Fork Oil Seal Leak

[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