my left front fork seal is leaking how hard is it too change?

[midnight1980]

and what seal do i buy?

[midnight1980]

oh i forgot too say oil, is coming out of the top seal, so is it number # 18 oil seal in the first diagram?.

[Snow]

They aren't bad - just follow the instructions. I believe it's even possible to leave the upper forks mounted to the bike, removing the caps (be careful, projectiles will want to fly out when you take off the caps), hit the bottom retaining bolt with air impact (there are other methods listed in the forums if you don't have impact), drain and clean lower and uppers along with spring, remove retaining c-clip from top of lowers, use seal remover (or in my case, tire iron - but don't use anything sharp like a screwdriver), slap new seal in (I suggest OEM), replace c-clip, reattach lower (using retaining bolt and impact), reinsert freshly cleaned spring, pour in proper amount of new 10wt fork oil, *carefully* reattach fork caps (do not strip!), and add air if you have air forks and no progressive springs.

Once you do it a time or two it is really easy and quick - maybe an hour if you take your time and sip a beer?

Yes, it is #18 in the first diagram.

Tools needed:
6mm (might be 5mm, but I'm pretty sure it's 6mm) allen socket. If you have a special you will need a long allen socket (think at least 2-3 inchs - I got a 6 inch set off ebay).
Impact wrench/gun/air socket wrench OR wooden dowel describe else ware in the forums.
Seal puller or similar device (I use a tire iron).
C-clip pliers/tool.

Parts: 2 oil seals
fork oil
Can or two of brake parts cleaner

[Crazcnuk]

First thing is to make sure it really is leaking oil.

I replaced a few sets of fork seals, as they seemed to leak every spring. Finally, I realized because my bikes usually sit outside all winter, I was getting water between the dust cap and the seal.

First few rides the water was getting forced out, with all the dirt, oil, etc that had accumulated under the dust cap and looked like the seal(s) were leaking.

If I leave them alone, they usually stop weeping after a few rides.

If it is an actual leak, and it's small, you can try changing the fork oil with an oil with seal swell in it. Sometimes that works too.

[Erik the Red]

one thing to add

The retaining bolt (Allen bolt #23 in diagram) is screwed into the Oil lock piece (#16 in diagram) -I think. If you have the misfortune of having one where the PO decided to loctite it in, you could be in for some extra fun. Impact gun will typically get it.

BUT... Just in case the impact gun doesn't do the trick, and the wooden dowel doesn't either, then check out this Tech Tip: Fork tool

I couldn't find a bolt that long, so I ended up using a long threaded rod with 4 nuts (2 tightened against each other on each end).

[John]

Make sure you buy OEM Yamaha seals . I have tried quite a few aftermarket seals and they all sucked!