built my own swingarm

[posplayr]

My approach

My approach

Here is what I'm putting on my 86 GSXR 1100; period braced piece apparently was on the Schwantz 34 bike at one time. There is a picture attached, and the swing arms don't look the same, but it would have been on this vintage bike (1st Gen Slabbie 1100 swinger).

A modified Airtech tire hugger is my doing, and the chain guard is off a limited.

Pos

 

[Nessism]

my input is my own safety, full stop. another thread where people may label me as selfish, but i dont care. i would not trust that swing arm on my bike,end of story.
and how do you know who welded my bike and what with? you would be very surprised!!!!!

No one is asking you to put that swingarm on your bike. This thread is not about you.

 

[Nessism]

Here is what I'm putting on my 86 GSXR 1100; period braced piece apparently was on the Schwantz 34 bike at one time. There is a picture attached, and the swing arms don't look the same, but it would have been on this vintage bike (1st Gen Slabbie 1100 swinger).

A modified Airtech tire hugger is my doing, and the chain guard is off a limited.

Pos

I'm missing your point again. Yes, that is a nice swingarm. A road race swingarm. It's completely different from the OP's swingarm. Are you suggesting that he should brace his like your swingarm?

 

[Agemax]

No one is asking you to put that swingarm on your bike. This thread is not about you.

its not about you either but you seem quite happy to reply to it and put down everyone elses answers, except yours, because you are always right!

 

[posplayr]

I'm missing your point again. Yes, that is a nice swingarm. A road race swingarm. It's completely different from the OP's swingarm. Are you suggesting that he should brace his like your swingarm?

Ed I'm Fing suggesting that I'm putting it on my Fing bike; If you dont Fing chill I'm going to just plain Fing ignore U.

 

[Guest]

sheesh. it's been a long winter, eh guys?

 

[posplayr]

http://profilconsult.com/index.php?option=com_kunena&Itemid=113&id=251033&catid=5&func=fb_pdf


Re:swingarms.com​

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Posted by 531blackbanshee - 2008/12/16 21:26
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i built my own swingarm out of 4130 chro-moly(i also built my own tubing bender that i used to bend the
tubing).i have about 1500 miles on it and am very satisfied with it.it is extended 2" over stock and uses a
2000 r1 wheel and brake.i built and machined every piece of the swingarm including the pivot.it is
amazing what you can dream up when you have the skill and equipment to get the job done.i also
converted from 630 to 520 non o-ring chain while doing the conversion,and also fabricated my own
offset countershaft sprocket.quite a difference in handling with a rigid arm and a 200mm tire.here is the​

rightside,after a poker run in the rain where i fried the coils.thus the trailer shot.


http://i275.photobucket.com/albums/jj287/531blackbanshee/z1rbigtire005-1.jpg

Chrome moly swinger someone fabbed

 

[Nessism]

Now it's my turn to be scared...

 

[Nessism]

This one looks like it would be easy to fabricate... http://redlinecycle.com/swingarm - direct fit 2.html

 

[posplayr]

Road tested

Road tested

Ed,
Apparently this is the same arm, but with the bike is come complete shape. He is running a 180 on the rear with at least some 1500 miles.

Also that is a clean Kawi swinger.

If you start with a stock swinger and are mindful of welds/gussets, hopefully stiffness goes up from there.

Jim

 

[Guest]

I've got a spare wheel barrel frame if you all want to build a swingarm. :-\\\

 

[tkent02]

I've got a spare wheel barrel frame if you all want to build a swingarm. :-\\\

I built mine out of an old swingset.

 

[briyenkieth]

wow and I thought I was wound up tight. At least I got an excuse, I quit smoking. I agree with you guys that it needs some brace of some sort but do we need to talk so much $hit to each other and bash bikes that aren't being discussed here. Like hammered I'm also a certified welder and I "know" my $hit ain't going to break, so lay off all the blah blah blah.
It takes real balls to build something yourself. This dude posted his build, I'm sure, looking for constructive feedback. Not a bunch of bull$hit that took up eight pages.

Edit: upon second look it appears to me, not an engineer, to be flimsy looking. Particularly around the axel. Is the axel box from a stock swingarm? If so there's a weak link there, unless it was slugged together at that joint. I do understand that you used 1/4" wall but stock wall thickness is on the thin side. Just a thought but maybe you could start fresh with new leggs and have a machine shop cut you some new "boxes". Then put the bend in them to get the angles. Still have to agree about the brace even after. I mean why not! Custom braced swingarms are the cats pajamas and draw lots of ewws and ahhs. Plus all the added strength. At that point though $ might be the same as grafting a proper arm from another bike. Just thinking cause I can't sleep.

 

[Hammered]

Now it's my turn to be scared...

Why would this Swingarm scare you?. Do you know the properities of 4130 CM?, Even at the same wall thinckness it will out perform the thinner mild steel STANDARD tubing used in a stock swingarm.

 

[Nessism]

Why would this Swingarm scare you?. Do you know the properities of 4130 CM?, Even at the same wall thinckness it will out perform the thinner mild steel STANDARD tubing used in a stock swingarm.

The diameter of the tubing on that swingarm is small, which will create a flexi structure. 4130 may be stronger than mild steel, but the stiffness per unit of material is the same.

 

[posplayr]

The truss structure is going to make the swing arm much stiffer than you would think

 

[Dave8338]

Having no idea how to fab anything and not building anything more complicated that Chef's wheel barrel frame...IF the welds hold and a good brace is added at the pivot point, that swing arm is just fine.

As far as the "drag race only" application, have you ever seen the torsional flex that drag machine (bike, car, or truck) goes through when the clutch is dumped? Ever sat in the seat and had "seat of the pants" experience of that force? Ever had to refab a "factory designed/built vehicle" for race applications because it was either too light or poorly designed when the hammer is thrown?

1/4" wall thickness over the 18"-24" swing arm that Nasty put together is OVERKILL to say the least. Because there will be little if any flex in the material that you used, the welds are the critical link here. Braced correctly, welded correctly, it would be the only part to survive a pile-up at any speed, and come out straight.

Nasty...I feel for you. It can be rough throwing "your work" out on a fourm. Those who know will offer good design suggestions and help where they can. Those who don't will criticize and slam you, for lack of real world experience and next to no fab knowledge. No one here has calculated all the factors that are going to apply to that particular swingarm and unless there is a full table of the #'s before those that are throwing stones and they can read the numbers and do the math...it is all speculation.

Make sure the welds have penetrated all the way through (a bevel on the materials to be joined works very well and two to three passes may be needed depending on the welder-wire-rod -flux and heat being used) and a good gusset brace at the pivot and ride it.

Start slow and use a laquer based primer (it will crack not flex if there is stress movement) over the welds instead of paint and watch them closely and you'll be fine.

 

[Nessism]

The truss structure is going to make the swing arm much stiffer than you would think

I seem to remember Ducati making some truss design steel swingarms, but the tubing diameter is roughly double what the guy used.

 

[errorcauser]

I've got a spare wheel barrel frame if you all want to build a swingarm. :-\\\

LOL Is it heavy duty ?

Im not the sharpest tool in the shed, and i'll admit i just don't get all this. Why build your own swingarm ? Why not just get your hands on what was there to begin with and put it back ?

See ? I told you i don't get it.

 

[Hammered]

I seem to remember Ducati making some truss design steel swingarms, but the tubing diameter is roughly double what the guy used.

The purpose of using alloys like CM is to lighten the weight by be able to use a smaller dia and gauge material. Underbracing like the photo shows increases its ability to resist flexing to the point of failure by a larger amount. And the tubing used in stock swingarms is the stuff to be wary of. Youre looking at .080" NON Dom tubing. Its a medium grade of mild steel. In many cases, the backyard designer has roughly the same level of ability and access to higher grades of materials than the engineers that created the 1980 GS750. A quik Google will land you more useful information than was avilable 29 years ago.