Topic: Please confirm? likely fork seal damage(first cb so im learnin)

[[Blank]]

Hello all,

I replaced my front wheel today on a 1972 cb750. As soon as I removed the top bolt on the top tree to lower the fork tube so I could attach headlight brackets while I had the wheel off, the left bottom fork began to drip oil continously. I reattached wheel and one washer, one locking washer and the bottom end piece on either side of the forks, tightening with the final hex bolt of course. The left side still continous to drip at anywhere from 8 to 22 seconds. was there supposed to be a seal of sorts? Like o-ring or gasket etc? Picture included. That "racing strip" is oil leaking between the fork and bottom piece. I have let to bleed anything or change oil in tubes (if that is the correct terminology..) from the looks of it, both sides are evenly tightened and flush with the forks. No leak on right side.

[goldarrow]

There's an Allen head bolt on the bottom of the fork.  Oil may be leaking from there.  You will need to remove wheel and axle to see the bolt.

[BobbyR]

You will not get a fork seal leak in a fork not moving since there is no pressure. I doubt it would leak even if it were grossly overfilled without pressure. You most like suspects is the side drain bolt which does have a crush washer. Teflon tape one bolt at a time to see which is leaking.

[[Blank]]

Wow those are both really easy things I can try thanks!  If I toy with the Side drain bolt will it squirt fluid everywhere? Basically will I make a mess adjusting it?

[tfrasca]

Yes. If you remove that bolt on the side of the fork leg, oil will come out. If you just wipe it off, you should be able to tell if that's the source of your leak.

[BobbyR]

Wow those are both really easy things I can try thanks!  If I toy with the Side drain bolt will it squirt fluid everywhere? Basically will I make a mess adjusting it?

You tighten it not adjust it. I suggest you get a copper washer under that bolt. Do not over tighten or you may strip it. You are dealing with aluminum.

[[Blank]]

Ok. I'm find the part number and size and get that to me asap if it's the culprit. I'll "TIGHTEN" not adjust. Thanks for the clarity.

[[Blank]]

Yes. If you remove that bolt on the side of the fork leg, oil will come out. If you just wipe it off, you should be able to tell if that's the source of your leak.

Ok, it's definitely not this bolt. I went to attempt to tighten it and it's on there rock solid. In a healthy way, not a Stuck on there way. Looks like removing the wheel is the next move.

[jamesbekman]

Replace the copper washer.

Cheers,

James

[oldhatt45]

Blank,

Listen to calj737. 
Just a couple of other little details to add to calj737's information, if you don't know already.
The Allen Head bolt in the bottom of the fork can be a little difficult to remove.  You may need an impact driver to remove it.
When putting that bolt in, the torque spec is around 18 ft-lbs. 
Don't forget that Crush Washer!!!!!!  LOL
The axle clamp that comes off the 2 studs in the bottom of the fork leg is Directional!!!!
Make sure when you are putting it back on that the longer side of the clamp is toward the front.
When you put that clamp back on, you tighten the Front nut first, then the back nut. 

Charlie

[[Blank]]

To be clear, when you dropped the axle clamp (lower piece of fork leg that axle passes thru) and removed the wheel, the fork lower has 2 studs protruding. Lie down, and look up at the bottom of the fork leg, between the 2 studs. You should see a socket head screw (Allen type). That holds a rod inside the forks. It needs to be installed with a crush washer, copper or aluminum, doesn't matter. It sounds like your leak is coming from that screw.

If you remove it, fork oil is coming out, be prepared! secure the top of the fork tube in the triple tree. This will assist in preventing the rod attached to the screw internally from spinning with the screw. Make sure to use a correct metric sized Allen too. A second pair of hands might be needed to ballast the bike if the screw is securely torqued. If it's already loose, remove the screw completely and verify a crush washer. If you have a copper washer, clean it, and re-anneal it. Then re-use it. Replace screw.

Now, remove the drain bolt on the side of the leg (the one that's really tight) carefully with a hex wrench. Pump the forks to force old oil out, replace screw.

Go to the top, unscrew the top nut, be mindful it's under some compression still due to a spring. Fill tube with correct type and volume of oil (see manual) and replace top nut. Replace axle clamp on wheel, re-torque carefully, and enjoy.

Should take you about an hour to do a proper job if you have the oil and measures ready. And a catch pan for the old oil.

Wow, thank you SO much. This sounds exactly like what I may have triggered when I was messing around with the triple tree and all the rookie mistakes I made.

Is it true I can reanneal with a blowtorch? I don't even know what this entails. Although I have no gripes about getting a new washer. I'll definitely have my brother in law help me out on this. I don't have an impact driver. Will any one do? Nor a torque wrench, so the same-any one will so? I can pick them up if u can recocannd. Once again, big thanks. This puppy runs but I'm doing a large once over to get it back to somewhat of a baseline since there are random mods (wiring..Ugh). I'll look up the oil and amount and drain and refill as u advised. Sounds fun!  Once again, I sincerely appreciate the time u took to help me. I don't feel as sunken anymore haha.

[[Blank]]

Blank,

Listen to calj737. 
Just a couple of other little details to add to calj737's information, if you don't know already.
The Allen Head bolt in the bottom of the fork can be a little difficult to remove.  You may need an impact driver to remove it.
When putting that bolt in, the torque spec is around 18 ft-lbs. 
Don't forget that Crush Washer!!!!!!  LOL
The axle clamp that comes off the 2 studs in the bottom of the fork leg is Directional!!!!
Make sure when you are putting it back on that the longer side of the clamp is toward the front.
When you put that clamp back on, you tighten the Front nut first, then the back nut. 

Charlie

Oldhat, I was curious if they were directional! I bet I won't know if I still have a leak until I do everything and put new oil in. It has probably bled itself dry on the left side. But I will use your advise as well. For sure.

Silly question: is it "dangerous" to ride with only fork oil in one fork? In the circumstance I need to move the bike. Which is looking more likely daily.

[oldhatt45]

Blank,

As far as the Impact driver goes, if you are asking about a hand type, a member on this forum Ilbikes sells a GREAT Hand Tool type impact driver as well as JIS spec screwdrivers (which I would strongly recommend).  I would recommend you contact him about these.  If you want an electric Impact Tool, all I can tell you is that I have a Very Old Electric Craftsman Impact Tool that works for me.  (I needed to use the electric wrench to remove mine.)   If you are looking at an Air operated Impact tool, other members will have to chime in.

For Torque wrenches, there are many different types.  From the Old style with a bar and scale to the latest digital type.  I have a relatively old micrometer adjust type torque wrench (Craftsman), but again, it depends on your budget and how accurate you want to be as well as how much you'll be using the tool to justify the cost.

In answer to your question about riding with oil in only 1 fork leg goes.  If it were my bike I would not do it.  You don't say how far you have to move the bike, so that may play into the answer, but I'll leave the answer to those that know a lot more than me.

Also, a couple other things.  Take pictures of everything before you take it apart!!! As you take things apart, take pictures of each piece so you know what it looks like before and can compare to when you are replacing or putting things back together.  Make sure you read the shop manual(s) a couple of times before doing anything.  Would also suggest printing out a copy of the parts breakdown so you can tick off what you took apart and how it came apart.

Hope this helps,

Charlie

[[Blank]]

Oldhat, calj thanks for advice. My distance would be 9 miles but I'll shy away from that idea until I get some oil in. Thanks for the pointers on the impact driver and torque specs. Will def got down and if I can't do on my own I'll take the notes and pick them up on weekend.

[[Blank]]

To be clear, when you dropped the axle clamp (lower piece of fork leg that axle passes thru) and removed the wheel, the fork lower has 2 studs protruding. Lie down, and look up at the bottom of the fork leg, between the 2 studs. You should see a socket head screw (Allen type). That holds a rod inside the forks. It needs to be installed with a crush washer, copper or aluminum, doesn't matter. It sounds like your leak is coming from that screw.

If you remove it, fork oil is coming out, be prepared! secure the top of the fork tube in the triple tree. This will assist in preventing the rod attached to the screw internally from spinning with the screw. Make sure to use a correct metric sized Allen too. A second pair of hands might be needed to ballast the bike if the screw is securely torqued. If it's already loose, remove the screw completely and verify a crush washer. If you have a copper washer, clean it, and re-anneal it. Then re-use it. Replace screw.

Now, remove the drain bolt on the side of the leg (the one that's really tight) carefully with a hex wrench. Pump the forks to force old oil out, replace screw.

Go to the top, unscrew the top nut, be mindful it's under some compression still due to a spring. Fill tube with correct type and volume of oil (see manual) and replace top nut. Replace axle clamp on wheel, re-torque carefully, and enjoy.

Should take you about an hour to do a proper job if you have the oil and measures ready. And a catch pan for the old oil.

Just fyi. U were exactly right. It wasn't hard to turn fortunately, but it just kept spinning. I pressed the fork up and prevented it from spinning until the Allen head bolt caught onto its tread.

Good times 

[goldarrow]

You're welcome.  See ^ reply #2

[[Blank]]

You're welcome.  See ^ reply #2

Goldarrow, thanks buddy.  You started it all. I owe you a nice glass of water on me if we ever meet in a bar.

[goldarrow]

You're welcome.  See ^ reply #2

Goldarrow, thanks buddy.  You started it all. I owe you a nice glass of water on me if we ever meet in a bar.

Which bar you go? South Side Dive bar?

[[Blank]]

I'm in the San Francisco bay area. And..I don't really drink hahaha.

[Stev-o]

You're welcome.  See ^ reply #2

Goldarrow, thanks buddy.  You started it all. I owe you a nice glass of water on me if we ever meet in a bar.

Which bar you go? South Side Dive bar?

Doubt it, they won't serve water in the SSDB!

My father-in-law warned me about those bars in San Fran...

[goldarrow]

You're welcome.  See ^ reply #2

Goldarrow, thanks buddy.  You started it all. I owe you a nice glass of water on me if we ever meet in a bar.

Which bar you go? South Side Dive bar?

Doubt it, they won't serve water in the SSDB!

My father-in-law warned me about those bars in San Fran...

You sure? They gotta at least serve you tap water, bring your own cup?

[[Blank]]

Lol stev-o. Not that kind of bar!

Not that there's aaaaaaaanytheeeeeng wrong with that.