KX Riders
Maintenance & Technical => KX500 Original => Topic started by: Mhardee on September 03, 2007, 01:50:27 PM
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Got a rock ding in upper part of 2003 KX500 pipe and a log ding on the very bottom. Anybody had good results in pipe repair? A shop near Memphis?
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http://www.piperepair.com/
I have read a lot of good reviews for these guys. I have not personally used them.
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I have a premo stock pipe and a FMF Gnarly pipe for sale!
Alan :-D
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I have heard of various ways to straighten out dents in pipes. The first way involves heating the area with a torch and pressuring up the pipe and popping out the dented area. :? :? I'm not sure how you would seal up both ends to apply the pressure. The second way would be like popping out a dent in a car, by drilling a small hole in the area and using a slide hammer to pop out the dent and then welding up the hole.
Anyone else have any other ideas?
Alan :-D
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You can use freeze plugs to plug each end. I have a friend to has a schraeder valve in the middle of one so he can use heat and compressed air to get the dents out.
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Hi All
plugging the ends of the pipe and using air pressure or heat to 'expand' the dent out works great......but a bit of a heads up
heating a chamber with trapped air can be dangerous. the air expands to the point where if something fails or is torched thru the whole thing can go 'BOOM'....actually i have never seen/heard anything more than a decent 'pop', but holy cow that was enough!!
instead, fill the chamber with water and as little air as possible. the water will expand enough to force out dents, but not enough to pop. any failures result in a 'pisser' until the pressure balances out
for whatever it is worth
Mark
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Hi Mhardee
A friend of a friend who lives nearby has jigs set up for pipe repair. I had him extract several. He has some type of plugs for the ends, pressurized it with air and gently heats the area. This works perfect. The surface was only slightly discolored but the dents were gone. I am sure there is someone near you who has perfected this craft also. I am grateful this guy lives close and only charges $25.
I have seen adds in magazines for pipe repair too.
John
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instead, fill the chamber with water and as little air as possible. the water will expand enough to force out dents, but not enough to pop. any failures result in a 'pisser' until the pressure balances out
I've poped dents many pipes, in fact I made some trick adapters to plug the ends of the pipe, even though I've always been leary of the blow up, and as such I tried the process described with the water, it was the only time I've had a pipe rupture. The water dissipates the heat, once you have enough heat to expand the dent the water is so hot it turns to steam and expands rapidly and ultimately I had a hole. I work in the Industrial gas business and have a real appreciation for what compressed air/gas can do which leads to my healthy respect for the possibility of a failure, always wear gloves and safety glases, I even use a leather welding jacket wrapped around the pipe except where I'm working.
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Don46
so no problems with just air??
hmmmmmm
Mark
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Think about the expansion rate of air, OK now think about the expansion of water. To get the dent out you have to get the area hot enough to make the metal pliable, and in doing so the water gets hot enough to boil at the are being heated, turning to steam and since you have no room to expand because of the water the pressure rises rapidly. I thought this was a good idea as well, if there was a rupture it would be hydralic rather than pressure leak. I think there is the poetential for failure using air as well, I haven't had a problem.
I have heard of water being used, but rather than heat the pipe is put in the freezer, when the water freezes it expands and pops out the dent.
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Water expands 1600 times when it is converted to steam. Seems like that would be a good way to pop out a dent. Just learned that the other day reading this article about a 6 stroke engine this guy developed.
http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060227/FREE/302270007/1023/THISWEEKSISSUE
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I have also hear that the freezing method works too. You'd have to have a big freezer!
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Water expands 1600 times when it is converted to steam. Seems like that would be a good way to pop out a dent. Just learned that the other day reading this article about a 6 stroke engine this guy developed.
http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060227/FREE/302270007/1023/THISWEEKSISSUE
The idea of using water is to minimize the air volume trapped in the pipe, if a rupture occurs there is minimal energy. As you say water expands 1600 times, where does the volume go? BOOM
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if water expands 1600 times, then the calculation should be pretty streight forward.
total volume the pipe can contain /1600=how many ml of water to use to fill the space with steam upon liquid to gas change.
taking into consideration the displacement of the volume the dent subtracts from what the total volume would be. possibly by filling the dent with water from a syringe on the outside for estimation.
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I think you are going to wind up with a big split in your pipe before you ever pop a dent using the freezing method. The ice is going to apply pressure to the whole pipe equally not just the dent. Messing with steam sounds dangerous to me. (like mentioned before) What I have thought of but have never tried Is putting plumbers plugs in the pipe, one with a schrader valve. Then pressurize the pipe with a inert gas like Argon to about six psi then heat the dent with a torch until It pops out. I think using air definitely runs the risk of explosion do to the gas and oils inside the pipe. I have successfully welded gas tanks by purging them with Argon while welding.
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i think you're right on point there BDI. the pipe is almost the same as a petrolium holding vessel considering the stuff that runs through there all the time. the inert gas will work to fill the chamber safely lowering the explosion danger when you heat the pipe from the outside. however, if you only have small dings is it really worth it to risk life and limb to remove small dents? a couple hundred $ for a new pipe seems like a good buy compared to what could happen when pressurizing with air or some of the other things i've seen mentioned in this thread. by the way, if you use the method described by BDI, fill the pipe with inert gas then heat your dinged area if it doesn't pop out then while still hot, place a piece of ice in the center of the ding. the rapid cooling of the small area will shrink it thus popping the ding out while the rest of the pipe around the ding will remain in an expanded state till cooled off. i've done this with hail dents on an old truck i used to have, done on a 100 degree plus day and ice on the hail dent. worked great. MADDOGGY
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I read somewhere that guys have been using frozen water to undent their pipes. Basically fill the head pipe with water and prop it up in the freezer. The frozen water expansion pushes out the dent. I haven't tried this myself yet. Cam.
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I read somewhere that guys have been using frozen water to undent their pipes. Basically fill the head pipe with water and prop it up in the freezer. The frozen water expansion pushes out the dent. I haven't tried this myself yet. Cam.
I'm scared to try it I think the forces would not just push on the dent but rather the whole tube and could split it open like a beer can.
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Yeah you would think so. I think what happens is that the round pipe is quite strong and contains the force but the dent gets bulged back out until it matches the round. I would have to test it on an unimportant header pipe first. The air pressure, plugs and heat is a tried and true method. I would certainly feel more comfortable since it is also a controlled thing (with you controlling it). I am planning to fab up my own kevlar header pipe guard. Hopefully it can handle the heat since it is more than a 2-stroke pipe. Cam.
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http://www.rino-racing.be/cat/ (http://www.rino-racing.be/cat/)
Then page 224/225 of the Catalogue.
Have one at home and works great. Easy to make self.
Save way is to first heat the pipe, than pressurize the pipe.
Dutchie
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I would have to see the freezing method first hand to believe it. Think about it, how does the water know exactly where to push out the dent????
The air/torch method pinpoints the dent for precise removal.
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It works. The ice quickly contracts the metal that is only held in the dent by the slightly stretched metal around the dent. In a body shop they use a shrinking hammer that looks like a waffle iron on the face. It tightens the stretched metal by putting a bunch of small dents in the same area. It actually doesn't fix it, but makes the dent shallow as possible for bondo or in the old days, lead. Hail damage or that size of dent is often fixed with this method of heating and cooling.
The torch spiraling into the dent also will work. Then you need to put cold water on it to keep it popped out. At least thats how it works on body work. Sometimes it will make the dent pop up too high and you need to file or hammer and dolly back to shape.
Its been my experience that dents thay can be fixed like this are very minor dents. Ones that would only matter, if they were on your hood of a new truck. Tiny dents on the pipe probably don't affect performance as much as they take away from the look of the bike. Dents that are real big have stretched the metal enough to stay distorted and the best you can hope for is to help it.
I like the heating and cooling methods that I recently discovered that helps setting gears and tight tolerance bearrings. Heat the outside or housing, freeze the bearring or inner gear (clutch hub) and pieces seem to fall into their place without a press.
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Sorry, still not sold on the freezing method. I call BS on that.
Using water during autobody repair does not keep the dent out, it keeps the panel from warping around the work area.
The "dents" your referring to sound more like DINGS. A dent to me would be a good WHACK with a baseball bat. Dings I can live with, not dents. I have formed many pieces of metal by hand, there are many ways to remove dents and dings. Heat will help return the molecules to their original state.
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I agree, "dings." Like hail damage. Have you watched paintless dent repair on hail damage? I agree too, that any dent big enough to cause performance problems would be tough to fix. Maybe you could make it better, and what's to lose if it doesn't work? It seems obvious though that heat alone wouldn't help or they would pop out while riding.
I've heard about some local guys pressurizing their pipe with air pressure and popping out dents in aftermarket pipes, but think stock pipes would be also tough. Plus you would probably need to weld up a crack 1/2 the time on a sizeable dent. This is just evryone's first thoughts when you put the first dent in a new pipe.
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The stock four stroke end caps are made out of two pieces then epoxied together. A buddy of mine gave me a brand new muffler off of a 07 crf that was taken off at his shop because the end cap had a dent from shipping.To put it on my 05 crf450x I had to move the lower mount 10mm. What I wanted to show is the end cap. I took it off fixed the dent and welded the end cap together. I blended the welds and refinished the end cap so that it looked like it was made as one piece.This is the end cap before dent removal, after dent removal,after refinishing and then after welding.
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The dent I just fixed in my pipe was a half inch deep and you can't even tell it was there and I just fixed my buddies pipe that was smashed over two thirds.When I was done it still had all the scratches in it from the rock that smashed it flat but it was round and usable again. All the theorys and speculations are a crack up. I just go ahead and fix them stock after market stainless titainium or other.
:lol: :lol: :lol: Obviously, you have pics about fixing them and I'm talking about some guy I know that knows somebody. At least I start with "I think" sometimes. Looks good BDI. Too bad you don't live closer, I have a PC platinum with nice one to fix.
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You know what sucks I do stuff like this all the time but I never think about taking pictures. I'm going to do a two stroke pipe soon and I will show my home made tools and before and after pictures So it will be a productive post.You know lots of people have posted this ice thing lets try it doesn't any one have something to try it on find a piece of tubing smack it with a hammer and do it and post it. I looked around and I do not have any thing right off hand. I would like to see less talking and more doing. We need to do some myth busting around here. Some one could screw up his pefectly saveable pipe trying stuff like this.