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6th Gen fork tubes, 2021 edition


ShipFixer

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So next thing my resurrected 2002 needs is a fork service!  Plenty of tiny pits and the left seal has pretty much give up.  The last time it was serviced was prior to me selling it in 2011 🙃

 

Lots of old info in the forums, so...what's the best option for fork tubes today?  New from Honda is about $300 each.  Some of the rechroming or alternative sources in the US mentioned in previous threads are gone or do not have 2002 43mm tubes available...

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So far, best option I can find is TNK tubes from RaceTech at $191 each...

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If the pitting isn't too bad, Larry posted an extremely detailed post on how to removing minor pitting and polish fork tubes a few years ago.  

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Here's what they look like.  This is after getting the surface rust off with steel wool and oil a few months ago:

 

4DC8F0BD-BB8A-43C9-A769-3B410889349F.jpe

 

1C7D31B0-3DED-46DB-ACA5-8674DB345D1C.jpe

 

I've found lots of other instructions on polishing on the internet but not here on VFRD.  Obviously would rather not spend another $400 on my 19 year old bike so...how bad is this?  😄

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I’ve had stachions replated and they’ve been fine, significantly cheaper too

 

Not sure where this in relation to you but they offer the service 

 

http://framestraightsystem.com/Motorcycle Fork Repair.htm

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Just got some quotes back from places in SoCal near me.  Cost for replating here is slightly more than TNK tubes from RaceTech.  Uh...

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Any opinions on how bad my pitting is?  I think I could sand and fill the worst pits especially since they're pretty high on the stanchions.  Most pictures I found on the internet seem about the same.  I don't have any rust obviously running under the chrome, etc.  

 

Worst case is I just end up doing a fork service again a bit down the road, so...

 

Riding last night for the first time in a while, the fork definitely needs a service so I think I'll give seals and bushings a try and do the best I can on polishing the current stanchions.  

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😜As far as I can tell you do not have bumps under chrome. Some chuck stanchions into drill and wet sand with fine paper.

So you can make it work but it will always rust in the same spots. 

Not sure what it is your budget is, how about fork swap?

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Performance wise, the fork is just fine.  It still has the RaceTech compression and rebound valves I installed in 2006 or so, along with HyperPro progressive springs.  It takes square edged highway bumps better than my SUV and corners great.  But it's also a ~19 year old bike and I've already spent a lot of money refurbing away what the "in-between" owners did leaving it outside, etc.  I have other hobbies that I'm more into at this point as well.  So if I can make a really good fork work really well all over again that's fine, don't need a huge upgrade 😄

 

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I am not trying to sell upgrade. I had similar issue on my suki bike, except corrosion was under  chrome producing bumps. I looked at the prices of stanchions but bought whole gixer front end, that is bolt on mod for my bike, all for 300 bucks. 

I think you can live with the polished forks, just additional maintenance item of greasing forks together with chain lube.

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Do the seals and bushings. When they are apart, stone down any rock chips, do a light sand with SUPER FINE paper, polish back up.  If the seals leak sooner then they should, (and you're confident in your work), then you have your answer.

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4 hours ago, Magneto said:

I am not trying to sell upgrade. I had similar issue on my suki bike, except corrosion was under  chrome producing bumps. I looked at the prices of stanchions but bought whole gixer front end, that is bolt on mod for my bike, all for 300 bucks. 

I think you can live with the polished forks, just additional maintenance item of greasing forks together with chain lube.

Haha...didn't see a sell in there, assumed an honest question 😄 I've thought about fork swaps in the past when I was waaaaay more into riding.  This is when I could tell the difference between my 2002 43mm tubes and my friend's 2001 with 41mm tubes though.  Or felt like I could.  

 

I would say a front end swap for ~$300 would be an easy choice!

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My opinion - go cheap and see if you can salvage them first. Doesn’t look like the rust has penetrated deep, as others have observed. 
 

My method is to rub with aluminium foil and phosphoric acid (or Coca Cola if you can’t get some - use diet to avoid stickiness). The Phosphoric converts rust into a honeycomb phosphate coating - this stuff is TOUGH. The tinfoil breaks off into microscopic bits that embed in the phosphate layer. Scrape any big rust lumps off with razor blade. 
 

Make sure all rusty spots are blackened by phosphoric acid. If not, wash it with phosphoric acid (or Coke) again until it does. You can’t do this too much! 
 

Then epoxy any deep craters (JB Weld works great) . Don’t worry if it sticks out - deal with that later. Once cured for 24 hours, use razor blade to scrape down bumps of epoxy until it’s all level. 
 

Now rub fork oil over the surface. Phosphate coating absorbs and traps oil beautifully, making the repair waterproof. 
 

Then, VERY fine sand (I used 2000) followed by grey scotchbrite pad. Use oil as lube rather than water. Epoxy is softer than steel so will wear down even. DO NOT SAND/BUFF UP-AND-DOWN! Do it sideways. As Magneto says, chuck the stanchions on a drill and spin it to buff. If you can’t do that, throw them on a broomstick and buff like a shoeshine. This helps create horizontal ridges that hold oil and stops cutting up seals. Same idea as cylinder honing. Aim for a 45* cut. 
 

You’ll end up with slightly less mirror-like chrome and your stanchions will work great for years to come. 
 

This works even on worse rust than yours. Give it a go before you spend any real money. Will cost you less than £5 ($7?) in kit and about 2 hours in work. 
 

Good luck and post pics when you’re done! 
 

Stray

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7 hours ago, ShipFixer said:

....

 

I would say a front end swap for ~$300 would be an easy choice!

 

Deals are out there. Best if you can find someone in rust free state parting bike out. Otherwise temp fix like suggested so you can enjoy it in the meanwhile...

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15 hours ago, Stray said:

My opinion - go cheap and see if you can salvage them first. Doesn’t look like the rust has penetrated deep, as others have observed. 
 

My method is to rub with aluminium foil and phosphoric acid (or Coca Cola if you can’t get some - use diet to avoid stickiness). The Phosphoric converts rust into a honeycomb phosphate coating - this stuff is TOUGH. The tinfoil breaks off into microscopic bits that embed in the phosphate layer. Scrape any big rust lumps off with razor blade. 
 

Make sure all rusty spots are blackened by phosphoric acid. If not, wash it with phosphoric acid (or Coke) again until it does. You can’t do this too much! 
 

Then epoxy any deep craters (JB Weld works great) . Don’t worry if it sticks out - deal with that later. Once cured for 24 hours, use razor blade to scrape down bumps of epoxy until it’s all level. 
 

Now rub fork oil over the surface. Phosphate coating absorbs and traps oil beautifully, making the repair waterproof. 
 

Then, VERY fine sand (I used 2000) followed by grey scotchbrite pad. Use oil as lube rather than water. Epoxy is softer than steel so will wear down even. DO NOT SAND/BUFF UP-AND-DOWN! Do it sideways. As Magneto says, chuck the stanchions on a drill and spin it to buff. If you can’t do that, throw them on a broomstick and buff like a shoeshine. This helps create horizontal ridges that hold oil and stops cutting up seals. Same idea as cylinder honing. Aim for a 45* cut. 
 

You’ll end up with slightly less mirror-like chrome and your stanchions will work great for years to come. 
 

This works even on worse rust than yours. Give it a go before you spend any real money. Will cost you less than £5 ($7?) in kit and about 2 hours in work. 
 

Good luck and post pics when you’re done! 
 

Stray

Thanks - I think I saw your instructions elsewhere?  On Amazon it looks like I can get a quart bottle delivered.  Do you use it straight, or dilute it?

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2 hours ago, ShipFixer said:

 

Thanks - I think I saw your instructions elsewhere?  On Amazon it looks like I can get a quart bottle delivered.  Do you use it straight, or dilute it?

Depends on the concentration but phosphoric acid isn’t one of those nasty ones that burn through flesh and cause land to be contaminated forever. It’s a reasonably gentle acid (we drink it in Coca Cola!). 
 

Dilute about 1/10 and dab it until rust turns black. If it doesn’t react add more acid. Mix a small batch - you won’t need much. Then rinse well to stop it reacting. I’m told baking soda and water helps with that but I just rinsed with lots of water. 
 

You can buy rust converter which is 99% based on phosphoric acid. Or just use Diet Coke (takes much longer but does work). 

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Another benefit of phosphoric acid (compared to any other acid) it it has preferential action on rust and corrosion. It'll stop when clean metal is reached. Unlike other acids which continue to eat away at perfectly good metal as well.

 

You'll also want to do light sanding & polish to remove sharp-edges of pits. Even though there's no sharp-edges poking up, there's sharp edges around rim of pits. When seal slides over these pits, rubber will fall into pit and get gouged out if there's sharp edge on rim.

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17 hours ago, Stray said:

My opinion - go cheap and see if you can salvage them first. Doesn’t look like the rust has penetrated deep, as others have observed. 
 

My method is to rub with aluminium foil and phosphoric acid (or Coca Cola if you can’t get some - use diet to avoid stickiness). The Phosphoric converts rust into a honeycomb phosphate coating - this stuff is TOUGH. The tinfoil breaks off into microscopic bits that embed in the phosphate layer. Scrape any big rust lumps off with razor blade. 
 

Make sure all rusty spots are blackened by phosphoric acid. If not, wash it with phosphoric acid (or Coke) again until it does. You can’t do this too much! 
 

Then epoxy any deep craters (JB Weld works great) . Don’t worry if it sticks out - deal with that later. Once cured for 24 hours, use razor blade to scrape down bumps of epoxy until it’s all level. 
 

Now rub fork oil over the surface. Phosphate coating absorbs and traps oil beautifully, making the repair waterproof. 
 

Then, VERY fine sand (I used 2000) followed by grey scotchbrite pad. Use oil as lube rather than water. Epoxy is softer than steel so will wear down even. DO NOT SAND/BUFF UP-AND-DOWN! Do it sideways. As Magneto says, chuck the stanchions on a drill and spin it to buff. If you can’t do that, throw them on a broomstick and buff like a shoeshine. This helps create horizontal ridges that hold oil and stops cutting up seals. Same idea as cylinder honing. Aim for a 45* cut. 
 

You’ll end up with slightly less mirror-like chrome and your stanchions will work great for years to come. 
 

This works even on worse rust than yours. Give it a go before you spend any real money. Will cost you less than £5 ($7?) in kit and about 2 hours in work. 
 

Good luck and post pics when you’re done! 
 

Stray

What Stray says is quite true, Phosphoric acid will chemically turn Iron Oxcide (rust) into Iron Phospahate a hard black fairly inert  substace that forms a barrier that then protects the Iron substrate. 

 

I work on ships also, as crew, and we use it after we scape any rust away and wire brush the area. We brush it on and wait for it to dry, may take a day, then apply a primer then when ready a topcoat. Works the charm. 

 

I'm a rigger and on the bridge, not a painter, but I use the  it on stainless to remove rust and on my bikes for the same reason as Maine has salt on the roads 6 months a year.

 

Not sure what you do on ships, but grab a painter some day at the yard and ask them about Phosphoric acid. One of the trade names is Ospho. Readily available in any real Chandlery, or maybe they can give you a cup or so. I use it straight from the container, I mean the stuff is in Coca Cola so its not that awful. I think much like Citric acid (lemon Juice) is an acid, this is also, but fairly beniegn. Wear some nitrile gloves and have at it.

 

I'll try to include a picture.

 

Good Luck.

0320211848.jpg

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Ok I have everything on order except the JB Weld - which type do you guys use?  The steel type, or will any generic epoxy do?

 

 

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  • 2 weeks later...
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Haven't done it yet, but I suspect it will go very well 😄  I received everything I need this week, just need to set aside some time to do it. 

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I'm about halfway through this now...glad I'm going this route.  I'm doing a little differently with the epoxy since I've got a bunch of little pits rather than any big ones.  I put a lot of cleanr JB Weld all over the pitted area, let it sit for a minute, then wiped it down really well.  (Basically how I fill in minor surfboard cracks and dings without going deep into the outer epoxy shell 😄 )  First attempt it's pretty flat and passes the finger nail test after curing!  All in all, my tubes do not look nearly as bad as some other examples I've seen on the internet, so even if it's not perfect, I'm pretty happy with the results.  All of the pitting it outside of normal travel too.  Like last inch to inch and a half below the lower triple clamp.

 

Thanks for the acid/epoxy plan guys, I am going to go back and use epoxy to fill a somewhat large nick in one of my expensive mountain bike forks!  It's right in the side of it, inside of the normal travel zone and super annoying to know it's possibly killing the seals slowly each ride...

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I'm very happy with how this turned out.  Here's the before...this is six months after the last time I used steel wool and oil to knock the rust back by the way:

 

IMG_1674.jpg?width=960&height=720&fit=bo

 

After the acid, and covered in clear JB Weld epoxy.  Since I have lots of little pits rather than any big ones, and this works on other things I use it on...I covered all of the pitted area, let it sit for a minute or two, then wiped clean with paper towels.  This is the five minute variety so letting it sit longer than that gets a bit sticky:

 

IMG_1675.jpg?width=960&height=720&fit=bo

 

Then last, I wet sanded with 2000 grit and alcohol.  This is after fork assembly.  The pits look black to me (I'm really hoping none of you with normal color vision look at it and say it's still red!).  But the pits are flat under my fingernails and with a magnifying glass, so I am declaring success and moving on 😄

 

IMG_1680.jpg?width=960&height=720&fit=bo

 

Otherwise, and I knew this would be the case, the forks haven't been opened up since I last owned the bike and they were nasty.  They're still "okay-ish" on the road but pogo a bit on undulating freeways and the not-that-old front Pilot Road 4 is cupped like you wouldn't believe.  The dust seals were cracked and oil was pumping out of one side, and both forks had a fair amount of sludge in the bottom of the legs, but not inside the valves.  One of the retainer rings was corroded so some amount of water got in that side (which of course had more sludge).  

 

New bushings, seals, and flushed out RaceTech compression and rebound valves are going to feel pretty good!  It's bugged me since I got the bike back, since my last memories of it were the several thousand miles that came after I installed the upgrades.  

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