pipe dreams

[briyenkieth]

So here's a little sketch of my latest bad idea. Based off of a twin, would run the 99 gsxr forks I have with same yr wheel, late model gs500 rear wheel. Arched backbone running from the neck all the way down to where the lower legs of the rigid section would attach. Single down tube starting just above the motor mounts. Sprung seat with one of those fancy lil shocks. Mac two into one but unsure of what silencer.
I know the back looks a bit out of proportion but this is a sketch not a blueprint.
Biggest appeal to me would be the brakes. Disks front and rear would rule. Not to mention haven the trickest 400 around. Any thoughts?

[po-boy]

Looks good to me man. Now just make it happen...

[briyenkieth]

need a jig for this one, another bike would help as well but all that will be left of the original frame will be the neck and maybe the front and lower motor mounts. I'm going to draw the frame showing what I'm thinking structurally, see what the boys have to say. Might have to make some adjustments if it's really not safe. Plans so far call for a very beefy backbone. The same dia as the neck and a juicy wall. The way I see it working all the load will be carried thru this one piece. I'll get the drawing done so you can let me know what you think.

[jwhelan65]

Totally BAD ASS!.....Build it!

[Zooks]

Looks good. Can you flip the picture so it's easier for us to see? I got a sore neck looking at it. LOL

[russr33]

Looks sweet; definitely build it. Wish I could slketch like that.

JWHELAN check your PM!!

[atb1998]

one a friend is buliding.

[atb1998]

He is going to use a gsxr front end and 20" spoked wheels. The tank is going to be under the backbone. The engine is a yamaha 650 twin. pretty similar execution of a cool idea

[Billy Ricks]

The frame should be plenty stiff enough Try to keep the backbone as short as possible with the crank in the same plane as the axles.

[briyenkieth]

so ok this started as a thought, then a sketch and now I'm chasing parts! Got a line on a rear wheel. Gotta love craigslist, $45 with a tire in my city. It's missing the cush drive and brake rotor but it's a start.

Anybody know if the Cush drive from the 400 will fit a 500 wheel? Also are there particular rotors I should be scrounging?( certain year,model,etc.) Finally, for those who have more experience, would it be cheapper to a; have a neck made to accept the srad bearing? Or b; have a new stem made to fit the 400 bearing? Either way the neck comes off and I would use new bearings. Just trying to feel this out more.

[po-boy]

Wow, you don't mess around do ya? I'll let you do the homework, but I've got a cush drive/sprocket and rotor from my parts bike (81' GS750L) if you could make it work. Let me know...

[oshanac]

Dude, that looks awesome! Good luck!

[briyenkieth]

for zooks



The plan is to run the backbone down to the lower leggs of the rigid section. These leggs will be one piece bent into a "u" and welded into a notch in the end of the backbone. With the upper leggs i'm thinking the same one piece "u" but snaked thru a hole drilled thru the backbone. For the engine craddle my thought is this, that's all it will be just a craddle, I see all the loads being carried thru the backbone. Am I right or am I way off? That being said plans are to cut the down tubes just above the motor mounts in front and behind the lower front mounts. On the front I think it would be easiest to heat and bend a piece of solid stock to bridge the down tubes and the have a solid base for the single downtube. On the lower mounts I figured another "u" to tie the lower frame rails toghether and pick up the rear lower mounts. Then tie it together at the bottom with the two pieces. Solid frame or teriffic joke?

Edit: all tubing will be DOM of at least .120" wall with a solid round stock bridge for the downtubes. So I don't see any problems material wise.

[briyenkieth]

Picked up the rear wheel today and came up on the front tonight while browsing eBay. I'm now financialy invested so I guess I'm at least going to get the forks and wheels onto my bike for now. The wheels don't match but with the rotors and sprocket it should be hard to notice at first. So how did I do, I got both wheels for a $150 ? Seemed a fair rate,$40 for the rear and$110 for the front shipped. They of course need all the spensive goodies the bolt to them like rotors and cush drive and sprocket. Also need the rear brake caliper and master. Funny thing is I never actually finished version one of my bike. Just got sick of opening custom magazines and bobber threads and seeing the same dated recipe for a bike. Don't get me wrong I feel I did an ok job for my first bike but time to aim a bit higher.

[posplayr]

Very Nice Look

You seem to have created a very stylized design with beautify lines, but did it in a way that has sound engineering principles in mind (for a hard tail at least).

Obviously this is a cruiser and so the main issue is vertical weight and loads. Given the style you can make that backbone as large as required to get the strength. My only concern would be sizing it based on some similar bikes, and then how you plan to fabricate it. If it is too big it will be a challenge to bend such a smooth curve.

I see you integrated the bracing concept into the rear creating a truss system. With proper welds that will be way stronger than most swing arms as a swingarm comes together when it meets the frame at the pivot. Yours has a wide triangle which is the strongest structure (if I remember right).

Looking forward to how the frame turns out.

Good Luck