Topic: Fork Seal leak

[GroovieGhoulie]

I made my long drive home today and it was awesome.  Except for a sore butt after a few hours, I feel great.  It was a great ride, even if the 400 isn't too fond of highways.

Anyway, the only problem that developed was the left fork started leaking.  The rubber "dustcover" over the lower fork had fluid seeping from the top, (quite a bit) where the fork slides in and out of, and there was dirty oil on the fork across the length of its "travel".

The right one is fine, however, since I'm going to be here for 10 days, I figure I have time to service the forks.  I suspect the seal let go in the left fork and plan to replace both seals and oil in both forks.

Where to go to get new seals?  Honda dealer?  I can't wait on an online order, so I'll buy it OTC.  Also, how hard is it to replace the fork seals?

[n9viw]

If you want OTC, then the $tealership is probably your only hope. Replacing is not hard at all:
* Put bike on center stand
* Elevate front of bike (or put weight on rear seat to elevate front)
* Remove front wheel
* Remove brake caliper and fender
* Remove fork leg
* Drain fork oil from drain screw (leave top cap ON for now)
* Turn fork over, remove allen bolt in fork leg
* NOW remove top cap CAREFULLY (spring pressure behind it)
* Remove spring
* Remove dust cap
* Remove c-clip above fork seal
* Carefully clamp lower fork leg in vise (I wrapped mine in an old welding glove)
* Depress fork slider all the way
* Quickly pull slider all the way to its top limit

This is pretty much what I've done on all my CB forks. Once the slider is out, I use a seal puller to get the fork seal out. I also pull the damper out once the slider is out, wipe it down and make sure all the little holes are clear. Reassemble in reverse, and you're all set. I usually assemble the fork first, then put the new seal over the slider with a liberal coating of grease. I use a PVC tube over the slider like a slide hammer to tap the seal into place, and the slider helps keep the seal straight as it goes in. If you're rich, you can get and use one of those seal setting tools, but I've gotten by fine without one thus far.

[xcbxer]

Make sure inner tube is mirror smooth, and not pitted or corroded or it will just leak again.

Fill up with recommended exact volume of recommended oil or ATF.

[Surly]

If you get the seal out intact you can take it to a bearing supply place and they should be able to measure the seal and sell you two new ones. If your handy with measuring insruments measure the fork tube outside dia. and the inside dia. of the seal fit and take those numbers with you. Or just take the parts (clean of course) in and they can find a replacement seal for you. They should be very inexpensive this way too. Although sometimes non-motorcycle places get scared when they see bike parts. 

[scott_cb650]

I had to order seals from a dealer on ebay just because the local dealers didn't have any and I gave 1 dealer 6 weeks for my order to come in and it was always on back order.

Got 'em from ebay in less than a week.

The hardest part for me was getting the old seals out.  Had to do some serious prying with a strong/thick screwdriver to get them out.

Over all though, it's a simple process.

Also: An impact wrench helps in getting the bolt out of the bottom of the fork.

[GroovieGhoulie]

OK, I'm looking at the microfiche drawing of the fork and I'm wondering, should I replace other items at the same time, such as the dust cover or other seals?

The seal is part #16, but I'm wondering if I should also replace 6 and 7.

http://www.psndealer.com/fiche/images/Honda/1976/Motorcycles/1936_FRONT%20SHOCK%20ABSORBER.gif

[bistromath]

Those seals can be ordered from JC Whitney or any number of the other online motorcycle suppliers.

If you want to save yourself endless frustration, drive the forks to a garage and get a guy to remove the bolts from the bottoms with an air wrench, as suggested above. They will turn freely without breaking free of the fork tube if you can't provide the impact torque.

[supersport_CB400F]

Those bolts can be bugger to get out (tip...free them before you remove the plug bolts at the top of the tube)  and they're attached to the part 7, it’s not part of the seal stuff but if its worn replace it, but from experience they are usually fine, it actually sits at the end of the damper rod as indicated in the drawing

[GroovieGhoulie]

I've got an impact wrench, so I should be good.

Gonna try and order the parts "overnight" tonight and hopefully get them Monday or Tuesday.

I called six local places and no one had the seals.

[GroovieGhoulie]

Does anyone know of places that ship overnight?  I've tried JC Whitney, Service Honda and Crotchrocket.com and no one lets you specify your shipping preference.

[BobbyR]

If your find the bolt at the bottom just spins and does not back out. Take a broom handle and tap the rounded end into the internal tube lightly. This is a old time trick that really works.

[Jonesy]

One trick I saw for removing the old seal was to use a curved motorcycle tire iron (or tire spoon to some people). This works well since you can get a good grip on the underside of the seal while using the upper rim of the lower fork as a fulcrum.

Does anyone know of places that ship overnight? I've tried JC Whitney, Service Honda and Crotchrocket.com and no one lets you specify your shipping preference.

JC Whitney lets you pick your shipping options and they use FedEx for expedited shipments. I just ordered from them yesterday and that's what they offered...

[Paul]

Just another quick tip.
Before you remove the forks, loosen the top Filler / Spring retainer bolt whilst the clamps are still holding the sleeve tight.
rather than putting them into a vice

And another one, As you open the lower fork drain bolt, and stratagically place a dish under the fork leg, Watch as the oil shoots across the room horizontally before it eventually settles to a drip into the dish

[turtle]

My mechanic told me to give them a good clean once they are disassembled. I sprayed them with degreaser and rinsed with the hose, making sure they were properly dry before refilling.