Fork removal advice for my ZXR750J...

[Revtek]

Hey all.

I need some advice on removing the forks from my ZXR750J '91.
I'm having the seals replaced and a general service done on them by a mechanic but it'll save me a fair bit of cash (that I don't have) if I just take him the forks.
My problems are that I don't have a manual, I don't have the right stands and i've never done it before.
So if anyone can offer some advice (especially ideas on how to suspend the bike once the forks are out) i'd really appreciate it.

Cheers.

[FrogZ]

As everyone else is out riding...
Two schools of thought, suspend from ceiling (not many, lots of chance of damage) and on trolley jack. Now dont forget you have to get it high enough to get the forks out of the bottom triple too .
If you go the trolly jack go to the effort to make yourself a nice wooden cradle as you will use it a bit.
I have gone both and there is a risk it will all end on the deck either way just be careful and dont let the kids near it or it WILL go over.
Visually inspect before undoing it, if you are unsure you will remember were cables go etc. draw pics. Pull off your fairings, tank (dont want to scratch it), mudguard, undo front wheel, have to drop calipers off.
I have tried dropping the steering head off hoping to save height but it is about the same i reckon
Easier to just undo bolts and drop out of triples.
Dropping the front wheel out, rather than as a set of forks wheel etc. save height too (it was a prob when I have done it, higher you go more unstable).
All over the place but hope you get the drift.
Make sure to stand back a lot and survey current progress with a beer in hand as this is when you note you havent udone cables and stuff I forgot to mention... on purpose of course... cant let you in on too many secrets or it wont fall over

[Revtek]

Thanks for the advice and the quick reply mate.

Fortunately the weather has been crap this weekend so it hasnt bothered me, but ill be dark if I miss much good weather ahead.

The cradle that you reccommend, does it go directly under the pipe?
There doesnt seem to be anywhere else to put it but i'm a bit weary of the pipe supporting the weight of the bike. Will this be a problem?

[WRT_GPX]

what are your fork seals like, infact this is probably a good time for somone to explain how you can tell when your fork seals should be replaced.

eg. people keep telling me that i should just go if its leaking oil... which mine arent but the top of the fork is all swollen and a bit crusty (whats this... the dust seal?)

[mike-s]

the black bit around the different diameter in the forks is the outer dust seal, the oil seal is buried deep within underneath a spring circlip to keep it in place.

basically if you see "streaks" of an oily substance on the forks extending down to a ring of the "oil" roughly where maximum fork compression happens, then the seals are shot. If they are USD forks, if you get oil pooling at the bottom of the forks/on the ground its another sign they are shot.

[mike-s]

shows fork seals taht are a bit shot
this shows a how to on replacing fork seals on a USD fork bike.
this shows replacing the fork seals on a normal non USD fork bike.

[FrogZ]

The cradle idea is to make up your own "wooden box" to sit the motor on and keep it level and stable. Some need it some dont, depends if you can find a flat surface under the motor. Also strong, you dont want to go punching the jack through the sump.

Usually the pipes run up one side or either side of the sump. Just make a cradle that supports accross the lot i.e. lifts on pipes BUT also on the sump. Dont go too big it is awkward, dont go to small it is unstable. Only limited by your imagination and woodworking skills.

I just jacked mine up on the sump but there was enough room and I still put a block in there to spread the load. That is, I didnt use a cradle for the 12 but I did on my 7 because of the awkward shapes under the motor.

Did that make more sense ??

With fork seals you prob will still need to take them to the dealer to get him to rattle them apart to replace the seals and then rattle them back together for you.

[WRT_GPX]

Oh, so if my outer dust seals are a bit crusty but theres no oil present at all and no streaking they should be right for a bit longer *well not too long to prevent crap getting in and scoring the forks*


i may get them done soon though with heavier oil cause im either bottoming out sometimes or its the fairing but something clicks when i hard front brake.

[Revtek]

Ill give the cradle a go, though my woodworking skills arent the best

Im getting a mechanic to do the forks as ive been told you need a special tool to remove the seals?

Theyre leaking pretty bad so I definitely need them done. They only started leaking since the bikes been off the road for the winter.

Ill let you know how it goes.

Cheers for your help.

[FrogZ]

WRT, oil viscosity acts on the damping or slowing action of the fork.
The spring decides how soft or hard, msot 250's are soft for some reason.
Clicks are more liable to be steering head bearings, maybe sticky pads/slave cylinders.

[Daisy]

The forks on mine click too. Just as you start to put weight on them. I know its the forks because the old ones that are sitting on the bench do it too.

[Revtek]

Well I finally got the forks out so I thought id post what I did to support the bike.

I tried the woodwork idea to create a template but as I said, my woodworking skills aint the best, so that failed pretty quickly.

What worked was to have 2 car jacks under the bike, one under the sump and one under the engine on the other side of the pipe to counter the weight. I raised them both bit by bit until the weight was fully supported and the bike was sitting straight.

Worked a treat.

[photomike666]

I used to pile bricks under the footpeg hangers in an attempt to copy a centre stand, then use a car jack to raise sump.

I also find it useful to loosen tight bolts (such as front wheel axle) before jacking the bike up, just to prevent accidents.