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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Discussion Starter · #1 ·
Anyone in the Twin Cities have a portable torch kit, and interested in playing "Straighten-a-Frame?" I've got the vise and the levers. I just need a fire source.



This is the victim:







The right tube (left in the picture above) of the triple spine is bent, and the head tube twisted.







I believe that if we apply heat and leverage in the right places, the spine tube can be straightened, causing the head tube to untwist. I had resigned myself to leaving this for Spring, but after recently acquiring a front end, I'm eager to make some progress.



Any takers? If others want to help, too, we'll order a pizza and make a party of it.



R
 

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That's the way it works. Lots of heat and some good leverage. Remember just a hair over and it will pull back to the intended mark. I straightened my share of cars using this method.



That top picture makes it look like it needs a good pull to the left but pictures also lie.
 

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I'm to far away. I looked again. Have it pressed? In a machine shop on a hydrolic press. The heat would expand the tube I think to much.

I have had frount forks done that way,cold. The metal is stretched and by pressing cold that may aline the frount and the back of the frame by compressing.

My thoughts. nice pictures.

Nice looking stator! Mine on the 81 was very dark epoxy. The one in my 81 now looks like yours.
 

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Discussion Starter · #4 ·
That top picture makes it look like it needs a good pull to the left but pictures also lie.
The center tube is straight, as far as I can tell. Because of the twist, the bracket at the bottom of the head tube is displaced to the right (left in the photo.)



R
 

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Discussion Starter · #5 ·
Have it pressed? In a machine shop on a hydraulic press. The heat would expand the tube I think to much.

I have had front forks done that way,cold. The metal is stretched and by pressing cold that may align the front and the back of the frame by compressing.


I'd be very hesitant to try to straighten it cold for fear of causing cracks in the welds. You can cold press a fork tube because there are no welds. And even if the right tube ends up a little longer, it can retain a little dip, as long as the head tube it straight. I doubt it will be noticeably different.



Nice looking stator! Mine on the 81 was very dark epoxy. The one in my 81 now looks like yours.


I haven't applied a meter to it yet, so I don't know the actual condition. When this project reaches final assembly, I might mount a higher-outpur Goldwing stator, and put this one in my Ignitech-sparked CX.



R
 

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Why not get a new frame? Simpler and you don't have to worry about it being a little "off".
 

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Discussion Starter · #7 ·
Why not get a new frame? Simpler and you don't have to worry about it being a little "off".
First, I'm too cheap to throw something out if I can make it work.



Second, it's hard to find just a frame, and I don't have the space for yet another parts bike. Oh, and I'm cheap.



Third, it will be an interesting challenge. And did I mention, I'm cheap?




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Randall, I don't have the heavy duty heat source here in the city you are looking for but I do have the engine that David delivered to deer camp for you.



Speaking of deer camp, my brother-in-law does have an acetylene tourch 150 miles away in Wisconsin which you could use. I will be driving up there sometime this weekend to winterize my place. I don't remember how to use the torch but if you know how to, you may. He won't be any help either because they are in Alaska visiting their grandkids for Thanksgiving.



But, I am totally serious, we could load up the frame into my Blazer and zoom up there if you want to. It's a three hour drive one way, plus it takes me a couple of hours to drain everything down, plus I might try to shoot another deer while there. If you didn't want to wait for me to hunt, you could drive yourself and I will help you when you get there.



send me an email and we can talk about it.



Wayne.
 

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Randall, I don't have the heavy duty heat source here in the city you are looking for but I do have the engine that David delivered to deer camp for you.



Speaking of deer camp, my brother-in-law does have an acetylene tourch 150 miles away in Wisconsin which you could use. I will be driving up there sometime this weekend to winterize my place. I don't remember how to use the torch but if you know how to, you may. He won't be any help either because they are in Alaska visiting their grandkids for Thanksgiving.



But, I am totally serious, we could load up the frame into my Blazer and zoom up there if you want to. It's a three hour drive one way, plus it takes me a couple of hours to drain everything down, plus I might try to shoot another deer while there. If you didn't want to wait for me to hunt, you could drive yourself and I will help you when you get there.



send me an email and we can talk about it.



Wayne.
 

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Discussion Starter · #11 ·
Doh! The stuttering forum strikes again.



It's been kind of slow loading lately. I suspect the browser makes repeated attempts to load when the source server times out, resulting in multiple posts.





Randall, I don't have the heavy duty heat source here in the city you are looking for but I do have the engine that David delivered to deer camp for you.
David said he'd try to send it via WayneFreight, but I hadn't heard anything for a while. Thanks for carting it. I'll shoot you an email to arrange pickup.





Speaking of deer camp, my brother-in-law does have an acetylene tourch 150 miles away in Wisconsin which you could use. I will be driving up there sometime this weekend to winterize my place.
Unless you have a heavy vice at the cabin, I think it would be difficult to do up there. That's why I'm looking for a potable rig, so we can do the bending on my bench.



Plus, my weekend is already pretty full, as it is. My wife likes to pick up extra hours whenever I have time off, and the 1-1/2 year old (nicknamed Curious Georgette) needs constant supervision/rescue. Her older sisters will provide that for all of 3 seconds. (So why don't I get anything done around the house?)





I don't remember how to use the torch but if you know how to, you may.
I'm hoping to borrow some expertise, too. I've only used my brother's a couple times, and I have about enough skill to burn down the garage.



I just had a thought -- maybe I could rent a portable rig. If I can, does anyone without a torch want to come play with fire? (I'll need a few guys to form the bucket brigade when the garage goes up.) It won't be this weekend. Next is probably out, too. Hmm... it'll probably be spring before it happens, after all. I'll let y'all know if I find a opportunity.



By the way, Wayne, how was the opener?



R
 

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I don't know if heat would be the best idea or not,,,the bend in the rail is a long gradual bend. If you heat it it will bend where it is heated,,even if you heat the whole rail until it is cherry red, it will bend where you pull from. This probably will not put the steering stem back into place, you will probably have to heat the stem and try to get it straight.

Another problem you may have is that if you get it hot enough to bend, it may deform the rail where you apply the pull. You would need some kind of half tube shape to fit over the rail so it would not deform or flatten the rail.

I think a hydraulic ram may be a better option,,I would be tempted to take it somewhere that straightens frames.

I guess you can try to do it yourself, if it works, great,,if it does not then you will just have to get another frame. Didn't David have a titled frame a while ago?
 

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I've never have used heat bending frames.



I do use "come a longs" Pipe wrenches, and long persuaders... Lot's of gentle small increments with the frame in a jig (vise
) On a frame with this much distortion, I'd take it to a Racer/Fabricator friend here and have him do it on his frame table.



Eyeballing the head angle is something I would not do as the effect of a twist here can increase geometrically at speed... going from a slight wobble to a big shimmy real fast. I just would never feel confident in my "Eye" nor the bike.



IF the welds crack, they were probably already cracked or on their way to being cracked
and at least you can Re-weld them. High Carbon steel will become weak around the weld if too much heat is applied. You could destroy the frame real quick using a torch.



My .02 HTH








Reading Material... http://www.custom-choppers-guide.com/bike-building-tips.html
 

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I have to agree with Jeff about the jig and not sure just heating

one part and bending it would be satisfactory or safe.

You really need to be sure the headstock is correctly aligned with the rest of the frame
 

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Discussion Starter · #15 ·
I don't know if heat would be the best idea or not,,,the bend in the rail is a long gradual bend. If you heat it it will bend where it is heated,,even if you heat the whole rail until it is cherry red, it will bend where you pull from. This probably will not put the steering stem back into place, you will probably have to heat the stem and try to get it straight.

Another problem you may have is that if you get it hot enough to bend, it may deform the rail where you apply the pull.
The right-side tube of the triple spine is clearly bent in one spot. My plan is to heat it there, and heat the center spine closer to the steering head tube (not where my prybar will contact.) The main tube is twisted, rather than bent, and I want it to untwist below the head tube mountings, so as not to jeopardize the welds in that area. I'd like to avoid prying inside the head tube, but if straightening the right-side tube isn't enough, I'll try it. The correct size pipe in the head tube, and enough heat in the right place on the center spine should let me twist it without deforming the head tube. And I think the secondary spines will tend to align the main spine enough that it won't be distorted.





You would need some kind of half tube shape to fit over the rail so it would not deform or flatten the rail.
That's a great idea! You're correct that the lever will need to contact the right-side spine right where the heat will be applied. I can cut a short section of iron pipe in half to cradle that tube.





I think a hydraulic ram may be a better option.
The closest I can get to that would be pressing the bent right spine in the wide jaws of my vice. But heated, it would tend to flatten the tube. I've straightened lots of things that way without heat, but none of them were this heavy or needed to be this precise.



I'll give it a try, and if it doesn't work out, I'll just have to find another frame (maybe with a title, too, and save that headache.)



The frame David had was from a 650 (CX or GL, I don't remember.) Otherwise, I'd have driven to Appleton to buy him a pizza.
(If he hasn't taken you to Stuc's, you've really missed out.)



R
 

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Discussion Starter · #16 ·
I've never have used heat bending frames.



I do use "come a longs" Pipe wrenches, and long persuaders... Lot's of gentle small increments with the frame in a jig (vise
) On a frame with this much distortion, I'd take it to a Racer/Fabricator friend here and have him do it on his frame table.



Eyeballing the head angle is something I would not do as the effect of a twist here can increase geometrically at speed... going from a slight wobble to a big shimmy real fast. I just would never feel confident in my "Eye" nor the bike.



IF the welds crack, they were probably already cracked or on their way to being cracked
and at least you can Re-weld them. High Carbon steel will become weak around the weld if too much heat is applied. You could destroy the frame real quick using a torch.



My .02 HTH








Reading Material... http://www.custom-choppers-guide.com/bike-building-tips.html
Thanks for the frame-building link, Jeff. It was an informative read.



It seems I haven't considered the annealing affect of heating the frame. I had assumed with mild steel it wouldn't produce much of a change beyond removing any work-hardening introduced during the crash. Before I go the torch route, I'll try working it cold.



I won't be eyeballing anything. As I did in my initial examination, I'll be comparing a level placed on the rear engine mounting bolt to a lever placed across the end of the head tube. Even if it's a little off in between, this should keep all the running gear in alignment. I won't be able to check actual wheel alignment until I've completed some initial assembly.



Thanks, all, for your input. You've likely saved my some headaches.



R
 

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By the way, Wayne, how was the opener?



R




Pretty good, five deer on the meat pole from four hunters. Mostly young-uns though. Nothing with any antlers. David shot the biggest deer, a nice size doe.



At least we have some venison this year.



thanks for asking.
 

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Pretty good, five deer on the meat pole from four hunters. Mostly young-uns though. Nothing with any antlers. David shot the biggest deer, a nice size doe.



At least we have some venison this year.



thanks for asking.


How many are you allowed per hunter? Here you only get one.
 

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How many are you allowed per hunter? Here you only get one.




It depends on the season and if you draw antler-less permits. My dad got a michigan 6er on opening day. My neighbor got a wisconsin 6er and when he finished drinking it he had someone pick up more.



But my dad said it was a tight six so he wasn't as happy as the previous years with bigger racks. It's a meat deer not a wall deer. Oh then he said he was done and went fishing.
 

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How many are you allowed per hunter? Here you only get one.


It depends, some zones in Wisconsin have practically unlimited doe permits. Some zones, you only get one buck, period. The zone where my huntin' shack is located is still selling doe tags over the counter. Register a deer, buy another tag if you want to.

The state makes an educated guess as to the deer population in each zone and sets the doe tag numbers annually.

No matter where you are in the state though, a hunter can only shoot one antlered buck.



Wisconsin is a perfect storm for deer populations. The whole state is excellent deer habitat. The state has the largest herd of whitetails in the nation and every year hunters shoot the highest number of deer.

Of course, this is why most of us are scared to ride there after the sun goes down...
 
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