re-chroming fork tubes

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pumpguy
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re-chroming fork tubes

Post by pumpguy »

Does anyone know of a good supplier in the USA, preferably in the Midwest, to have a set of pitted fork tubes repaired with hard chrome and ground back to size? This is not for my KDX, but for a '65 Maico, and those tubes are made of unobtanium.

I am aware of Franks in Evanston, IL, but he says he's having trouble getting this done, and isn't taking any tube repair work now, only new tubes. I have also contacted firms that repair hydraulic cylinders, but so far, they have either flat out said no, or quoted a not-so-small fortune, or said "we'll get back to you" .

Replies from anyone with personal experience would be greatly appreciated.
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re-chroming fork tubes

Post by sarrant »

I have no experience with it, But two names I have seen online in vintage circles are Gary's Grinding in Ontario, CA and United Surface Finishing in Canton, OH.
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re-chroming fork tubes

Post by pumpguy »

Thanks,

I'll give them a call and see what they say.
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re-chroming fork tubes

Post by pumpguy »

Checked with United Surface Finishing and was told their final operation after plating is surface polishing. They do not grind the OD to size, and estimated their tolerance is in the range of .002". That's too much for me. I'm looking for something in the range of .0005".

Electronic Chrome and Grinding in Santa Fe Springs, CA. does finish grind to size and said they can hold OD tolerance to .0005".

Also talked to the cylinder plating folks Millennium Technologies. Was told they don't do this right now, but are seriously considering offering this service. Was advised to check back in a few months.

Talked to a few hydraulic shops, but prices quoted are almost double what Electronic Chrome wants.

Still have to check with Gary's.
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Re: re-chroming fork tubes

Post by KDXGarage »

What kind of price did they quote at Electronic Chrome?
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pumpguy
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re-chroming fork tubes

Post by pumpguy »

Electronic Chrome, $150-225 EACH LEG, plus 15% hazardous waste disposal surcharge.

Gary's, $500 PER SET.

Both finish grind between centers to .0005" or less tolerance.
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Re: re-chroming fork tubes

Post by KDXGarage »

OUCH! At least it is for a good cause.
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re-chroming fork tubes

Post by pumpguy »

I agree.

I have some contacts in Germany that might be able to provide new replacements, but don't have much hope.

Looking into cosmetic/DIY alternatives. These include Devcon 5 minute epoxy on the internal pits and thin wall stainless steel shrouds over the tubes in the exposed area between the triple clamps. McMaster Carr has just the right size thin wall stainless tube for this job.

I would have discounted the epoxy route, however a couple years back I was using it to coat an ignition coil and had some drip down onto the sheet aluminum chip tray between the ways on my lathe. I had just wiped off the chips and oil from the tray, but not with any type of degreaser. Well, that epoxy is still there, it is stuck permanently.
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Re: re-chroming fork tubes

Post by KDXGarage »

I remember reading a Classic Motorcycle Mechanics magazine where some shop in the UK was doing hard chrome (Philpots maybe??)

It looked interesting.
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re-chroming fork tubes

Post by pumpguy »

Yes, there are a good number of firms in the UK doing this and many other forms of specialty motorcycle restoration work. I'm just afraid of sending some irreplaceable parts half way around the world. That's an awful lot of distance for stuff to get lost or damaged. It's a shame we don't have as many of these firms available to us here in the USA.

Back in the day I used to get some real bargains on bike and sailboat stuff from England. But we had a real strong dollar then too.
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re-chroming fork tubes

Post by scriberman »

I've had crankshafts hard chromed and ground buy these, http://www.sep-kegworth.co.uk/page1.htm
Not sure if the do forks.
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Re: re-chroming fork tubes

Post by fuzzy »

.002 isn't good enough? Your specs are like the difference between an A and B piston inside a cylinder. .002 is less than a hair, for fork tubes would think it would be OK?
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pumpguy
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re-chroming fork tubes

Post by pumpguy »

Hair thickness just depends; some are thicker and some are thinner. IIRC, piston letter dimension differences are in the 10th of a thousandths range, .0001".

I have a machinist background and used to do finish grinding work for a living. As as result I have pretty high standards.

Just polishing after plating won't insure uniform diameter and roundness along the whole length of the tubes. This may be acceptable for some, and may work OK when everything is said and done, but IMO, is somewhat cosmetic and not a workmanlike way to do it.
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Re: re-chroming fork tubes

Post by pumpguy »

Just talked to United Surface Finishing, and learned they discontinued rechroming motorcycle fork tubes about a year and a half ago.

He who hesitates....
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Re: re-chroming fork tubes

Post by bufftester »

Yeah, chrome plating is becoming less and less common due to the EPA folks, something about chromic acid being all carcinogenic and stuff. Here in Washington most of the small platers have gone away from hard chrome and towards nickel alloys and HVOF.
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Re: re-chroming fork tubes

Post by Chuck78 »

I just stumbled upon this thread when looking into the feasibility of having this exact operation done, as I got a pair of the fabled conventional cartridge 49 mm Showa Twin Chamber 96-98 RM125 forks for a deal at $188 on eBay with "excellent chrome and in good usable condition," well you know how eBay sellers are... most of them aren't terribly familiar with the mechanics, they are just employees who strip parts, and it ended up having 10 or so rust pits that make the chrome not usable... Unless I were able to successfully acid etch the pits and use some JB weld or other epoxy to try and make them work...
I did find another set of good chrome tubes for $180 shipped, but they have some pitting between the triples, hopefully that's not a sign that the seal travel area will have rust pitting develop in the near future.

Each year of these forks 96, 97, and 98, although appearing very similar, or identical in case of a 97 and 98 on the exterior, they all are fairly unique on the insides with enough different systems to make most parts not compatible. I might pick up a second set of 98 forks.

This is what a quick internet search led me to, besides this thread:

https://www.ecgrinding.com/motorcycle-fork-repair.html
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, etc, '99 KDX220R awaiting rebuild & mods, '77 Suzuki PE250 restomod project, '83 Suzuki PE175 Full Floater restomod project, '77 Suzuki GS750-844cc, '77 GS400-489cc racer project, '77 Suzuki GS550/740cc project, '62 GMC 1000 Panel Truck, '88 Suzuki Samurai TDI/Toyota swaps, '88 Toyota 4x4 pickup
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