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Discussion Starter #1
So, dismantled the forks.

1970 CB350 (I'll eventually figure out how to get that into my signature)

As I said in my build log, I was surprised to find that this bike had external springs. Which makes fork rebuild super easy, but might not be the most comfortable shock absorbers. I believe I did read using 10w fork oil will help a bit for a rider under 200lbs, so I'll try that, but not looking to swap the forks out.

Anyway, the real concern here is can I reuse these fork tubes?

What's best solvent to get this build up off the chrome? Is mineral spirits always the way to go? Evap o rust?

With the lower part of the fork tubes in good condition, and where all the actual work happens, is the upper part more aesthetic then functional? I'm going to be using my NOS fork covers, so I'm not worried about how the upper part looks, just want to make sure the functionality won't suffer.

My mind says replace, but my wallet says refurbish


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As long as you're not seeing any cracks and the forks are straight, there's no reason they can't be refurbished. If it was me, I would get some naval jelly from Auto Zone, a brass brush and a Scotch Brite pad and see how much of the rust comes off, then rub some aluminum foil on the surface after you rinse all the brown residue off. A quick wipe with a little oil on a clean cloth after that should hopefully protect the surface afterwards.
 

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Discussion Starter #3
Awesome, thank you. That's the first I've heard of naval jelly, I was doing some more research and saw metal rescue mentioned as well. I'll clean them up, see what they look like under the corrosion, then measure to make sure they are straight, and go from there.

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Metal Rescue or Evaporust would work well too, but you'd have to use a container that maximized the gallon (or buy more than one gallon) and still do maybe only one end of the tubes at a time, so naval jelly might be the best shot in this case. Honda didn't chrome the upper parts of the tubes back then because the headlight ears and metal fork covers or rubber gaiters covered everything. You could spend the cash to get them rechromed, but I painted my upper tubes with hammer-finish silver and they look decent for a lot cheaper
 

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On this site, search "Barkeepers friend"
It works like none other
 

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Discussion Starter #6
Went to AutoZone, they were out of the loctite naval jelly, but they did have the metal rescue, so I picked that up. I see why you say gotta make the gallon count! $20 for a small jug of concentrate?

I am going to try that first, I saw a post on the site using PVC pipe as a soaking tub for exhaust, going to go that route for now and see what results I get.

As for bar keepers friend, I know they sell that at the supermarket, I'll pick some of that up, sounds like that will be great to de rust all these nuts and bolts, because honestly I've had stuff soaking in my parts washer filled with crud cutter, and let's just say I'm not impressed.

Thanks guys, a lot of great suggestions.

I'll post up some pics of the PVC set up and the after results when I soak the tubes for a couple of days.

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Discussion Starter #7
So here it is, 4" PVC pipe, my mom and pop hardware store sold it in a 2.5' section, so even saved some time cutting. Got a rubber quick cover for the bottom, and filled it with a gallon of water and the metal rescue. Fork tube made a perfect stirring tool, lol. Perfect fit, got both fork tubes in and under the solution. Gonna soak it for a few days and see how they come out. Then once I see how bad the pitting is, I can make a better decision on whether to replace, or keep.


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Discussion Starter #8
Here's the results, metal rescue did a pretty decent job, lots of pitting in the non chromed upper part of the tube, and slight de chroming on the one fork.

So looking for some advice

A. Use as is? Will there be performance issues?
B. Re chrome?
C. Get a new set of fork tubes?

I don't think the upper pitting will be an issue, but the de chroming concerns me.

Let me know what you think


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Discussion Starter #10
I emailed Franky forks, we will see if he even makes them for my bike. Didn't see my particular model on his list. I think everyone just swaps forks on the years where they had the external spring. We will see what he says.

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Upper portion you could polish out nicely with a strip of fine emery cloth. Oil 'em with Corrosion Block etc... and go back together.
 

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I have a 1970 cb350 and Franks Forks did not make them. That was 2 yrs ago though. Always worth an ask. Good luck
 

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Discussion Starter #13
I did find the forks on niche cycle site? $149 for the pair, full chrome. Never heard of that site before. But the pictures looked just like my tubes.....

I'll try the Emery cloth, and see where I go

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Discussion Starter #15
I ended up getting a new set of fork tubes through niche cycle. Just couldn't accept the pitting on the tubes, and the chrome flaking was just too much.

Ok, next question in regards to these 1970 cb350 front forks. I'm sticking with the stock setup, and running with the external fork springs.

I can't for the life of me find replacement fork spring guides to replace this damaged one. Even if I could find them, it seems nearly impossible to get these guides out without further damage. I ordered a spare pair of fork springs off eBay with guides that are in great shape, the springs however are a little more worn than mine.

So the question is, are there any tricks to getting these guides out?

Any suggestions are appreciated, getting ready to rebuild these forks. I think I'm just over thinking this, I mean really I'm obsessing over a suspension that has been compared to the engineering equivalent of a screen door.

Thanks in advance!



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...over a suspension that has been compared to the engineering equivalent of a screen door.
Try to remember that the suspension is older than lots of bikes that are no longer on the road today, and it was designed in the formative stages of Japanese bikes during a time when engineers used pencil, paper and slide rules, and when they went home they had to watch 4 channels and black and white TV... at least compare it to a pogo stick
 
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