts inside will wear differently. Yes, some bikes have split the actions of the forks, so one side handles compression, the other side rebound, and yes, some have even had a spring on only one side. However, most performance bikes, the Hayabusa included, have forks where both sides handle all duties. Thus, if one side is cleaned and refilled with oil, and the other has not, the suspension will not function properly.

Further, as pointed out elsewhere, before that one seal was replaced, both seals were (presumably) the same age. Just because one has failed and the other has not, doesn't mean the "good" one isn't days away from going out too. Just as you don't reuse gaskets on the engine, you shouldn't be "reusing" other worn parts either.

My post was direct to the OP because of the "balance" concerns. I've seen incorrect posts on this board before. Like stating the rebound and compression adjustments needed checked that they are the same because of uneven tire wear.

As a background I've owned a very small shop many years ago that I ran part time in outside my primary job. I've done suspension service on a Showa, KYB, and Ohlin components, front and rear. However the majority of it was motocross bikes. So I see both sides of it. If it was my bike I would service both sides. However I would not expect the shop to foot the bill for the other side. If it was my shop, I'd offer up to service the other side for a reduced fee to attempt to maintain a higher level of customer satisfaction. I would disassemble, inspect, reassemble with a new seal and wiper. If I saw damage while I had it apart, I'd even pick up the entire bill. However I can see why the shop would not be willing to do both and foot the bill for the entire project.
At 7500 miles it is still fresh. Ironically it is at the "factory service" mileage point where they are to be inspected." Inspect for oil leakage, scoring, scratches on tubes. Replace any defective parts." The service manual does not say " if parts defective parts are found on one side replace both" There are plenty of Busas that have gone 50K miles plus without touching the forks. So I wouldn't expect the other side to fail if there is no evidence of oil seepage currently. Depending on the shop I think he has as much a chance of them servicing the good side improperly as seeing it fail if left alone.
I disagree with this statement However, most performance bikes, the Hayabusa included, have forks where both sides handle all duties. Thus, if one side is cleaned and refilled with oil, and the other has not, the suspension will not function properly. The remaining side is still functioning correctly. @ 7500 miles the fluid is still fine. The only thing that might be slightly suspect is the seal. There is a chance the other side failed to abuse. An abrupt set-down from an excessive wheelie could have damaged it but to a lesser degree. Small chance if it is not leaking now. In a dirt bike world, they usually get packed with mud between the wiper and seal. You just don't see that with street bikes.
With your argument, why wouldn't you be campaigning to service the rear shock as well? It has the same 7500 mile inspection period, on the same bike, subject to the same conditions.

If I have a tire fail on one corner of my car, I only expect the dealer to replace the defect tire under the warrantee. Not all 4.

Yes I would service both.
No I would not expect or demand the shop to foot the bill for the good side.
Most of the time I replace front and rear tires at the same time when the front is still good for 2-3000 more miles.

I'd better get of here. I actually have a new set of forks sitting on the bench I need to go install on my bike! :)
 
Some good debate here. The grey area for me is that I dont know the state of the 'good' side..for all I know it might be empty of fluid but unlikely or may have been serviced previously with a different grade of oil or level. Im dreadfully fussy with my bikes and like everything to be right and would have been happy if the other leg had fresh fluid..the old seal could have stayed. Im bothered.

The shop has been ok thus far. I discounted them £200 from the asking price and they replaced the stator cover with a genuine part (£56) as the previous owner had let it go down in a fall off the stand. They have done the weepy seal too so I dont want to push my luck. Bike is under warranty for 3 months so when I pick it up I will check all the settings and return the suspension to factory and then if anything goes wrong I can go back to them.

I dont have the tools to tackle the forks on my own..last time I tried on my GSXR1100 I pitted the leg accidentally and have to have them reconditioned.

I'll post some pics when she arrives.

Beast.
 
Its fairly rare to have fork seals fail that early on a street bike unless its been wheelied or it had the freak bug/road tar etc get stuck to the fork leg, which damaged the seal. I've replaced one bad seal on several bikes and never had the other one ever leak. I personally wouldn't worry about it.
 
Professor, I'll defer to your shop experience on the forks, and I can kind of see your point on the quality of the oil in the remaining leg. My own experience has been that if one side has gone, both sides should be looked at, specifically because in most cases whatever affected one leg probably affected both legs (hard landing from a wheelie, big pothole, etc). Unless the one side failed because of some foreign material that got onto the fork leg, or a seal had a defect, any wear is going to be visible on both sides. I would think that the unaffected side should be opened up at least to check the oil level so the repaired side can be filled to the same level.

Regarding the shop checking it, I would think it would be more cost-effective for them in the long run to do both sides since they've got the bike apart anyway, as having the customer come back a couple of weeks later with the other side gone isn't going to make said customer very happy. Plus, while it's a little more work now, it's one less time up the lift and pulling all the parts off vs having the customer come back.

As for looking at the rear shock, I probably would anyway, but then I'm the kind of guy who would want at least two tires on my car replaced if one failed, to keep wear more even. Car shocks are generally replaced every 30,000 to 50,000 miles, but they are far less critical than the suspension on motorcycles. I seem to recall reading an article in Motorcyclist some years ago where they did a fork rebuild on a bike, and discovered that the oil was totally degraded with only 15,000 commuter miles on the bike. They recommended replacing the oil fairly regularly, as it does degrade due to heat, wear of the fork internals, and age.
 
I picked the bike up today and I have to say its quite amazing. Im still getting used to it as the ride is quite firm although it appears to be on standard settings.

There is still a ring around the leg which I will keep an eye on..it doesnt appear to be leaking any fluid visibly now so thats good.

I have posted another thread about a small issue with a mark on the rev counter so if you could all have a peep I would be greatful.

In the meantime Im going to get used to the bike and give it the beans....the motor is stonking compared to my old R1 and is soooooooooooooooo easy to ride in traffic.

I did question the shop when I picked it up about the dirty oil in the other leg but they said it will be fine and thats the way it will stay..!!!

Beast.
 
Great congrats .
Nothing like piece of mind and if it bothers you take it somewhere else and have other fork done .
 
Its fairly rare to have fork seals fail that early on a street bike unless its been wheelied or it had the freak bug/road tar etc get stuck to the fork leg, which damaged the seal. I've replaced one bad seal on several bikes and never had the other one ever leak. I personally wouldn't worry about it.

Just read this again. Where I and the former keeper live the city is plagued with potholes but also a ridiculous amount of speed humps...and I mean ridiculous.

I wont be pulling wheelies.............:whistle:

Beast.
 
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