K, first off pipe's for plumbing. You need some TUBING bent. I'll guess 1" x .083/.095.

If you have a race car shop in your vicinity they should have a 180* 1" die for making driveshaft loops.

Otherwise if you have a torch you can sand bend it. If you're stupid, sand bending's roughly eguivilent to hanging onto a pipe bomb. I've made some neat sand bent shit, but not telling you how.

I have a 180* 1" die, but shipping to Canada's a pita.

 

cut threads and screw on the big cast plumbing 90's.

dood, you serious? - schedule 40 is stoopid heavy for that application. don't do it. find somebody local who has some thin wall, 18-20g in that neighborhood. lighten up.
good luck and cheers, bcr

 

Well, I wasn't expecting the Spanish Inquisition! Seriously though, the top frame rails on this thing are 1.124" OD with a .105" wall thickness, 3/4" pipe has .113" wall so I didn't think .008" difference was enough to worry about. I'm starting to think maybe I should go without, it's going to look big & heavy under that little seat. Are there any advantages (other than cosmetic) to having a loop?

 

Thought I was just being helpful, pipe in the wrong application'll get you hurt homey.

Anytime you add a crossmember(tie the tubes together) it adds structural rigidity. But going to say that that's not the flex point in your frame anyway so then no, no advantage of a loop other than holding up the rear of the seat.

Opinions will vary...

 

the last few hoops I've made I did with 1/2" square tubing. strong, light, easy to fabricate. It'll disappear under your pan/bumpstop and give you a little more structure. cheers, bcr

 

OK, I was going to mount 2 alum. angle irons under the seat pan to mount it to the frame, maybe I could just extend back from that with a piece of alum. plate to support the seat bubble & mount tail light/ licence plate from , not bother having visible loop under the whole seat pan; avoid experimenting with pipe bombs!

 

I sand bent this;

It happens to be 1/2" black pipe because that's what the threads were in the light fixture.

Like I said sand bending can be dangerous, dont be stupid.

 

Ok, so did you cut your frame on the KH500? cuz I own a KH500 and I can tell you there has to be several feet of frame structure back there that adding a loop to would just look silly.

How about a pic of what you are working with and we can give you some good ideas.

 

ratty -

what, make sure the sand is super dry? vent the ends?

 

A small loop at the back will not carry much load, so it doesn't much matter what it's made of. I'd be prepared to try 3/4 conduit but beware of galvanizing when you weld it. nasty gases I'm told.

What I did on a couple of small Hondas was to grab an old SL frame with a rear loop and hack that off and transplant it onto my frame. That way it was strong enough, nicely bent and best of all, it was kicked up at the rear like an RC181. I got teh whole bike for like $25 so it was just part of the "harvesting" of useful parts.

 

quote:Originally posted by borzwazie

ratty -

what, make sure the sand is super dry? vent the ends?

Borz,

I've heard of guys putting the sand in an oven. Why not leave one cap off w/the pipe sticking straight up and preheat it all to remove the moisture?

All the caps need to do is retain most of the sand. There's no reason for them to be airtight and it's dangerous.

Started on that piece with my 1" die clamped in a vise and was going to bend around it. That didn't work for shit. Notice how the first bend starts abruptly and then gets loopy?

Found that by just varying the heat and pressure I could control the radius. Think on one of the Nisky garage builds they made a wooden buck to bend around, but I never have.

All that being said unless you want a piece with a variable radius and are handy with a torch just have a race car shop bend pieces for you.

 

you don't really need to sandbend anything with a wall thickness like pipe, you can work it with heat without crushing it as long as you don't heat the inside of the bend and keep the red area wide along the bend

 

<center></center>Remedial Tubebending 101

There's a story here, but I've had a long day. Look at the pics see if you can follow along. Maybe I'll fill in the blanks if anyone cares.