How bendable are GS650G stock exhaust pipes?

[Anonymous]

I just got a 1981 GS650G, which I am in the process of getting running.

This site has been a great resource, and most of the questions I had were already answered in other posts. I didn't find anything on this, though.

The bike's original owner had a windjammer and a big trunk on it. It looks like he may have had saddlebags, too, as he welded 3 inch extensions onto the exhaust brackets and bent the mufflers down so instead of curving up they go straight back. It looks like he made the bend to bring the mufflers closer to the rear wheel to retain some cornering clearance, but the mufflers will still be the first thing to touch down. The bend occurs in the header pipes right before the muffler.

When I look at the bottom of the pipes where they are bent, there is a bulge on the bottom of the pipe where the bend occurred. It is in the same place on both pipes.

I'd like to have more cornering clearance, but I don't want to break the pipes by bending them back. Also, I want to keep the bike stock, so I don't want to switch to a different exhaust system.

Any Ideas on how best to do this? I'm thinking maybe heat it up and pull up on it as hard as I can.

Thanks.

[WifeofDink]

I would cut the bend off and get that small section replaced, if you heat the pipe up you run the risk of cracking it, under no circumstances pull on a heated pipe as it will definitely crack

[Anonymous]

Good advice.

In thinking about my options, I've decided to leave it alone and see how it corners. I don't know if the pipes are rusty inside, or how brittle the metal is. I'm reasonably sure that if I mess with it, it will be a can of worms.

It's just a really wierd thing to see done to a bike, so I didn't notice it when I bought it. I think the original owner was some kind of mad hobbyist.

On the plus side, if I want to bolt giant saddlebags on it and ride it around the world, there's room.

[Anonymous]

If you want to put the pipes back right, you better just go get a set of used ones, or new ones if you can afford it.

Now, how to best bend pipes. You will not break them if you heat them and bend them. That is the correct way to bend steel tubing. Your chome will peel off, and you will probably collapse them if you try to bend without a mandrel, too.

If you decide to bend up a custom set of headers in one piece, the trick is to completely fill the pipe with extremely fine DRY sand and weld the ends off, either with caps or just pinched shut. You can then heat and bend to your heart's content, as long as you don't stretch things so far that the thinning section breaks. You can then empty the sand out, have said pipes polished, and chromed. Be careful where you dump that sand, it's REALLY hot.

Steel, unless it is already rusted to pieces will not break when heated and bent. Aluminum goes "hot short" and gets brittle if heated and bent. It will just crumble if heated to a dull red and bent, that's what makes it so tricky to weld and cast correctly. Any residual stresses will break the weld or casting before it cools to its full strength (yeah, I play with that stuff, too).