Is there a quick and dirty way to do fork seals without a press?

Hi All,

I have a leaking fork seal on my '80 CB750K and the manual shows
the procedure for replacing it - but it requires use of a press plus a
"spring installation tool" to put the fork back together. I assume the
spring is strong enough that trying to manhandle it together would be
impossible. I don't have a press as large as what would be needed.
Is there a way to reassemble the fork without using a press or is
this a job that you can't do without using one?

Ted

 

Wrong on both counts. Does google work for you? The simple pragmatic
answers are right here in this NG, they've been posted over and over.

 

Here are some sites that I found useful when I rebuilt my forks:

http://www.motorcycle.com/mo/mcnuts/forkseal.html
http://www.motorcyclecruiser.com/tech/replace_fork_seals/
http://www.nobugs.org/bike/forkseal.html

-Scott

 

These are worthless. They are basically online versions of a procedure
out of a Haynes or Clymer manual, generic one-size-fits-all ones. It's
not that the overall procedure is bad, it's that none of the details
specific
to my fork is included. Keep in mind I'm working on a 26 year old bike,
not a 5 or 10 year old bike like what was used for these articles.

This one is good, but it's not the same bike model. The water trick is
a great idea. Note particularly the sentence:

"...Usually, people recommend putting the lower leg into a vice and pulling
hard on the fork tube. This didn't work for me. Now that I've seen the
disassembled fork, I don't see how this could possibly work on a CB500 fork.
The two bushings just get wedged together...."

In other words, according to the author of the 3rd article, the procedure
listed in the first 2 articles wouldn't have worked.

If your going to deviate from the FSM, and I have plenty of times in the
past on a number of vehicles, the details of how you go about doing that
are very important, that is usually where generic how-to articles fall down,
and it's why I never work on a vehicle anymore without a FSM.

Thank you though for the links, the water idea was worth wading through
them.

Ted

 

If you don't believe the factory manual lists a press as a requirement I
will post a
scan of the relevant page. That count I'm definitely right on. Sheesh!

I wasn't looking for a step by step guide, I already have that. Frankly
the DOHC CB750s were kind of a little slice in between the SOHC 750's
and the later Nighthawks and such. It doesen't appear they were that
popular,
most motorcycle histories seem to ignore them, and cross references
are surprisingly wrong about them - for example if I see yet another
manufacturers cross reference that claims the same air filter fits in the
1978 and
prior CB750's as what fits in the 1979 and later CB750's I'm going to
scream.
Honda did carry some parts from the SOHC bikes forward, but I have
run into plenty besides the engine that is different, and I'm not going to
assume that Honda didn't screw with the forks also.

Ted

 

Read your own subject line. You started this silly thread, Ted.

So? You were raised by your sisters and there wasn't much male
influence in your formative years? Does that explain all this hysteria
you're posting?

 

Oh, you are SO superior, Ted!

But *why* are you jerking our chains with question about " a quick and
dirty way to do
fork seals without a press?"

Any pragmatic home mechanic knows how to build a simple tool to do that
simple job.

 

Well, fair enough, but a quick read suggests that that's pretty much the
procedure I've used on '81, '83 and '86 Hondas with no problems. I
suppose the '80 CB750 might be radically different, but it seems unlikely.

(Except I wouldn't call it "pulling" the stanchion, more hammering it
outwards, if you see what I mean. Impact needed to drive the top
bushing and fork seal out.)

-----sharks

 

You're fucking welcome.

My CB900F is 24 years old. Do you think I was able to find any procedures
online that were specific to my bike? No. Boo-hoo. And yet some of the
information I found online was still useful. I rebuilt my own forks, using
ad hoc procedures and improvised tools, with excellent results.

So you have the factory manual, and you already know the generic techniques.
Exactly what are you asking for right now?

I wouldn't put water in my forks.

-Scott

 

No such problem seems to exist.

According to www.partsfish.com, the 1979 CB750L, and 1979 and 1980
CB750K use the same fork. There is NO bushing, just a dust cover, a
retaining ring and an oil seal.

The fork slider tubes seem to be expected to handle the sliding loads
that you'd expect an upper bushing to control. They don't even have
Suzuki's trick teflon coated
shims.

All Ted needs is a large socket to remove the fork caps, an Allen
wrench of the correct size and maybe an air impact wrench to loosen the
lower bolt, a small screwdriver to pop the retainer out, a larger
screwdriver to pop the old oil seal out and a piece of PVC tubing that
he can use to drive the new seal into the slider with whatever is
handy.

Ted doesn't need a fork spring compressor, all he has to do is stand
above the top of the fork cap and push it down with enough force to
compress the spring with his own weight.

I accomplish this feat by standing on a plastic milk crate, if I
haven't actually remove the fork leg. If I've done that, I can find a
way to secure the fork tube vertically so I can fill it to the correct
level and reinstall the fork spring by standing above the fork cap.

 

I've done this successfully many times. It sometimes helps if there's a
second person handy to twiddle the nut the first few threads while you
push it down.

 

Jim says:
I hold the cap down with one hand (supporting most of my 205 lbs with
that hand) and turn the fork tube with the other hand to thread the
cap on. This is easier for me than having to readjust my grip on the
cap as it screws into the tube.

The only thing that I have ever used the press for in rebuilding
forks is (if I only want to replace the seals and change the oil) to
push out the seals.
To do this, I:
a. remove the circlip which retains the seal.
b.remove the cap and fill the fork (extended) with cheap oil.
c.compress the fork with the press (with the bottom of the fork
sitting on a block of wood in a wash tub and a rag wrapped around the
fork at the seal area), which causes the oil to push the seals out of
the fork legs.

..

 

I either do that or else stick a socket and sliding T-bar on the fork
top, a wad of rag on top of the T-bar, push down on the wad with
one hand (and most of my weight) and turn the T-bar handle with the
other. You only need a half a turn to pick up enough of a thread
if you're lucky.

To drive in the seals, either use a bit of PVC pipe as someone
mentioned, or for tricky, deep-seated seals like on the XLV you
can use a PVC pipe adaptor of the right OD and with the ID bored
(or filed, at a pinch) to just a smidge bigger than the stanchion,
drop that over the stanchion and drive it in using a bit of steel
pipe as a hammer (end-on, over the fork leg, hell, I need a photo
don't I ...). The adaptor keeps the seal nice and square, and the
pipe hammer means you hit the adaptor evenly on all sides.

------sharks

 

I want to make sure there are no gotchas on this one, basically. That is, I
don't
want to get halfway through the job and end up with the forks in a cardboard
box going to a shop because some critical little piece that requires the
right
tool, not a makeshift one.

I've done plenty of makeshift tools before, all I wanted to know is if
someone
out there has actually done a makeshift job on these specific year and model
forks, that's all. Your and anyone else are welcome to review the parts
explosions
all you want and sit around and armchair guess as to whether they are
similar enough
to forks you have worked on and done makeshift jobs on, but your not going
to
be sitting on the garage floor at 11 pm cursing because now you have to
drive the
van the next day instead of riding.

Ted

 

IMO, you have been given adequate information to do the job. I've rebuilt
forks with less information (and probably less experience) than you have,
including forks that "required" a press and other special tools. I'm not
going to review your parts diagram for you -- I did that for my bikes, you
can do that for yours.

But let's examine your options.

#1, tackle the job and successfully rebuild your forks. Problem solved.

#2, tackle the job and fail, then have a shop clean up your mess. You get
to drive your van for a few days, then you can ride again.

#3, take the forks in and have a shop rebuild them. You get to drive your
van for a few days, then you can ride again.

#4, keep second-guessing your ability to complete the repair. Your forks
will eventually run out of oil and/or ruin your brakes. Now you get to
drive your van indefinitely, and you still have busted forks.

Your call.

-Scott

 

Hi Tom,
So you have also used a broom handle to hold a back-up to take the
allen bolt out of the bottom of an old set of forks. All right! Oil
field engineering rules!

Jim

 

I thought everyone knew that dodge....

 

Oh, and Ted forgot to tell you his Honda's paint code, and the engine
and chassis serial numbers! Only collectors with the same color Honda
and a *lower* serial number should offer information about "quick and
dirty" repairs.

Ted must maintain the quality of "quick and dirty" repairs to the
highest standards of hysteria. "Quick and dirty" repairs must only be
performed with approved and certified home brewed tools.

Yes, Ted is *so-o-o* right. If you have never done a 100 point
restoration on a 1980
CB-750K, any information you have to offer about "a quick and dirty"
method of fork repair is worthless!

You are not in the position of being blacklisted by Sotheby's auction
house, you know. Ted has his position and credibility in the Classic
Universal Japanese Motorcycle Cadre" to uphold, and he will not bear
the scorn of the esteemed membership, should one of his "quick and
dirty" repairs be detected by one of the
collectors of Fine Olde Junque.

 

No, it's not worthless. It's not what I needed or asked for, that's all.
You
assume way too much than what's good for your health.

Booger, please go out on a ride and get your blood pressure down
before you pop a vein, I'd surely miss your future ranting here if
you were to keel over.

Ted

 

Yup, more than adequate, and I appreciate it, whatever people may think.

You forgot #5:

#5 Don't bother asking questions or thinking about it, just dive in and do
it,
and if you stumble into something you haven't taken the time to think about
in advance and have to take the works to the shop, then come here and
post about it so everyone can have a good laugh.

I think some of the posters are disappointed that I didn't do #5. ;-)

Ted