Topic: Pitted fork repair

[onepieceatatime]

I was on the DOHC forum, and found this post from user Tourmaster. I am sharing the post here with his permission.

Okay Gene, here goes ... our local bike shop repair guy (Hugh), who I have a lot of respect for, was very forthcoming concerning his "Pitted Fork" repair weapon of choice.  Hugh has in the past used the epoxy trick, but later found that the farm and heavy duty equipment guys were repairing their pitted hydraulic cylinders with something a little more robust ... and just as easy to apply. Since using this simple product(s) over the past several years, he has had no returns from his many customers. 

I took some, rather crappy, photos of this stuff at his shop this morning.  It's actually a solder/braze like product that is simply melted into the offending pit area.  Here's the photo of the container that holds several of the solder like wires.

Product Name: Cronabraze 92C  CW1020 Acid Core


And here's the solvent/flux he uses to first prepare the area.

Product Name:  Cronasolv Eagle F930


Hugh said that the supply company he gets this stuff from is Lawson Products ... here's the link:
http://www.lawsonproducts.com/website/main.nsf/html/Solutions_Welding?OpenDocument
NOTE: In the photo showing Hugh's example, he was actually able to get the wire in shorter lengths contained in a smaller tube, rather that a large roll as shown this this catalog shot.

Here's their catalog for the specific items including the solder/braze wire:
http://www.lawsonproducts.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=75428&catpath=All+Products%2F%2F%2F%2FUserSearch1%3DBRAZINGSOLDERING

And next the solvent/flux:
http://www.lawsonproducts.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=75507&catpath=All+Products%2F%2F%2F%2FUserSearch%3DWELDING+PRODUCTS%2F%2F%2F%2FFLUX%2CCHEMICALS%2CPOLYMERS

I actually had a chance to watch Hugh do the repairs to my GS1100 fork tube, which had one pitted area. Hugh's method of fork tube pit repair generally follows these simple steps:

1) In my case I actually had removed the fork tube allowing him to lay it flat on his work bench
2) First clean off the offending area with a general cleaning solvent to get rid of any oil and debris
3) Using very fine emery (ie; crocus) remove any potential raised burrs, but leave the depression area of the pit as is (ie jagged)
3) Quick flush cleaning of the area again
4) Apply the flux product
5) Preheat the pit area a bit and then using a simple cigarette lighter torch melt a very small amount of the Cronabraze solder/braze wire into the pitted area.
6) Allow the area to cool and then buff the excess solder/braze material away using, again, very fine emery cloth ... buffing to a smooth finish.
7) Reassemble and cruise for many happy years of NON-leaky forks 

The cost of refurbishing and rechroming heavy duty equipment hydraulic cylinders have driven machinery companies to find simple and cost effective repairs, that will stand up to the riggers of the construction and mining industries.  Since these are certainly more demanding applications than us lightweights cruising around on our 750's ... I like the approach.   :wink:

[SCRob]

Has anyone tried this? Does it work?  Is it really that easy?

What does the stuff cost?  The site requires registration to view pricing.

Thanks,
Rob

[onepieceatatime]

The solder is expensive, when I priced it around $43 for the small tube of it. I have not done it yet, but guys on either the DOHC or CBF SuperSport forum (I can't remember which one) have done it with good result.
I'll see if I can find the post and give a link.

[onepieceatatime]

http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=66467&highlight=pitted+fork+repair

If you scroll down, there are pictures showing the repair in progress and how it looks with some of the pits filled, as well as a couple of tips.

[750resurrection]

The youtube videos look good.

Looks like it's tech they don't want the masses to have or the patents are still active and they sell at high price to medical and hig end places for lotsa $$$.