Right Shock slow leak - Does this affect the front braking

All, my XJ 750 has a leaky right shock, does this affect the brake fluid level? My front brakes do not really give you a good feeling when you are using them, you have to squeeze them pretty hard to brake. I noticed some hoses from the caliper go to the shock and I think it has something to do with pumping fluid into the shock on a hard front brake. Therefore if this is true does this mean all my brake fluid is going into the shock then leaking out?

How much of a pain am I looking at to fix the leaky shock? Should I just try and pick up some used shocks?

Any help is appreciated!

 

Is this bike a Seca?

 

I'm unclear as to how the anti-dive system on the 750 Seca works. However, one thing I *am* clear on is that brake fluid is certainly not pumped into the same reservoir in the fork as the damping oil. Mixing the two would NOT give good results.

According to the Haynes manual, working on the forks (the shocks are in the back, by the way) on any 750 is not a fun job. It *can* be done, but if this is your first time breaking open a set of forks, it's probably best not to do it on an XJ 750.

EDIT: By the way, a set of used forks is going to be more expensive than buying a set of dust seals and oil seals and having your local bike shop do the work for you. Forks tend to be a couple hundred bucks EACH... unless they're old, leaky forks, which you can get cheaper, but that's not much help, is it?

 

I will add that the leaky front fork seal will affect braking if the oil gets on the rotor!!!! get that fixed soon. If you do not want to do all of the work yourself then take the forks off and hand them to the bike mechanic. Lots cheaper this way. If you are friends with the mechanic see if you can look over his shoulder to see what he is doing. Fork seals go out all the time and it would be great to learn how its done and what tools to use.

Sean

 

The front forks on the 750 Seca have an "anti-dive" system built into them. Under hard braking, the brake fluid pressure (those are the brake lines "going into" the fork) closes off passages in the forks to stiffen compression damping and resist "dive."

How well the system works is a matter that is still under debate. Some folks swear by it, others have blocked off the anti-dive and claim they notice no difference.

The one thing the anti-dive system DID do was to make the front forks a lot more complex. Fork seals themselves aren't a difficult repair; getting the anti-dive braking system properly bled after reassembly is a hassle.

 

Yes it is a SECA.....

Thanks a million for this info. The leak is not that bad so I might just try and ride it some this summer....what damage could I really do??

I am very mechanically inclined however I have never torn into a pair of motorcycle shocks! I might save that headache for someone else.

 

You could crash. That's been known to cause significant damage to motorcycles and riders.

 

LOL....

OK you do have a point. The leak is not that bad yet....

 

I would suggest the "stitch in time saves nine" approach. Get to it sooner than later.
Post your general location and help might be near at hand to assist!

 

I am in West Virginia. Anyone around that area willing to tackle the seal replacement for a fee?

 

I have done mine before, 82 750 seca, and its not a fun task.
The suspension suffers, as will brake dive, and state inspection wont pass.
The bushing placment was the real trouble for me, but the bolt at the bottom can be difficult as well.
Patience and correct tools and small hands will make a world of diffrence.

 

Wow, that sounds pretty hard core. I might see if I cannot find one on ebay.

 

The down side to eBay is that a fork assembly is pretty expensive, and you might not get anything that's better than what you have now.

The up side to eBay is that even if you end up with ANOTHER set of forks that need work, you can send THOSE to the shop (or learn to do it yourself) with the spare set without tearing your otherwise working bike apart.

Fork oil leaks can get dangerous, though. I wouldn't take the bike on the highway until you get it fixed, and be cautious even at lower speeds (extra stopping distance, go slower than usual, etc.).

Good luck!

 

I had this same issue recently with my 900 forks. I took the fork off 3 times before I finally gave up and replaced my fork lowers with later model ones.

It will be fork oil that you're leaking and this will have an impact on the handling (especially if it runs out). The forks hold 286ml or 9.67 US OZ of oil so it wouldn't take that long for the fork to empty out.

Be better to bite the bullet and get it fixed.

There are 3 rubber o-rings in the anti dive, these are the most likely cause of the leak.

Here's what they look like on the inside:












These have not been completely stripped down. This is what you remove from the top only.

 

Beautiful Illustration of the Anti-Dive on the Seca-900

Note how the Unit is comprised of very few parts.
Note in the last photograph ... The Actuating Rod with the NYLON Bushing.

The Rod needs its full travel within that Nylon Bushing.
"Crud" can form causing the Rod to Stick or be seized.

Remove the Nylon Bush
Clean it with Dish soap and a Toothbrush
Twist a tightly rolled-up section of 1200 or 1500 Finishing Paper and remove any scratch or blem on inside diameter of the Nylon Bushing.

Lube the Rod and Bush with clean fork oil and see how well it moves.

 

What if I told you guys that mine is leaking at the top where the 2 tubes come together. Is that still the same as the illustration you are showing?

The top fork is just slightly wet and I usually just wipe it off when I get back from a ride.

I have no leaks down low in the anti-dive system.

Does this make the repair any easier?

Sorry to sound dumb but I have never really done much with bikes.

Thanks

 

Either the air JOINT o-rings are bad, or it is leaking out of the top CAP BOLT (another o-ring/gasket in there).........

 

Re: Right Shock slow leak - Does this affect the front braki

I belive when he says, "mine is leaking at the top where the 2 tubes come together", he is indicating a fork seal has gone bad.
If you have a manual and the new parts on hand, I'd say Go At It!!
Prep yourself prior to and expect the task to take some time, as patience is the key.
Make sure to snap photos, or sketch the parts as they come out.
There are a couple pieces you would not want to mix up at the bottom of the assymbaly.

 

Yes, Ass.Fault you are correct. I have looked but could not find any fork seal replacement guides on this site...

Does one exist? Anyone care to at least get me started on that?

Should I get the fork seals from ebay or go to yamaha for that?

Thanks a million!!! This site is full of info!

 

Fork seals are about $30 from chacal. That's cheap enough that I wouldn't bother with eBay.

Disassembling the forks is necessary to replace the seals. Fork disassembly is described in both the factory manual and the Haynes manual. Those you *should* get from eBay, since they're more like $60 each. Used copies on eBay are much less.

Anyway, from what I can tell, aside from getting the forks apart properly, the big deal about replacing forks seals is these four things:

1) DON'T scratch up the inside of the stanchion as you dig out the old seal.

2) DON'T bother installing new seals if the fork tubes have burrs or marks, or if the forks are bent. Bent tubes must be replaced or you'll just ruin another set of seals. Burrs and scratches can be sanded off, if they aren't too bad, but again, they'll just tear up your new seals, so do that first.

3) DO use a large socket and a rubber mallet to pound in the seals. The socket ensures that you're pushing all around the new seal evenly. You DON'T want to push on one side, then the other side, etc. Drive it straight in.

4) DO lube up the inside of the stanchion and the seals with a little fork oil or 10W40 to make it easier to install them. If you try to shove them in dry, you'll tear them up.

The manuals kind of assume you know all that already, so they don't tell you.

Anything else I've forgotten?

 

Re: Right Shock slow leak - Does this affect the front braki

if the fork oil runs down to your brake pads, and or rotors you could find yourself in trouble. look in the FAQ there is a great step by step.

 

Good fork seal install guide here (for 650's, but the BASIC concepts are the same for all models):

http://www.xjbikes.com/Forums/viewtopic/t=8355.html

 

I started to tear into mine tonight to take it off of the bike.

How do I get the shock off of the tree? I have the anti-dive with the air nozzle and cannot figure out how to remove the shock from the entire tree.

Any help?

 

Re: Right Shock slow leak - Does this affect the front braki

Don't do this without the manual. The manual will walk you through the steps, including how to remove the forks from the tree.

Even more important, the manual will have the torque specs so you can be sure it stays together on the road.

 

Ok, I will try and pick me up a manual on ebay. I was just attempting to take the fork off so that I could take it to the shop to have the new seals put in it.