Author Topic: 1975 CB550F Bobber Project DIFFERENT/UNIQUE - PIC HEAVY (Read 4255 times)

WWW.RU · « **on:** April 11, 2013, 05:12:59 PM »

Hello Everyone,

I just joined the forum, but i was lurking here for a while as a guest.

I wanted to share my project.

Here it is, the day i got it:

Stated the dis-assembly over some beers and got to this point:

I wanted to do something different than your typical hard-tail (pipe) set-up, so my buddy gave me an idea to use plate. After some sketching and cardboard mock-ups i made these plates for it (3/8" thick plate + 1/8" at the rear wheel). I work for a fab shop, they have a big CNC plasma table that burns plate out straight from AutoCAD.

Also, ordered an HD peanut tank, it has no tunnel, so it will mount real high, kind of like frisco style.

Here is a mock-up picture:

Started to weld plates to the frame. Basically, the concept was to reach that parallel between the ground and the frame using plate work, because i did not want to mess the the part of the frame that engine sits in, so here is what i came up with:

Basically, this is a 1/4" thick plate, that hugs the frame in the front (eventually foot pegs will be mounted to it) and then it meets the 3/8" thick plate to form the hard-tail.

As always, nothing ever fits right, so there was some grind-to-fit work to make things line up:

Than, 1/8" thick spacers were welded on (i am a bit rusty on my welding technique)

Then, hard tail extensions were welded to the frame (tacked) and here is the result:

Thenit was time to brace the hard-tail and cut the frame. I was holding off on the frame cutting as knew that it was basically a point of no return.

Also added a horizontal brace that will also serve as a battery tray (1/8" thick plate with logo incorporated)

Then i added some 1" dia vertical braces:

Tank and fender mock-up (light will be removed)

This is where it sits now, kind of pressed on time right now, but need to get it going soon. Obviously everything will be de-tabbed, removed, etc. I am going for that "minimalistic" look.

Let me know what you think.

Thank you.

goldarrow · « **Reply #1 on:** April 11, 2013, 05:21:02 PM »

cutting/detabbing not my cup of tea, but will be following....looks like a nice project....

65Ch3v3LL3 · « **Reply #2 on:** April 12, 2013, 03:38:15 AM »

Interesting way to do it. I think the flat side plates need some detail though, they seem kind of plain. Some speed holes would have been cool. Or maybe you could cut a thin sheet plate with some holes cut out and weld it on top of the thick plate so you get a 3D effect.

WWW.RU · « **Reply #3 on:** April 12, 2013, 04:25:49 AM »

Quote from: 65Ch3v3LL3 on April 12, 2013, 03:38:15 AM

Interesting way to do it. I think the flat side plates need some detail though, they seem kind of plain. Some speed holes would have been cool. Or maybe you could cut a thin sheet plate with some holes cut out and weld it on top of the thick plate so you get a 3D effect.

Not a bad idea. My goal for this year is to get it going, then paint it for next season. It will be a good time to add accent plates then.

Thanks.

Mister Gumby · « **Reply #4 on:** April 12, 2013, 06:52:35 PM »

That bottom plate is brilliant, I love the blend of design and structure.

WWW.RU · « **Reply #5 on:** April 13, 2013, 09:23:52 PM »

Quote from: Mister Gumby on April 12, 2013, 06:52:35 PM

That bottom plate is brilliant, I love the blend of design and structure.

Thank you!

I am structural engineer by trade and it just seemed natural. Also, I locked myself in on the tire size with such bracing scheme, cannot go any wider.

chris mcshifty · « **Reply #6 on:** April 13, 2013, 11:28:28 PM »

Very interesting and original I like it !!

brandEn · « **Reply #7 on:** April 14, 2013, 12:25:33 AM »

Welcome to the forum!
I like your project and will be tagging along. If your not a member at over on HondaChopper you should check them out, you will get lots of experienced hardtail guys over there.
http://hondachopper.yuku.com/

Viktor.J · « **Reply #8 on:** April 14, 2013, 12:53:14 AM »

Looking good ! interesting to see the final result !

WWW.RU · « **Reply #9 on:** April 17, 2013, 07:19:51 AM »

Worker on it last night for little. Started the de-tabbing process and weld grinding. Looking pretty good so far. I need to weld another brace in where the seat is going to, and 1/4" lever plate on the left side and it should be done for now.

Here is a quick pic:

Bankerdanny · « **Reply #10 on:** April 17, 2013, 07:58:25 AM »

Very creative. I am looking forward to seeing the rest of the design unfold.

iron_worker · « **Reply #11 on:** April 17, 2013, 08:15:19 AM »

Unique/different: yep!

Heavy as all hell: YEP!

The reason tubing is used for frames and structural components is because it's strength : weight ratio is very high as I'm sure you know as a structural engineer. Weight is pretty damn important to the performance of a motorcycle obviously. I guess the good part is you've added it down low.

Also, that battery is not a sealed battery and should not be on it's side like that. You're going to end up with acid everywhere!

I am curious to see where you take this project though.

IW

WWW.RU · « **Reply #12 on:** April 17, 2013, 09:57:01 AM »

Quote from: iron_worker on April 17, 2013, 08:15:19 AM

Heavy as all hell: YEP!

IW

Industry i work in we have a saying: "Heavy is goooood!"

I am a bit concerned with the weight of platework, but i was going for something different.

Thank you for the pointer on the battery, i will have to think about that one, maybe i will just keep it vertical for now and then later get a sealed battery, one that is lighter as well.

Bankerdanny · « **Reply #13 on:** April 17, 2013, 10:41:37 AM »

Look for the LiFe batteries. They are not that much more expensive than a sealed AGM, but are much smaller and MUCH lighter.

WWW.RU · « **Reply #14 on:** April 18, 2013, 10:55:22 AM »

Did a bit more work last night. Pretty much done with welding the frame, need to set a day a side to grind everything smooth, or close to it. Now i have figure out a seat, tank, controls, etc.....just small stuff

Here is some progeress pics. Springs for the seat will be mounted to a cross brace:

65Ch3v3LL3 · « **Reply #15 on:** April 19, 2013, 12:36:57 AM »

Looking good. Definitely unique.

Gman · « **Reply #16 on:** April 19, 2013, 12:37:26 AM »

Wwwru,

I'm not a fan of the chopper/bobber style - just my preference. I am, however, a huge fan of people who fabricate their own stuff, particularly if it is unique and is a reflection of your vision for the bike. Well done and I look forward to seeing it come together.

Cheers,
G

WWW.RU · « **Reply #17 on:** July 21, 2013, 03:57:48 AM »

Hello again,

I apologize for not posting for a while, just been busy.

Basically at this point i have the bike running. I test drove a couple of nights ago and........well it is bouncy, but its a hard tail

Please note that exhaust pipes are just temporary, I am probably just going to leave the headers on, and weld "2-into-1" system, which will be hidden behind 1/4" plate work that i have welded to the frame. Basically i am going to connect the outer 2 cylinders to the inner 2 and run then "inside" the bike frame.

Here are some pictures:

Making "Z" bars from 7/8" pipe

Then the seat (got springs from eBay and using an HD door hinge

Then I started the reassembly

Cleaned up the front-end a bit

Like i said, I was able to get it started and ride it.

There are a ton of things to do on it yet, i was just worried about re-wiring it. But i was able to figure it out using simplified wiring diagram.

I will post updated p[pictures soon.

WWW.RU · « **Reply #18 on:** December 03, 2013, 09:44:46 AM »

Just a few update pics.

Got the wiring and charging system figured out, but need to clean-up wires yet. Also, having some issues with it running/idling, but I am pretty sure that spark plug caps are at fault here. I had the jets drilled out to account for pod filters and future open exhaust.

It runs, but runs real rough and the front end is real bouncy. I did change the fork oil and rinsed the inside of the tubes with mineral spirits twice, but it did not solve the problem. I am pretty sure that the front tire might have a flat spot in from sitting still for quite a few years.

This is how it sits now, but there is still lots of work to-do:

Thank you.

News:

Author Topic: 1975 CB550F Bobber Project DIFFERENT/UNIQUE - PIC HEAVY (Read 4255 times)