Bent front suspension

[deezy]

Hey everybody, this is my first thread!! I just wanted to put this out there and get some ideas from you guys. I have a Honda ct70k1 that I am fixing up. the front forks seem to be bent, and I am not sure what to do. I don't want to spend a bunch of money on another pair but I don't see how I can fix them. Is there a way to bend them back? If not then should I get aftermarket or used replacements? I was able to find a listing on ebay for new aftermarket shocks and I am wondering wether they would be of good quality? Heres the link:
CT70 Ct 70 Front Forks Shocks Fork Set Assembly Suspension V FK10 | eBay

Thanks!

 

[cjpayne]

The add says they're the same specs and QUALITY for $82.40. IMO, sounds to cheap for high quality parts and the finish on the lower forks looks terrible to me, compared to the OEM's. I'd be leary. But who knows, they may work great. Suspension parts BETTER work great, since it's your life riding on them.

 

[OLD CT]

Axle bolt holes are smaller,just from the pics...

 

[scooter]

Deezy - I'd dig in a little more and figure out what is bent. Probably the center tube is bent. If you get them apart, take the clips at the bottom off and remove the aluminum bottom sleeve. Then roll the tube on a flat surface and see how far they are out. If the chrome isn't warn from being bent straightening becomes an option (step 2). First thing is to figure out what's wrong

 

[deezy]

Deezy - I'd dig in a little more and figure out what is bent. Probably the center tube is bent. If you get them apart, take the clips at the bottom off and remove the aluminum bottom sleeve. Then roll the tube on a flat surface and see how far they are out. If the chrome isn't warn from being bent straightening becomes an option (step 2). First thing is to figure out what's wrong

Thank you scooter, looks like the tube is 2mm out and the chrome is still good. Not sure how bent the second one is because its currently frozen/stuck in the bottom sleeve.
From the looks of it though I think I can straighten both of them. Any advice on how to do that? I am thinking that I am gonna need a jig and a jack?
Thanks everyone for the help!

 

[kirrbby]

I've been experimenting with straightening one of these fork legs recently. The inner leg (tube) is still available new, off the top of my head I think they are $90 each. I was able to get one reasonably straight yesterday using a big vice. They are really tough. A hydraulic press would probably be the right tool for this job. Not many would have a big enough vice to bend one back. I made a jig of sorts out of ¾" plywood pieces so as not to damage the tube. I first tried it with 2" wide pieces and that was too wide. I ended us shearing the 5/16" pin that secured the vice handle. I then cut a piece 1¼" wide to use in the center, right at the high spot of the bend. Still took a LOT of pressure but it worked. I had to overflex the tube maybe ¼" or so to get the kink straightened out. The vice I'm using is really made for woodworking so maybe a regular vice might work easier/better. This vice is about 12" wide and has a 12" long handle. The 2 outside blocks of wood are about 10 apart (between) multiple tries to be sure not to overdo it. Mine is not perfectly straight now but its close, and I think close enough. The tube I started with was at least 2mm out, maybe 3.

 

[scooter]

Kirby - they're tuff. I use a press, some tooling and some good measurement tools. Good luck

 

[scooter]

Thank you scooter, looks like the tube is 2mm out and the chrome is still good. Not sure how bent the second one is because its currently frozen/stuck in the bottom sleeve.
From the looks of it though I think I can straighten both of them. Any advice on how to do that? I am thinking that I am gonna need a jig and a jack?
Thanks everyone for the help!

Probably stuck because of the bend. Keep pounding it against the seal. I'll try to write something up on how I measure and set it up in the press. May need to do a sketch

 

[kirrbby]

Kirby - they're tuff. I use a press, some tooling and some good measurement tools. Good luck

Tuff is right! I was definitely impressed at just how tuff they are. If you are able to straighten them and willing, for a reasonablefee of course, it would be a very good service for us. Amazingly, there seem to be quite a few that get bent.

 

[deezy]

Probably stuck because of the bend. Keep pounding it against the seal. I'll try to write something up on how I measure and set it up in the press. May need to do a sketch

Thank you guys for all the great help!! That would be awesome!

 

[deezy]

Thank you Kirrbby, I am gonna see if I can do it with my 4 inch vise:42:. I am not sure if it will work, I might need to find a strong metal support to put behind the wood so it doesn't flex. Its definitely worth a try, especially if it would save me from buying another set.

 

[kirrbby]

Thank you Kirrbby, I am gonna see if I can do it with my 4 inch vise:42:. I am not sure if it will work, I might need to find a strong metal support to put behind the wood so it doesn't flex. Its definitely worth a try, especially if it would save me from buying another set.

The vice I used was a serious tool, and I pushed it to its limit. Even my limit. I cranked on the 12 inch long handle with all I had, 2 hands pulling and one foot pushing... no BS. I really, really doubt a 4" vice will have a chance.

 

[cjpayne]

Cheater pipe?

 

[kirrbby]

On my first try, with the 2" piece tryin to push out the bend, just as my workmate came around the corner with a cheater is when I broke the pin in the handle of the vice with my bare hands and booted foot. lol He just turned around and took the pipe back.

 

[scooter]

Here are some comments and a few pictures. I'm using a bent handlebar to exaggerate the setup. First if you lay the tube on a flat surface it will roll such that the plane of the bend is parallel to the surface. Mark this plane on the tube with a sharpie.

Next figure out where the bend starts using a straight edge and make a mark.

Call it "a" and do the other end call it "b"

Rotate the tube 90 degrees such that the high spot is up. You'll see the line where you marked the plane of bend. Midway between line "a" and "b" call it "c" where it intersects with the line that marks the plane of the bend is where you want to apply the load. Points "a" and "b" are where you want to support the tube. This way the straight ends remain undistorted and the bending is centered on where the tube is really bent. As the distance between "a" and "b" gets shorter the force to yield the tube goes up.

Try to make your support structure at "a", "b", and "c" distribute the load so you don't put a dimple in the tube or take it out of round.

I measure while loading the tube in my press to get within a couple thousandths. But it's very easy to see a small gap when you roll the tube on a flat surface. If you do it by trial and error.

If you're going to bother you need to spend some time working your setup. As I mentioned earlier I built some jigs both to support the bar, distribute the load, and support my measurement tools.

Good luck to those who try. Hope this helps some and makes sense.