250-500cc Subframe

Took a little digger on the motocross track, ended up with a grade 3 shoulder separation and a subframe that looks like this.
Any idea if it can be straightened? If not what other models match up with a 2012 WR300?

heat it up with a torch and bend it back..it may break tho. if it does work it probably wont be as strong in the future. ive straightened out levers that were pretty bad, but they were forged maguras.

Wow! I've never seen a subframe bent like that. Yes, just bend it back. The part that is bent isn't bearing any load.

Funny thing is it didn't break the rear fender, just ripped the bolts right out of the plastic. I'm assuming it's gonna take some heat to bend them back even close to where they were originally.

Have you a side image and measurements? I know the 360 2002 frame is similar to 125 2004 but 125 had extra gussets i had to fettle plastics to get it to fit nicely.
I can measure the fixing points an air box points etc on my 360 if that helps.
Failing that search halls for subframe an cross reference that number with other years.
Good luck with shoulder and straightening.

I fixed this when I found out a new one was $1248AUD.
Was out of square and twisted in more places than one. It took some effort to get it right and had to cut the cross brace out and reweld.

You'll get it done.

you must use heat or it will fatigue/crack

The procedure that hasn't failed me is to anneal an Al work piece first before trying to straighten it.
I soot the piece up with a dirty torch flame. Then heat the part with a clean flame till the soot just burns off. The annealing temperature is close to the melting temp, so care must be taken.

What's wrong with it?

Lol JK. It will fatigue either way, the fatigue and workhardening has already happened. But still, heat it or it will break for sure. If you get it hot enough it might not. Then, after cooling maybe could have a bead of weld put down the troughs to strengthen? Need a qualified aluminum welder to chime in.

Yeah for sure I was thinking of Big Timmy. I'll try and stir him up.

Guy that was riding with us that day said he thinks he can fix it, he owns an aerospace company so I'm hoping he can get it done and save me $500.

That's It. Xcuvator has it right. A sooty flame coat and go to a neutral flame and warm it until the soot burns off. You're not trying to burn it deliberately off with the flame, just warm it until it dissipates. It will burn off at about 600F or so. It melts at 1214F.

To get those forged ears hot enough to bend you will be somewhere in between these 2 temps. Probably upwards of 700F. If you're not comfortable with this go to a weld supply and ask for a few "Tempsticks" heat crayons, like a 650-750-850F. It'll melt when it get that hot so there's no guess work. Once heated, be ready to bend it when its hot, that's the best and only time. Have a partner ready, you only want to do this once. Use a vise with soft jaws to clamp to the forged frame ears, so you have some leverage. The forged ends are going to be the most difficult sections to straighten. If you use a hammer on it, it will likely break. Work slowly with your heat. You will feel it when its ready to bend. Don't force it, heat it until its malleable or it will break. Then use the vise to press it straight between the jaws. Shim it if necessary in the jaws to over bend a little so it stays straight. Keep the heat on it too because the vise will draw off the heat quickly when working it. If you get it straightened it will be annealed and the heat affected zone needed to re-bend or straighten it back will be somewhat soft but it will work/age harden over time.

Looks like boogies subframe was worse than yours. Looking at yours, I can't tell if its supposed to have that kick out on the right side or what. If so a few strategically placed relief cuts and some Tig work may be necessary to get it to refit its original position when static. You don't want to have to bend it to fit. Tack weld it in place mounted on the frame, if any relief cuts are needed once you get it to fit correctly.

These subframes are combinations of forgings and extrusions simply Tig welded together. Areas of original welds are somewhat isolated and heat input is minimal. Its not likely any heat treating was ever done to these. Jump/skip any welds around, if you need to do any welding on it to keep heat to a minimum.

Then run it and save your money.

Thanks Big Timmy. I wondered about forging annealing temps. I thought melting point was lower.

Thanks for the lesson, I know I would have snapped it for sure trying it myself. I will pass this info on to the guy doing the work for me, hopefully he already knew this.

You can never tell the quality of the grain structure of a sectional component like that. If it was a poorly done casting welded there to the end of the top pieces of tubing, it would have probably broke for sure being bent that far in the first place.

Again heat it until you can feel it become malleable. Don't force it as it has already taken a severe amount of punishment. The current grain structure of the offending area of these ears, after this damage was done has been severly rearanged on a granular level. Its not likely going to want to do this again, back to its original shape with out wanting to break this time. Heating it to the point of it cooperating is the key. Don't overheat to the point of it changing color (yellowish brown) or you will be in trouble.

Hope it all works out.

A small rose bud torch tip would also help disperse the heat evenly IMO.

Of Course, I would recommend a rose bud tip for sure. Thought that would be a given. Welding tips or cutting tips are for welding and cutting and nothing else! Rosebud tips are pretty much only used for heating.