Author Topic: Fork tube repair or replacement. What are my options?  (Read 1219 times)

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Offline fizzlebottom

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Fork tube repair or replacement. What are my options?
« on: March 15, 2021, 10:48:16 AM »
Typical story. 82 CB650SC Nighthawk, enough pitting on the (37mm) fork tubes to make for leaky seals. Franks Forks has been moving shop since Sept and isn't yet back up and running. The other options I can find are hunting eBay for used sets that'll almost definitely have pits, or send them out to a chrome repair shop. Aside from Franks, every "new" set from manufacturers lists the wrong 35mm tubes because they're from other CB650 models.

I've called a few places, and the one that seems to know the most about motorcycle fork tubes is EC Grinding outside of LA. For them to strip the original finish, grind out pits, apply new hard chrome, and grind down to spec, it'd cost ~$450 for both. That's a chunk of dough. Franks would cost maybe a few $ less with shipping/tax if they were taking orders.

I've read about the temporary superglue method but I have a lot of tiny pits that I'm not really willing to risk filling only to have them fail instantly.

Am I missing any other options? Either chrome shops you have experience with, manufacturers who might have the right tubes listed, or repair methods that are more likely to work?
1982 CB650SC Nighthawk

Offline Alan F.

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Re: Fork tube repair or replacement. What are my options?
« Reply #1 on: March 15, 2021, 11:05:55 AM »
So are you looking for new tubes for less money or just some nicer used tubes? There are a few SOHC cb650 front ends lately on a few forums I read. What's your location? Maybe someone nearby has something.

Offline fizzlebottom

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Re: Fork tube repair or replacement. What are my options?
« Reply #2 on: March 15, 2021, 11:12:38 AM »
So are you looking for new tubes for less money or just some nicer used tubes? There are a few SOHC cb650 front ends lately on a few forums I read. What's your location? Maybe someone nearby has something.

I'm looking to make sure my fork tubes are of the non-pitted variety. Whether this is through replacement (new or used) or repair is kind of what I'm trying to figure out. I'm in Seattle, in case you have leads on any used sets for my application. Thanks much.
1982 CB650SC Nighthawk

Offline newday777

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Re: Fork tube repair or replacement. What are my options?
« Reply #3 on: March 15, 2021, 11:28:49 AM »
So are you looking for new tubes for less money or just some nicer used tubes? There are a few SOHC cb650 front ends lately on a few forums I read. What's your location? Maybe someone nearby has something.

I'm looking to make sure my fork tubes are of the non-pitted variety. Whether this is through replacement (new or used) or repair is kind of what I'm trying to figure out.

I'm in Seattle, in case you have leads on any used sets for my application. Thanks much.

Change your profile location so people wanting to help don't have to ask.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A


Offline fizzlebottom

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Re: Fork tube repair or replacement. What are my options?
« Reply #5 on: March 15, 2021, 11:49:24 AM »
Change your profile location so people wanting to help don't have to ask.

Changed

https://www.ebay.com/itm/1983-Honda-CB650SC-Nighthawk-H1579-1-forks-front-suspension/293828726838?hash=item44698e9036:g:uH4AAOSwHBhfpAkO

Those are for an '83 CB650, which is a totally different bike than mine. Plus they're 39mm tubes and mine are 37mm tubes.
1982 CB650SC Nighthawk


Offline Duke McDukiedook

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Re: Fork tube repair or replacement. What are my options?
« Reply #7 on: March 15, 2021, 12:21:54 PM »
http://www.fastfromthepast.com/05-0063

They say 35mm for that bike but you may be able to email them and see if that is a typo or they may be able to swing a 37mm in the proper length.
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Offline Alan F.

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Re: Fork tube repair or replacement. What are my options?
« Reply #8 on: March 15, 2021, 12:28:13 PM »
From the forums at www.vintagehondatwins.com
Located in Kitsap County, WA

Forks and triple tree only. Wheel assemblies are not for sale. Located in Kitsap County, WA. Not sure what they are worth but willing to let go below eBay prices. These look and dampen pretty nice, no leaks, no rust, no pitting.

https://www.vintagehondatwins.com/forums/showthread.php?2699-CB650K-front-end


Offline fizzlebottom

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Re: Fork tube repair or replacement. What are my options?
« Reply #9 on: March 16, 2021, 09:41:18 PM »
https://www.ebay.com/itm/Fork-inner-tube-chrome-interchangeable-to-the-original-Honda-CB-650-1982/142607445012?hash=item213410ec14:g:YTEAAOSwj99aH91d

http://www.fastfromthepast.com/05-0063

They say 35mm for that bike but you may be able to email them and see if that is a typo or they may be able to swing a 37mm in the proper length.


I discovered something interesting. I hadn't run across these before because they don't specify CB650SC. I did come across one from Omnia Racing for an 82 CB650SC for a 35mm fork tube, which is wrong. After digging a bunch, I found that nearly ever damn current fork tube manufacturer (maybe aside from Franks) has somehow mixed up the '82 CB650 / CB650C (35mm) with '82 CB650SC (37mm). I now know both Omnia & Fast From The Past have the correct diameter (37mm) for the wrong listing (82 CB650/C), but I'm unsure if it is the correct length. Guess I'll have to disassemble my forks to get the actual length so I can make the right order when the time comes.
1982 CB650SC Nighthawk