Topic: fork locked up

[jonda500]

  I just purchased these "fork Honda CB 500 Four" off ebay. If I can fix them I believe they will be the correct forks for my 550F and the 500 forks currently in my 550F will be used in my bitsa 500/550 project.
  The listing did mention "a fork is locked". They failed to mention that the seal area on both forks is heavily damaged. I have disassembled both to get a feel for how they work and why one is seized. One of the axle caps is not a honda one  .
  The seller said the seals and clips were missing but didn't mention that the rebound spring was missing in the locked one. With the top cap off, spring out and the 6mm allen bolt removed from the bottom the dampening pipe/piston falls out the top when inverted but unlike the left one has no rebound spring. The 'oil lock piece' seems to be loose in the case but the chrome slider and the alloy case are seized together in the full out position. I can think of ways to hydraulically press the slider into the case - but that may just make things worse!! How can I apply a pull apart force to it? Sorry bout the long read, thanks for your interest, John 

[Rookster]

Clamp the fork tube in a vice and try to tap the fork leg off it.  The aluminum is quite soft so go easy.  A block of wood between the hammer and the lip of the fork leg should help cushion it.

Scott

[jonda500]

I have already tried hitting the top with a heavy chunk of hardwood as hard as I dared but it didn't budge at all. When I spray penetrating oil in the seal cavity it quickly drains past the seizure and drips out the bottom...
John

[jonda500]

I thought of filling it to the top with oil, replacing the cap bolt and fitting a grease nipple to the drain hole so as to be able to pump it out with a grease gun but with no dampening pipe/piston in there, there's nothing for the bottom allen bolt to screw into and there's no way to block the hole as I can't get to the inside of the hole...
John

[scottly]

What does the damage in the seal area look like? Did it come from bent fork tubes?

[jonda500]

The chrome tubes are in great condition so I assume they are replacement tubes. The left fork slider does get a little stuck if I push it all the way in with the spring removed - very possible the originals were bent . I think very likely actually!
I have a set of 750 forks that I hopefully can install these chrome sliders into?
John

[scottly]

Try rolling the tubes on a flat surface and look for wobble.

[jonda500]

Damn! The stuck tube is bent - did I buy a pair of boat anchors?
John 

[bryanj]

Once only in all the shop years i had a bent alloy slider after an accident so could be that, those are 550 forks as calliper fittings on both

[jonda500]

   So not only is the chrome tube slightly bent, the alloy bottom part must have also been tweaked... and I feel like somewhere in it's past someone probably knew this and was careful not to mention it. Oh well, I do pay too much for my lessons sometimes... But why is the left one not damaged at all?
   Well, I will now be able to see if it's possible to turn my 750 forks into 550 forks by just swapping the chrome tubes (one of them), if it fits I might be able to just try and get one more 550 chrome tube.
   The part numbers are different for the damper tube but in the pictures they look identical - I will report back with results and pictures when I do this. Now where did I put those 750 forks again???
John 

[bryanj]

500/550 & 750 tubes lengths are different

[jonda500]

to clarify, what I mean is I will try to make one 550 fork using the bottom of one of the 750 forks and the tube from the left (not bent) 550 fork. and if successful then look for another straight 550 tube to make the second one from the other 750 fork's bottom. (Obviously I will have to use the springs from the 550 forks as they will also be shorter I presume.)
John

[Mark1976]

   So not only is the chrome tube slightly bent, the alloy bottom part must have also been tweaked... and I feel like somewhere in it's past someone probably knew this and was careful not to mention it. Oh well, I do pay too much for my lessons sometimes... But why is the left one not damaged at all?
   Well, I will now be able to see if it's possible to turn my 750 forks into 550 forks by just swapping the chrome tubes (one of them), if it fits I might be able to just try and get one more 550 chrome tube.
   The part numbers are different for the damper tube but in the pictures they look identical - I will report back with results and pictures when I do this. Now where did I put those 750 forks again???
John

   Do as you please but if it were me, I'd contact the worthless POS that sold them to you on ebay and get some clarification about the condition of the forks as you received them.  Get a refund, your throwing good time and money after a two pieces of junk. This is what ebay has been reduced to, selling junk for a quick buck.

[Don R]

 Agreed, I'd file a claim. It sucks someone would pass off junk as good usable parts.
 
  I've mixed and matched 550 and 750 fork parts, a set of 550 forks had "341" stamped into the lower same as a set of 750 forks I had. I also bought a set of 550 chrome tubes to make a set of short 750 forks for a drag bike I am assembling.

[Tracksnblades1]

Agreed, I'd file a claim. It sucks someone would pass off junk as good usable parts.
 
  I've mixed and matched 550 and 750 fork parts, a set of 550 forks had "341" stamped into the lower same as a set of 750 forks I had. I also bought a set of 550 chrome tubes to make a set of short 750 forks for a drag bike I am assembling.

   So not only is the chrome tube slightly bent, the alloy bottom part must have also been tweaked... and I feel like somewhere in it's past someone probably knew this and was careful not to mention it. Oh well, I do pay too much for my lessons sometimes... But why is the left one not damaged at all?
   Well, I will now be able to see if it's possible to turn my 750 forks into 550 forks by just swapping the chrome tubes (one of them), if it fits I might be able to just try and get one more 550 chrome tube.
   The part numbers are different for the damper tube but in the pictures they look identical - I will report back with results and pictures when I do this. Now where did I put those 750 forks again???
John

   Do as you please but if it were me, I'd contact the worthless POS that sold them to you on ebay and get some clarification about the condition of the forks as you received them.  Get a refund, your throwing good time and money after a two pieces of junk. This is what ebay has been reduced to, selling junk for a quick buck.

+3…. And leave a discription with negative review….
I’d rather admit I got scammed instead of allowing to go on…
But Mark Twain made his point about trying to convince someone….

[jonda500]

I certainly will be contacting the seller - lets see if they care about their ebay rating at all!
I don't mind admitting I got screwed - but it is also my lack of foresight for buying something that they never did claim was good to go...
I guess when you pay a lot to be scammed you learn the lesson better though. I will try and get the item cost back!
John

[scottly]

Aren't the K3-K6 750 lowers the same as the 550 lowers? Do you have a good set of 750 forks? IIRC, the 550 tubes are 1" shorter than the 750 tubes, but one could slide the tubes up 1" above the top triple to get the same ride height.

[jonda500]

Aren't the K3-K6 750 lowers the same as the 550 lowers? Do you have a good set of 750 forks? IIRC, the 550 tubes are 1" shorter than the 750 tubes, but one could slide the tubes up 1" above the top triple to get the same ride height.

I do have a set of 750 forks (and no 750 bike)- and yes, that was my original plan. I even have a set of clip-on's that would neatly fit on the 1" that pokes out the top, but, I have had a change of heart about the direction I want to head in when I get to my Bitsa project. I am currently thinking that I would rather make (and ride) a fairly original looking bike than a cafe racer or chopper style bike.
John

[jonda500]

Well I got the right side one apart!
I laid the fork front side up along the horizontal brace of my steel work bench with a wood chock under each end and used a hydraulic bottle jack to push down on the middle of the fork tube.
I don't know which flexed more, the bench or the fork but after doing this the tube moved when I held the fork upside down and slammed the top into a piece of wood.
So then I removed the allen bolt from the bottom, took out the spring and refitted the chrome fork bolt in the top. After protecting the tube with a wad of rags either side, I clamped the top end in the vice horizontally and the bottom case came off after just one wack with the end of a 5 foot long piece of 4x6" hard wood.
The left side tube wont go in very far to the right side case so the case is definitely bent...
The right side tube is bent by about 2mm - maybe it could be straightened enough to work? Probably not!
I will use the left one to verify that my 750 forks (341's) can be converted into 550 forks and then order new chrome tubes - pics when I get to it!
John