leaking forks

[rij1]

Both my forks are leaking fluid from the top of the dust shields and is getting on the motor with help from the wind. Also they have about 4-5 inchs of travel while rocking back and forth. What do I need to change? I have the air valve on mine with 20psi.

[TOOLS1]

Seals, and fluid.
TOOLS

[motogrady]

Tools is correct.

You might get away with taking the forks apart, and just cleaning everything
including the seals, but if you're that far, might as well put a new set of seals in
whilst you're  there.

[rij1]

Do I need any special tools for this job? Should I be good just changing my fork seals or change the fork piston ring as well?

I think while im doing it, It would be a good time to lower a couple inches.

[tcazes]

you will need to use pvc to make a tool to slide the seals in or just get the tool for it.

[rij1]

How do I know what size seal I need?
Vintage vintagecb750 for my year 81-82 has 27 x 50 x 11 and partzilla for my year 81-82 has 37 X 50 X 11 and 2 part #'s

http://www.vintagecb750.com/products/3/suspension/52/fork-tubes-fork-seals

http://www.partzilla.com/parts/search/Honda/Motorcycle/1982/CB750F+A/FRONT+FORK+81-82/parts.html#uloc10

[shinyribs]

motogrady wrote

Tools is correct.

You might get away with taking the forks apart, and just cleaning everything
including the seals, but if you're that far, might as well put a new set of seals in
whilst you're  there.

Quted for posterity. How many times do you hear a WV boy say ''whilst''?

[shinyribs]

rij1 wrote

How do I know what size seal I need?
Vintage vintagecb750 for my year 81-82 has 27 x 50 x 11 and partzilla for my year 81-82 has 37 X 50 X 11 and 2 part #'s

http://www.vintagecb750.com/products/3/suspension/52/fork-tubes-fork-seals

http://www.partzilla.com/parts/search/Honda/Motorcycle/1982/CB750F+A/FRONT+FORK+81-82/parts.html#uloc10

If that one seal is truly a 27mm I.D. there's no way it fits your bike.

27x50x11 = 27mm i.d.   50mm o.d.  11mm tall.

[rij1]

You are right, I didn't think about that. 27mm is a bit over 1" and 37 is a bit under 1 1/2".
I'm guessing vintagecb750 mis printed their part dimensions.

[rij1]

Where should I order from?
Should I order the piston ring also or any other parts in the fork assembly?

[TOOLS1]

Did I say you needed a piston ring?
TOOLS

[motogrady]

It can be a tricky job guy.

some guys leave the forks on the bike, take the top caps off (the things with the air valves),
pull the springs out, drain the fork oil (small screw on the bottom of the sliding part of the fork),
remove the front wheel (you need to block or strap upt the front end, the bike is front heavy),
pry the dust boots up and off, and remove the big circlips that hold the seals in. at the very bottom
of the forks, under them at the end, is a I think 7mm allen screw.  Take that out.  If it seems to turn
and spin with nothing happening, take a broomhandle and insert it in the fork from the top,
pushing down as you turn the allen screw.  This keeps the nut inside from turning also.
When that screw is out, the lower leg should slide right off.  Then remove the seal.
I usually just get a big flat head screwdriver and gently pry it out, working side to side.
Repeat with the 2nd fork.

On that seal, if you look closely, will the the size of it in mm.
Order that, or just take it to a Honda dealer and lay it on the counter to match up with what they have.
Get all the gunk out of the lower slider, if you look in there with a flashlight, you'll see a bunch of sludge in the bottom. Install the new seals, I set them with a big socket and hammer, but anything that's
a bit smaller in diameter will drive them in place, even plastic pvc.

Put everything back as it came off.  I dab a bit of silicone or permatex on the 7mm screw
to help with sealing, but if the washer down there looks good just go with it.
Make sure those 7mm screws are tight.

I use 20 w oil, some guys use ATF, either is good.

First time, it will take you a day, easy.  
After that, 2, 3 hrs and yer riding......................

[rij1]

No piston ring,

Thanks for the info motogrady, But i'm going to have to take care of something else that came up first. I'm going to post a new thread regarding it..

[tcazes]

also check the manual but 20psi seems high. that may have blown them. maybe back off the pressure and it will stop leaking. i use 15wt fork oil with no air and its plenty stiff. also i think its easier with them off the bike but it is equally just as quick to leave them on the bike since it is less to disassemble. good luck and take plenty pictures.

[TOOLS1]

The DOHC forks have bushings, and because of this the seals must slip on over the tubes after they are inserted into the sliders. This means the forks need to be removed from the bike to install new seals.
TOOLS