The subframe is designed to hold a lot of weight (another passenger), so I don't think you are going to be able to straighten it with a bar/lever while it's still on the bike.
Tips on straightening subframe?
so I picked up a 2010 zx6r the other day off auction. not too much damage, broken fairings, left clip on and rearset... small stuff. After pulling all the tail fairings I could see that the subframe is twisted counter clockwise a bit and bent to the right a bit as well. I was reading up about this and looking for videos but couldn't find too much about any specific techniques people have used. I was thinking just slide some sort of lever through and start bending away at it until it looks straight, but was wondering if anyone on here has any experience with doing this, or can link a video of someone displaying straightening techniques. Sort of want to stay away from buying a used straight one. I figure I don't ever really have passengers (honestly I wasn't planning on putting the passenger pegs back on :tounge2: ).
Long post, sorry:crazy.
Thanks!
Long post, sorry:crazy.
Thanks!
1 - 10 of 10 Posts
I've seen some success with laying the bike over on the opposite side and doing basically a simulated drop. Take all of the rear fairings off and set something sturdy underneath on the side of the bend. Gently lean it over onto the blocks you setup and apply some pressure to try to bend it back the other way.
Do this wrong though and you'll make a double bend which looks worse. You gotta have some sense about how metals bend in order to know where to place the blocks and how much pressure to apply. I've seen this used as a last resort just ahead of buying a new sub-frame. It's not perfect, not even close. It's tricky and far from anything scientific. You of course have to bring some friends to help lean the bike on its side and pick it back up.
Do this wrong though and you'll make a double bend which looks worse. You gotta have some sense about how metals bend in order to know where to place the blocks and how much pressure to apply. I've seen this used as a last resort just ahead of buying a new sub-frame. It's not perfect, not even close. It's tricky and far from anything scientific. You of course have to bring some friends to help lean the bike on its side and pick it back up.
Heat is the key.... A bar to bend and some carefully placed heat will help. Or you could pick up a good used one on eBay for about $200.
FRAME-COMP,RR,RR
32160-0398
$175.39
Brand new retail......... just buy new unless it really isn't that bad
32160-0398
$175.39
Brand new retail......... just buy new unless it really isn't that bad
FRAME-COMP,RR,RR
32160-0398
$175.39
Brand new retail......... just buy new unless it really isn't that bad
Heat is the key.... A bar to bend and some carefully placed heat will help. Or you could pick up a good used one on eBay for about $200.
Here is the twist. I found a few on ebay and other places, just trying to save the extra money. If all fails I will buy a good one without a problem, just wondering if it can be done.I've seen some success with laying the bike over on the opposite side and doing basically a simulated drop. Take all of the rear fairings off and set something sturdy underneath on the side of the bend. Gently lean it over onto the blocks you setup and apply some pressure to try to bend it back the other way.
Do this wrong though and you'll make a double bend which looks worse. You gotta have some sense about how metals bend in order to know where to place the blocks and how much pressure to apply. I've seen this used as a last resort just ahead of buying a new sub-frame. It's not perfect, not even close. It's tricky and far from anything scientific. You of course have to bring some friends to help lean the bike on its side and pick it back up.
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If I was going to try and straighten it, I would strip everything off it. All the body work, all the electrical, all the exhaust system, everything. Get it down to just the bare sub-frame. Then I'd figure out how I could attach a lever to it. I'd also figure out how I could secure the bike so I didn't push it off the stand or knock it over. Then I'd try and give it some small corrections to see how much force it will really take to move it. If it looked doable I'd proceed with applying the force needed to correct it.
Couple of points, you don't want to bend any of the attachment points at the frame. If that is where the bend is now, just throw it out and get a new one.
Aluminum really doesn't not like to be bent. You have to look at the grain and bend it so the bend is across the grain of the metal and not with it. If you bend it with the grain of the metal, it's going to crack for sure. You should inspect the whole sub-frame for cracks before you begin. Good chance it's already cracked from being bent and you should just throw it away.
Heat can help get aluminum to bend without cracking. You have to apply a good amount and it really takes practice to know how much to heat it. It's not propane torch heat, it's map gas or acetylene gas kind of heat. It's also really close to the melting point of the aluminum. So... this should be considered if you plan on trying heat. There are lot of other parts on the bike that you wouldn't want to expose to that kind of heat so you have to be very careful when your applying it. It's also going to take any coating or anodizing off the aluminum so consider that too before heating it.
It's junk already so trying to straighten it isn't a bad thing. The worst that can happen (assuming you don't set the bike on fire or something) would be you have to throw it out and get a replacement. You already have to do that so it won't hurt to try.
Best of luck with it if if you give it a go.
Couple of points, you don't want to bend any of the attachment points at the frame. If that is where the bend is now, just throw it out and get a new one.
Aluminum really doesn't not like to be bent. You have to look at the grain and bend it so the bend is across the grain of the metal and not with it. If you bend it with the grain of the metal, it's going to crack for sure. You should inspect the whole sub-frame for cracks before you begin. Good chance it's already cracked from being bent and you should just throw it away.
Heat can help get aluminum to bend without cracking. You have to apply a good amount and it really takes practice to know how much to heat it. It's not propane torch heat, it's map gas or acetylene gas kind of heat. It's also really close to the melting point of the aluminum. So... this should be considered if you plan on trying heat. There are lot of other parts on the bike that you wouldn't want to expose to that kind of heat so you have to be very careful when your applying it. It's also going to take any coating or anodizing off the aluminum so consider that too before heating it.
It's junk already so trying to straighten it isn't a bad thing. The worst that can happen (assuming you don't set the bike on fire or something) would be you have to throw it out and get a replacement. You already have to do that so it won't hurt to try.
Best of luck with it if if you give it a go.
Thanks for the advice! I was planning on just pulling the upper part off of the bike and mounting it to an old workbench. I was thinking of using a heat gun that heats up to 1050 F. I think its twisted a little bit further up from the mounting points to the lower subframe. Like you said, worst case possible, I end up buying a new upper, which I would have had to do in the first place:O Thanks again for everyone's help:bigthumb:If I was going to try and straighten it, I would strip everything off it. All the body work, all the electrical, all the exhaust system, everything. Get it down to just the bare sub-frame. Then I'd figure out how I could attach a lever to it. I'd also figure out how I could secure the bike so I didn't push it off the stand or knock it over. Then I'd try and give it some small corrections to see how much force it will really take to move it. If it looked doable I'd proceed with applying the force needed to correct it.
Couple of points, you don't want to bend any of the attachment points at the frame. If that is where the bend is now, just throw it out and get a new one.
Aluminum really doesn't not like to be bent. You have to look at the grain and bend it so the bend is across the grain of the metal and not with it. If you bend it with the grain of the metal, it's going to crack for sure. You should inspect the whole sub-frame for cracks before you begin. Good chance it's already cracked from being bent and you should just throw it away.
Heat can help get aluminum to bend without cracking. You have to apply a good amount and it really takes practice to know how much to heat it. It's not propane torch heat, it's map gas or acetylene gas kind of heat. It's also really close to the melting point of the aluminum. So... this should be considered if you plan on trying heat. There are lot of other parts on the bike that you wouldn't want to expose to that kind of heat so you have to be very careful when your applying it. It's also going to take any coating or anodizing off the aluminum so consider that too before heating it.
It's junk already so trying to straighten it isn't a bad thing. The worst that can happen (assuming you don't set the bike on fire or something) would be you have to throw it out and get a replacement. You already have to do that so it won't hurt to try.
Best of luck with it if if you give it a go.
A quick update. So it was actually extremely easy to do. Got it down to just the subframe and started with the lower portion. I bolted a small length of construction chain to the edge of the frame and had my dad crank down a few times on it with a piece of thick metal piping while I held the bike up. It twisted surprisingly easy. Used a bubble level to check everything. Then attached the upper subframe and did the same. Honestly it took all of a combined 30 seconds to straighten everything to pretty much 100%. After everything was done I checked around for cracks or any kind of damage and didn't find anything. Re checked the torque on the bolts connecting to the main frame and everything was good. Saved myself $200 :bigthumb:
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Wow, I'm surprised it was that easy. That's awesome! Thanks for updating us on the process and results!A quick update. So it was actually extremely easy to do. Got it down to just the subframe and started with the lower portion. I bolted a small length of construction chain to the edge of the frame and had my dad crank down a few times on it with a piece of thick metal piping while I held the bike up. It twisted surprisingly easy. Used a bubble level to check everything. Then attached the upper subframe and did the same. Honestly it took all of a combined 30 seconds to straighten everything to pretty much 100%. After everything was done I checked around for cracks or any kind of damage and didn't find anything. Re checked the torque on the bolts connecting to the main frame and everything was good. Saved myself $200 :bigthumb:
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