Fork Oil Seal Leak

[darrsi]

Personally, i'd keep the good seal, and replace the whole bike around it.........  :lol

[unfazed]

One question. Is it actuallt leaking or just residue from oil from the fitting of the seal? Lift the dust seal and wipe it clean inside and over the top of the seal, re fit the dust seal and take it for a spin and check it again.
You should always replace the oil in both fork legs not necessarily the fork seals and fork dust seals. Replace it with 10w oil and ensure you have an air gap of 121mm (4.75inches) or 132mm (5.2 inches) in the models with fork adjusters, that air gap is more important than many think. The air gap is checked after filling the fork leg with oil and before replacing the springs and spacers with the fork leg fully compressed standing upright. The distance the oil is from the top of the fork leg should be 121mm.  More than 121mm will make the forks feel softer and less than121mm will make them feel harder. I usually fill the fork a bit more than is needed and then using a syringe with a tube at the end cut to the length I require and resting it on the top of the fork leg suck out the excess oil. Repeat the process for the second leg. Then replace the springs spacers and fork cap.
A word of advice loosen the top clamp bolt before loosening the fork cap and tighten the fork cap before tightening the top clamp bolt.
In answer to His dudeness, I do not think it is a very good comparsion you can still ride and stop with a leaking fork seal. Why would yamaha supply seals indivudally if you had to replace the set. You do not have to replace all the brake seals but when overhauling the brakes you are stripping out all the pistons and seals and it is advisable to replace them all for safety. Yet Yamaha suppy single  brake seal and brake dust seal in kit form not the whole set for the caliper.
Nice one Darrsi never thought of that  :rollin

[His Dudeness]

One question. Is it actuallt leaking or just residue from oil from the fitting of the seal? Lift the dust seal and wipe it clean inside and over the top of the seal, re fit the dust seal and take it for a spin and check it again.
You should always replace the oil in both fork legs not necessarily the fork seals and fork dust seals. Replace it with 10w oil and ensure you have an air gap of 121mm (4.75inches) or 132mm (5.2 inches) in the models with fork adjusters, that air gap is more important than many think. The air gap is checked after filling the fork leg with oil and before replacing the springs and spacers with the fork leg fully compressed standing upright. The distance the oil is from the top of the fork leg should be 121mm.  More than 121mm will make the forks feel softer and less than121mm will make them feel harder. I usually fill the fork a bit more than is needed and then using a syringe with a tube at the end cut to the length I require and resting it on the top of the fork leg suck out the excess oil. Repeat the process for the second leg. Then replace the springs spacers and fork cap.
A word of advice loosen the top clamp bolt before loosening the fork cap and tighten the fork cap before tightening the top clamp bolt.
In answer to His dudeness, I do not think it is a very good comparsion you can still ride and stop with a leaking fork seal. Why would yamaha supply seals indivudally if you had to replace the set. You do not have to replace all the brake seals but when overhauling the brakes you are stripping out all the pistons and seals and it is advisable to replace them all for safety. Yet Yamaha suppy single  brake seal and brake dust seal in kit form not the whole set for the caliper.
Nice one Darrsi never thought of that  :rollin

they also supply single clutch plates, springs etc etc don't think that indicates anything other than it's all about the dolla baby! you could buy one spark plug if you want. doesn't mean its right. i'd replace the two seals you'd do one. thats ok. you have to embrace difference thats what make the world go round  :lol

[DryRob]

DryRob okay cheers I will message him and see what he says but I don't want to rush into anything and have to spend loads and loads, for the moment its quite a small leak and the next MOT is due next June. What you say about the bushes is interesting considering the mechanic did say the bushes are worn. Also interesting, how come it wouldn't be advised to mix tubes and lowers as I don't really have a lot of experience with forks? Would it be because of different rates of wear? Thanks again for the tips everyone

To be honest I was just guessing that a damaged bush could be allowing the inner to wobble and compromise the seal, I'm not a mechanic and probably wouldn't have suggested the bush if you'd not mentioned it and gone with a pitted/damaged inner. The only reason I said to not mix uppers/lowers is I think I read it in pointer to null's guide not to mix components between forks, maybe that's overcautious but as a fork comes as a set each part will bed into the other differently depending on the fork.

I'd like to know for future reference if I'm talking shit though.

[unfazed]

DryRob, Certainly a possibility but that kind of wear at 21K would only be the result of an impact. If there was wear you would see score marks on the bush or the slider or both. You are correct in not mixing parts , it is as much common sense as being over cautious as no two parts wear the same.
His dudeness :way to philosophical for me 

[darrsi]

"....the bike is in brilliant condition except for a fairly large crack and hole in the front fairing on the left side above the leaky fork...."




Coincidence ??  :rolleyes

[Yamazer-92]

Hi Unfazed yeah it is definitely leaking, I have wiped under the dust seal before but I tried it again yesterday and just riding 12 miles today to college and back was enough to leave quite a big line of oil, doesn't help that the roads directly around my house are really bumpy. Yeah darrsi that's why I mentioned the damage could well be something to do with it, I will take a photo at some point but been busy lately and want a pic in the daylight really, will probably take one tomorrow. Hmmm not good I dont know how I didn't spot it on the test ride (I was actually pillion for the ride and my dad took me out as I was still on 33bhp restriction at the time  :rolleyes ) or how the dealer didn't spot it during the MOT and small service they did  :\ .... I asked Markbubble but he has sold the forks already unfortunately. I guess I have 2 options then; replace the seals again with genuine Yamaha ones and dust seals too which will be £40 for both and cross my fingers or sell a kidney and get some replacement forks. Where would be good to try and get 2nd hand decent condition ones at a similar age for my bike do you reckon? Thanks again for all the help!

[unfazed]

Go the cheapest option first.
Replace the seal and dust cap with a genuine yamaha one. When you strip the fork leg check the bush and the inside of the slider for were marks. When you put the seal on from the top make sure the fork leg is as clean and smooth as possible and the leg and seal are well oiled especially the seal tips. Make sure the top of the fork leg is clear of any metal bits from the aluminium fork cap which can lodge there after removing the fork cap.