MY 1978 XS chopper/ Custom

[natemoen]

If you look at the concept drawing you can see the shock on the front girder, its pretty obvious and not hidden.

[tcoop]

Looks like you just don't have the suspension part on there yet if this is what your finished product will look like.


You'll have to let us know how well the brakes work (and handling) with that design. Definitely have some creative thinking going on here.

[tcoop]

Roccet you pictures are not showing because of extra stuff in the url

?action=view&current=

"http://s142.photobucket.com/albums/r90/tarmacsports/?action=view&current=frontendconcept.jpg"

If you click on the IMG code to the right of you picture then paste here it should work.(with out the quotes)

"[IMG]"http://i142.photobucket.com/albums/r90/tarmacsports/frontendconcept.jpg"[/IMG]"

[WMarshy]

+1 to xs11lover ..."I'm thinkink I'd be happy right here"

Have you done any formal/informal engineering analysis on your design? I personally would be hesitant about that kind of mod without doing some FEA on it first. I mean, how are you going to size your shock, trial and error? Could be putting your life at risk and maybe others...

[fredintoon]

- - - Looks like you just don't have the suspension part on there yet if this is what your finished product will look like. - - -

Hi Ty, Nate,
If that sketch is drawn to scale the front wheel will have an inch or so of negative trail.
Which will have the effect of trying to whip the front end around through 180º.
It won't make 180º of course but it's trying to do the right thing because the design is a trailing link.
And what they do is dive the front bike when braking.
No matter how billet-machined and cutesy-looking they are.

[Schming]

Am I ...

...seein' that as soon as You'd tap that front brake the shock will contract, wheel and tire will rise into the fork brace or fender and lock the front wheel ?

[roccet]

Thank you guys.. and here are some answers

...seein' that as soon as You'd tap that front brake the shock will contract, wheel and tire will rise into the fork brace or fender and lock the front wheel ?

The shock distance is exact. its actual the rear shocks that came stock on the XS. Yes i have done a structure test and found my failure spots.
My trail is positive 1.475 inches.
Solidworks is what i use. I did a full tolerance check, Stress test,
Ill have to post my AVI of it .. i can show you the motion..
I also am making an adjustable cam style hub to see what i like better.
It will change my trail a bit and the position of my shock mount which is all good . I feel confident about my positions etc but i feel more confident when i have more choices than just being locked in..
Thank you guys for posting questions and comments.. I REALLY appreciate them. Im looking for a question that stumps me and makes me think a bit. Its all about making a better design that works...

The angle is a bit off as far as the picture goes so its hard to see the actual trail. It is all to scale btw.. What i wanted to achieve is a bike that looked raked out but infact was not. I tried VERY hard to keep my wheel in the stock position for the trail purpose.
I learned alot about bike engineering on this project. My next project next year will be to build Everything from scratch. I just starting chopping and modifying , Building till i got kind of what i wanted all along the way doing small little assembly drawings like the one you see.

[roccet]

I really liked it at this stage but I really wanted a bike that was just like WOW look at that badass bike.. So thats what im trying to achieve. But with a twist..
Im looking for someone to say what kind of bike.. and i will say a 1978 Yamaha XS1100.

I just dont want to go OVERboard. like oh look at that its a little to over the top who would ride that??

[roccet]

Interesting build, I like the color. It will be interesting how the front end handles. Have you applied any FEA to your fork design? Definitely don't want to find out the hard way that your almost at the yeild point of your material!

Ya i agree. I have ran this through solidworks for months before i built it.
I did it on both sets of forks i designed. this was by far the most impressive as far as my numbers go. I am all about safety. I am a designer by trade. I design helicopter products, Medical products, and a mix bag of other type of products. I used my knowledge and a bit of help from a senior engineer from an Aircraft company to help me with the design. Even with all of that i still have a fear so better to over build i say..

[DGXSER]

Being a former aircraft engineer, I recognized that to be the work of an aircraft designer. Carefully and strategically hollowed out frame for the maximum strength with minimum weight. Yep, it may not be rocket science but then rocket science is not all its cracked up to be either.

I guess the drawing/picture posted is deceiving, it would appear that your trail will be negative from that view. As in the line of the center of the steering axis seems meet teh horizontal plane of the bottom of the tire fall behind the vertical axis of the axle.

[roccet]

Now ... Head light choices..
The one in the picture is from a Subaru STI . its just sitting there..
Do you like it.? Why or why not..

The one in the solid model I am not sure i like it.. i was just playing with the idea of making one. But if i do make one i want it so custom that you will know right away that its not a stock light.. so Fire some choices at me..Tell me what you think. But keep in mind Modern, Tasteful and Clean looking. Thats the criteria

[roccet]

Being a former aircraft engineer, I recognized that to be the work of an aircraft designer. Carefully and strategically hollowed out frame for the maximum strength with minimum weight. Yep, it may not be rocket science but then rocket science is not all its cracked up to be either.

I guess the drawing/picture posted is deceiving, it would appear that your trail will be negative from that view. As in the line of the center of the steering axis seems meet teh horizontal plane of the bottom of the tire fall behind the vertical axis of the axle.

You will find this a bit interesting then. I designed a landing gear for an X plane two years ago. This was based from that design. My original design was to withstand a 10klb drop test at 30 feet at the tune of 2G
The only part that i changed was the location of the shock to the Control arm/Fork. I moved it a bit closer to the lighten hole. I did how ever take that into consideration all the Down force is not at the extended part of the arm but yet at the upper section of the arm allowing more force to be applied. Also these are 1.5 inches thick 6 inches wide and each cross section is 1.25-1.5 wide. yup she is pretty Dense and strong as hell.
sorry to go all "flighty" but im sure you can appreciate the design knowing that. .. Thank you for your comments I REALLY appreciate them..

...seein' that as soon as You'd tap that front brake the shock will contract, wheel and tire will rise into the fork brace or fender and lock the front wheel ? >>>>>

Yes i did see that and have made adjustments accordingly. You were good at spotting that. If you notice the arm that comes from the end of the fork to the hub then the hub attached to the shock.. that piece has been extended for my adjustment.
I have also changed the hub piece to be more of a cam.. with adjustment. It will affect my trail a bit but in my stock position that you dont see im almost 1.5 inchs so i can spare just a hair of room... Thank you had i not known that that You would have Saved my butt. .. Thats why i love Solid modeling..

[jwhughes3]

your design looks a little like this...

http://www.motorcycledaily.com/2011/01/a-peek-at-the-honda-mx-skunkworks-circa-1985/

The second bike shown in closeup looks a bit similar except the spring/shock is located in a different place.


John

[roccet]

front end.

whooaa.. looks like a bit more challenging to figure out pivot points and strength points.. actually looks much weaker than my MASSIVE setup but obviously they got it to work well. And being that its a dirt bike im sure it gets a ton of abuse.

Thanks for sharring that.. now i feel much better about my setup..

[fredintoon]

whooaa.. looks like a bit more challenging to figure out pivot points and strength points.. actually looks much weaker than my MASSIVE setup but obviously they got it to work well. And being that its a dirt bike im sure it gets a ton of abuse. - - -

Hi roccet,
yeah, complicated little thing, ain't it?
As to it's strength, even if offroad riding stresses are more than you see on the road, it's carrying mebbe 30% of what an XS11 weighs.
And, while your main girders look like they came off the Forth bridge, his suspension link is a U-shape while yours are single arms which puts all the flex resistance onto the wheel axle.
And your design is still a trailing link.
Trailing links suck.